======================WEB_TERMS================================

ABI/Inform            A database of articles in more than 800 business-related 
                      periodicals and specialty publications since 1986. 
Abuse of Privilege    user performs an action that they should not 
                      have, according to organizational policy or law.
Access Control Lists  Rules for packet filters (typically routers) that 
                      define which packets to pass and which to block.
Access Router         A router that connects your network to external Internet.
                      Typically, this is your first line of defense against 
                      attackers from outside Internet.By enabling access control
                      lists on this router,able to provide protection for 
                      all of the hosts``behind'' that router, 
                      effectively making that network a DMZ instead
                      of an unprotected external LAN.
Access Provider       The company that provides you with Internet access and, 
                      in some cases, an online account on their computer 
                      system. 
Acoustic Coupler      A type of modem which converts digital signals into sound 
                      for transmission through telephone lines, and performs 
                      reverse operation when receiving such signals. 
                      Acoustic couplers generally have cups for telephone 
                      handset. 
Active Window         The top or front window in a multiple window environment. 
A/D Converter         A device used to convert analog data to digital data. 
                      Analog data is continuously variable, while digital data 
                      contains discrete steps. 
                      Additive Primaries 
                      Red, green, and blue are primary colors of light from 
                      which all other colors can be made. 
Address Resolution    Conversion of an IP Address to corresponding low-level 
                      physical address. 
AIX                   Advanced Interactive Executive - IBM's version of Unix. 
Aliasing              Visibly jagged steps along angled or object edges, due to 
                      sharp tonal contrasts between pixels. 
Analog                Continuously variable signals or data. 
                      Anonymous Login Convention (FTP) 
                      Standard username (anonymous) and password (guest) which 
                      allows login within FTP for purpose of retrieving an 
                      unprotected file. 
ANSI                  American National Standards Institute. This organization 
                      is responsible for approving U.S. standards in many 
                      areas, including computers and communications. 
                      Standards approved by this organization are often called 
                      ANSI standards (e.g., ANSI C is version of C language 
                      approved by ANSI). 
Application           Software that lets users do relatively complex tasks, as 
                      well as create and modify documents. Common application 
                      types include word processors, spreadsheets, 
                      database managers, and presentation graphics programs. 
Application backdoors Some programs have special
                      features that allow for remote access. Others contain
                      bugs that provide a backdoor, or hidden access, that  
                      provides some level of control of the program. 
Application-Layer     Firewall
                      A firewall system in which service is provided by 
                      processes maintain complete TCP connection state and 
                      sequencing. Application layer firewalls 
                      often re-address traffic so that outgoing traffic
                      appears to have originated from the firewall, rather 
                      than the internal host.
ARA                   AppleTalk Remote Access. A protocol (and product) that 
                      provides system-level support for dial-in (modem) 
                      connections to an AppleTalk network. With ARA, you 
                      can call your desktop Mac from a PowerBook and remotely 
                      access all available services - files, printers, servers, 
                      e-mail, etc. 
Archie                An information system offering an electronic directory 
                      service for locating information in Internet that is 
                      automatically updated. The best known use of archie is 
                      for 
                      scanning a database of contents of more than 1000 
                      Anonymous FTP sites around world with more than 2,100,000 
                      file names. 
ARP                   Address Resolution Protocol. Used to dynamically discover 
                      low-level physical network hardware address that 
                      corresponds to high level IP Address for a given 
                      host, for instance. ARP is limited to physical network 
                      systems that support broadcast packets that can be heard 
                      by all hosts on network. See also Proxy ARP. 
ARPANET               Advanced Research Projects Agency NETwork. A pioneering 
                      long-haul network funded by ARPA, an agency of U.S. 
                      Department of Defense responsible for 
                      development of new technology for military. It served as 
                      basis for early networking research as well as a central 
                      backbone during development of 
                      Internet. The ARPANET consisted of individual packet 
                      switching computers interconnected by leased lines. 
ASCII                 American (National) Standard Code for Information 
                      Interchange. A standard character-to-number encoding 
                      widely used in computer industry. 
                      Associate 
                      Linking a document with program that created it so that 
                      both can be opened with a single command. 
AV                    Audio-Visual. AV Macintosh models have video-capture 
                      hardware and have sophisticated sound (and video) 
                      recording capabilities. 
AU sounds             A type of audio format used in World Wide Web. 
                      B or Return to Quick Index 
                      B 
Authentication        determining the identity of a user that is attempting to
                      access a system.
Authentication Token  A portable device used for authenticating a user. 
                      Authentication tokens operate by challenge/response, 
                      time-based code sequences, or other
                      techniques. This may include paper-based lists of 
                      one-time passwords.
Authorization         determining what types of activities  are permitted.
                      once authenticated a user, they may be authorized 
                      different types ofaccess or activity.
Backbone              Network used to interconnect several networks together. 
Backup file           In Windows 95, a compressed version of original file and 
                      its locations created by Backup. 
Bandwidth             The capacity of transmission medium stated in bits per 
                      second or as a frequency. The bandwidth of optical fiber 
                      is in gigabit or billion bits per second range, while 
                      ethernet coaxial cable is in megabit or million bits per 
                      second range. 
Baseband System       A baseband system transmits signals without converting 
                      them to another frequency and is characterized by its 
                      support of one frequency of signals. Ethernet-based 
                      networks inside campus buildings are transmitted via 
                      baseband coaxial cable, with ethernet being only service 
                      supported by coaxial cable. 

Bastion Host          A system that has been hardened to resist attack, and 
                      which is installed on a network in such a way that it is 
                      expected to potentially come under attack. 
                      Bastion hosts are often components of firewalls, or
                      may be ``outside'' web servers or public access 
                      systems. Generally, a
                      bastion host is running some form of general purpose 
                      operating system
                      (e.g., Unix, VMS, NT, etc.) rather than a ROM-based 
                      or firmware operating system.
BAT                   Filename extension for a batch file. 
                      Batch Scanning 
                      Sequential scanning of multiple originals using 
                      previously defined, unique settings for each. 
Baud                  A unit of measurement that denotes number of bits that 
                      can be transmitted per second. For example, if a modem is 
                      rated at 9600 baud it is capable of transmitting 
                      data at a rate of 9600 bits per second. The term was 
                      derived from name of J.M.E. Baudot, a French pioneer in 
                      field of printing telegraphy. 
Batch Scanning        Sequential scanning of multiple originals using 
                      previously defined, unique settings for each. 
BBS                   Bulletin Board Service. A non commercial dial-up service 
                      usually run by a user group or software company. By 
                      dialing up a BBS with your modem, you can exchange 
                      messages with other users, and upload or download 
                      software. 
BGI                   Binary Gateway Interface. Provides a method of running a 
                      program from a Web server. Similar to a Common Gateway 
                      Interface (CGI). The BGI uses a binary DLL 
                      which is loaded into memory when server starts. While 
                      more efficient han a CGI, BGI must be compiled and is not 
                      easily portable to other environments. 
Bilevel               A type of image containing only black and white pixels. 
Binary                A numbering system with only two values: 0 (zero) and 1 
                      (one). 
Binary File           A file that contains more than plain text (i.e., photos, 
                      sounds, spreadsheet, etc.) In contrast to an ASCII file 
                      which only contains plain text. 
                      Binary Number System 
                      A counting system used in computers consisting of only 
                      1's and 0's (zeros). 
BinHex                A file conversion format that converts binary files to 
                      ASCII test files. 
BIOS                  Basic Input-Output System. Part of computer's operating 
                      system that is built into machine, rather than read from 
                      a disk drive at startup. 
bit                   A unit of measurement that represents one figure or 
                      character of data. A bit is smallest unit of storage in a 
                      computer. Since computers actually read 0s and 1s, each 
                      is measured as a bit. The letter A consists of 8 bits 
                      which amounts to one byte. Bits are often used to measure 
                      capability of a microprocessor to process data, such as 
                      16-bit or 32-bit. 
Bit Depth             The number of bits used to represent each pixel in an 
                      image, determining its color or tonal range. 
Bit-map               Generally used to describe an illustration or font file 
                      as being created by a predefined number of pixels. Also 
                      see Object-oriented. 
BITNET                An academic computer network that provides interactive 
                      electronic mail and file transfer services, using a 
                      store-and-forward protocol, based on IBM Network Job 
                      Entry protocols. BITNET-II encapsulates BITNET protocol 
                      within IP packets and depends on Internet to route them. 
                      There are three main constituents of 
                      network: BITNET in United States and Mexico, NETNORTH in 
                      Canada, and EARN in Europe. There are also AsiaNet, in 
                      Japan, and connections in South 
                      America. See CREN. 
Black Point           A movable reference point that defines darkest area in 
                      an image, causing all other areas to be adjusted 
                      accordingly. 
Booting               Starting up a computer via power switch, which loads 
                      system software into memory. Restarting computer via a 
                      keystroke combination is called rebooting or a 
                      warm boot. 
Bridge                A dedicated computer used to connect two different 
                      networks. It uses data link layer address (i.e., ethernet 
                      physical addresses) to determine if packets should be 
                      passed between networks. 
                      Broadband System 
                      A broadband system is capable of transmitting many 
                      different signals at same time without interfering with 
                      one another. For local area networks, a broadband 
                      system is one that handles multiple channels of local 
                      area network signals distributed over Cable Television 
                      (CATV) hardware. 
Broadcast             A packet whose special address results in its being heard 
                      by all hosts on a computer network. 
Broadband System      A broadband system is capable of transmitting many 
                      different signals at same time without interfering with 
                      one another. For local area networks, a broadband 
                      system is one that handles multiple channels of local 
                      area network signals distributed over Cable Television 
                      (CATV) hardware. 
Browser               A program that enables you to access information on 
                      Internet through World Wide Web. 
bps                   Bits Per Second is unit used for measuring line speed, 
                      number of information units transmitted per second. 
BSD                   Berkeley Software Distribution. Implementation of UNIX 
                      operating system and its utilities developed and 
                      distributed by University of California at Berkeley. BSD 
                      is usually preceded by version number of distribution, 
                      e.g., 4.3 BSD is version 4.3 of Berkeley UNIX 
                      distribution. Many Internet hosts run BSD software, and 
                      it is ancestor of many commercial UNIX implementations. 
Bug                   A mistake, or unexpected occurrence, in a piece of 
                      software or in a piece of hardware. 
Byte                  The amount of memory needed to store one character such 
                      as a letter or a number. Equal to 8 bits of digital 
                      information. The standard measurement unit of a file 
                      size. 
Cache                 An area of RAM reserved for data recently read from disk, 
                      which allows processor to quickly retrieve it if it's 
                      needed again. 
Caching               A process in which frequently accessed data is kept on 
                      hand, rather than constantly being from place where it is 
                      stored. 
Case-dependent        Software differentiation between upper and lower case 
                      characters. Also referred to as case sensitive. 
CCD                   Charge-coupled device. An integrated, micro-electrical 
                      light sensing device built into some image capturing 
                      devices. 
CD-ROM                Compact Disk, Read-Only Memory. A type of storage device 
                      that looks just like an audio CD and stores as much data 
                      as a large hard disk (600MB), making it a popular 
                      means of distributing fonts, photos, electronic 
                      encyclopedias, games, and multimedia offerings. As name 
                      indicates, however, you can't save or change files on a 
                      CD-ROM, only read them. Pronounced see-dee rom. 
CGI                   Common Gateway Interface. A method of running an 
                      executable script or program from a Web server. When a 
                      client requests a URL pointing to a CGI, program is 
                      run and results are returned to client. This enables 
                      dynamic web pages and ability to do database queries and 
                      other complex operations across web 

Challenge/Response    An authentication technique whereby a server sends an 
                      unpredictable challenge to the user, 
                      who computes a response using some form of authentication 
                      token.
Chroot                A technique under Unix whereby a process is 
                      permanently restricted to
                      an isolated subset of the filesystem.
CIE                   The "Commission Internationale de l'Eclairage". An 
                      organization that has established a number of widely-used 
                      color definitions. 
Circuit-switched      A type of network connection which establishes a 
                      continuous electrical connection between calling and 
                      called users for their exclusive use until connection is 
                      released. Ericsson PBX is a circuit-switched network. 
Clickable Image       Any image that has instructions embedded in it so that 
                      clicking on it initiates some kind of action or result. 
                      On a web page, a clickable image is any image that has a 
                      URL 
                      embedded in it. 
Client/server         relationship 
                      A client application is one that resides on a user's 
                      computer, but sends requests to a remote system to 
                      execute a designated procedure using arguments supplied 
                      by 
                      user. The computer that initiates request is client and 
                      computer responding to request is server. Many network 
                      services follow a client and server 
                      protocol. 
Clipboard             An area used to temporarily store cut or copied 
                      information. The Clipboard can store text, graphics, 
                      objects, and other data. The Clipboard contents are 
                      erased when 
                      new information is placed on Clipboard or when computer 
                      is shut down. 
Clipping              The conversion of all tones lighter than a specified grey 
                      level to white, or darker than a specified grey level to 
                      black, causing loss of detail. This also applies to 
                      individual 
                      channels in a color image. 
CMS                   Color management system. This ensures color uniformity 
                      across input and output devices so that final printed 
                      results match originals. The characteristics or profiles 
                      of 
                      devices are normally established by reference to standard 
                      color targets. 
CMYK                  Cyan, magenta, yellow, and black are base colors used in 
                      printing processes. CMY are primary colorants of 
                      subtractive color model. 
Colorimeter          A light-sensitive device for measuring colors by 
                      filtering their red, green, and blue components, as in 
                      human eye. See also spectrophoto-meter. 
Color Cast            An overall color imbalance in an image, as if viewed 
                      through a colored filter. 
COM1, COM2, etc.      Most serial ports and internal modems on DOS/WIN PCs can 
                      be configured to either COM1 or COM2 in order to 
                      accommodate situation where both may exist. The 
                      DOS MODE command is used to change output direction to 
                      such serial devices as modems. 
Compression           The reduction in size of an image file. See also lossy 
                      and non-lossy. 
Computer Search       Service 
                      Computer Search Service (CSS), a fee-based service, 
                      offers access to more than 500 databases, primarily in 
                      sciences and social sciences, from which Library 
                      can create customized bibliographies. 
Configuration         1. The components that make up a computer system (which 
                      model and what peripherals). 2. The physical arrangement 
                      of those components (what's placed and where). 
                      3. The software settings that enable two computer 
                      components to talk to each other (as in configuring 
                      communications software to work with a modem). 
Contone (CT)          An abbreviation for continuous tone. A color or greyscale 
                      image format capable of illustrating continuously varying 
                      tonal ranges, as opposed to line art. 
                      Cookies 
                      A file sent to a web browser by a web server that is used 
                      to record once's activities. 
Cookies               A file sent to a web browser by a web server that is used 
                      to record once's activities. 
Coprocessor           A chip designed specifically to handle a particular task, 
                      such as math calculations or displaying graphics 
                      on-screen. A coprocessor is faster at its specialized 
                      function 
                      than main processor is, and it relieves processor of 
                      some work. A coprocessor can reside on motherboard or be 
                      part of an expansion card, as with an 
                      accelerator. 
Coaxial Cable         A type of cable that contains two conductors. The center 
                      conductor is surrounded by a layer of insulation, which 
                      is then wrapped by a braided-metal conductor and an 
                      outer layer of insulation. 
CPU                   Central Processing Unit; brains of computer. The CPU 
                      interprets and executes actual computing tasks. 
Crash                 A problem (often caused by a bug) that causes a program, 
                      or entire operating system, to unexpectedly stop working. 
CREN                  Corporation for Research and Educational Networking. This 
                      organization was formed in October 1989, when BITNET and 
                      CSNET (Computer + Science NETwork) 
                      were combined under one administrative authority. CSNET 
                      is no longer operational, but CREN still runs BITNET. See 
                      BITNET. 
Cross-platform        Refers to software (or anything else) that will work on 
                      more that one platform (type of computer). 
Cryptographic         Checksum
                      A one-way function applied to a file to produce a 
                      unique ``fingerprint'' of the file for later reference. 
                      Checksum systems are a primary means 
                      of detecting filesystem tampering on Unix.
CSUNET                California State University Network. A packet-switched 
                      network that connects 22 campuses of CSU system. 
Cursor                The representation of mouse on screen. It may take many 
                      different shapes. Example: I-beam, arrow pointer, and 
                      hand. 
Cyberspace            A term used to refer to electronic universe of 
                      information available through Internet. 
                      D or Return to Quick Index
Data Driven Attack    A form of attack in which the attack is encoded in 
                      innocuous-seeming data which is executed 
                      by a user or other software to implement an attack.
                      In the case of firewalls, a data driven attack
                      is a concern since it may get through the firewall 
                      in data form and launch an attack against a system 
                      behind the firewall.
DAT                   Digital Audio Tape. The most common type of tape backup. 
Daughterboard         A board that attaches to (rides piggyback on) another 
                      board, such as motherboard or an expansion card. For 
                      example, you can often add a daughtercard containing 
                      additional memory to an accelerator card. 
Database              A file created by a database manager that contains a 
                      collection of information organized into records, each of 
                      which contains labeled categories (called fields). 
DCS                   Desktop color separation. An image format consisting of 
                      four separate CMYK PostScript files at full resolution, 
                      together with a fifth EPS master for placement in 
                      documents. 
DDN                   Defense Data Network. A global communications network 
                      serving US Department of Defense composed of MILNET, 
                      other portions of Internet, and classified 
                      networks which are not part of Internet. The DDN is used 
                      to connect military installations and is managed by 
                      Defense Information Systems Agency (DISA). 
DEC                   Digital Equipment Corporation. 
Decompression         The expansion of compressed image files. See also lossy 
                      and non-lossy. 
Dedicated line        A telephone or data line that is always available. For 
                      example, a leased telephone line can be dedicated for 
                      computer data communications. This line is not used by 
                      other 
                      computers or individuals, is available 24 hours a day, 
                      and is never disconnected. 
Default Route         A routing table entry which is used to direct packets 
                      addressed to networks not explicitly listed in routing 
                      table. 
Defense in Depth      The security approach whereby each system on the 
                      network is secured tothe greatest possible degree. 
                      May be used in conjunction with firewalls.
denial of service     someone  make your network or firewall
                      crashing it, jamming it, or flooding it. 
                      TCP/IP's UDP echo service is trivially
                      abused to get two servers to flood a
                      network segment with echo packets. 
                      You should consider commenting out unused
                      entries in /etc/inetd.conf of Unix hosts,
                      adding no ip small-servers to
                      Cisco routers, or the equivalent for your components. 
Denial of service -   nearly impossible  
                      to counter.  hacker sends a 
                      request to  server to connect to it. When the  
                      server responds with an acknowledgement and tries to 
                      establish a session, it cannot find the system that 
                      made the request. By inundating a server with these  
                      unanswerable session requests, a hacker causes the  
                      server to slow to a crawl or eventually crash
Densitometer          A measuring instrument that registers density of 
                      transparent or reflective materials. Colors are read as 
                      tonal information. See also colorimeter and 
                      spectrophotometer. 
Density               Density is a brightness control to lighten or darken a 
                      printout to more closely reflect its screen appearance 
                      and to compensate for deficiencies in toner or paper 
                      quality. 
Descreening           Removal of halftone dot patterns during or after scanning 
                      printed matter by defocusing image. This avoids moire 
                      patterning and color shifts during subsequent 
                      halftone reprinting. 
Dialog box            A window that displays additional options or questions 
                      when a command is chosen. 
Dial-up line          A communication connection from your computer to a host 
                      computer over standard phone lines. Unlike a dedicated 
                      line, you must dial host computer in order to 
                      establish a connection. Dial-up line is currently most 
                      popular form of Net connection for home user. 
Dichroic Mirror       A special type of interference filter, which reflects a 
                      specific part of spectrum, whilst transmitting rest. Used 
                      in scanners to split a beam of light into RGB 
                      components. 
Digital               Data or voltages consisting of discrete steps or levels, 
                      as opposed to continuously variable analog data. 
                      Digitizers 
                      A machine which converts analog data into digital data on 
                      a computer (such as a scanner digitizing pictures or 
                      text). 
Digitizers            A machine which converts analog data into digital data on 
                      a computer (such as a scanner digitizing pictures or 
                      text). 
DIP switches          Dual Interface Poll switches allow for either an ON or 
                      OFF setting with any number of circuits. DIP switches 
                      commonly allow you to change configuration of a 
                      circuit board to suit your particular computer. 
Direct connection     A permanent communication connection between your 
                      computer system (either a single CPU or a LAN) and 
                      Internet. This is also called a leased line connection 
                      because you are leasing telephone connection from phone 
                      company. A direct connection is in contrast to a SLIP/PPP 
                      or dial-up connection. 
Direct-To-Plate       Direct exposure of image data onto printing plates, 
                      without intermediate use of film. 
Direct-To-Press       Elimination of intermediate film and printing plates by 
                      direct transfer of image data to printing cylinders in 
                      press. 
Directory             A system that your computer uses to organize files on 
                      basis of specific information. 
                      Disk Defragmenter 
                      Arranges blocks of information for a file into adjacent 
                      blocks on your hard drive, which may significantly 
                      improve file access times. 
Disk Defragmenter     Arranges blocks of information for a file into adjacent 
                      blocks on your hard drive, which may significantly 
                      improve file access times. 
Dmax                  The point of maximum density in an image or an original. 
Dmin                  The point of minimum density in an image or an original. 

DNS                   Domain Name System. A general purpose distributed, 
                      replicated, data query service. Its principal use is 
                      lookup of host IP addresses based on host names. The host 
                      names are also known as domain names. Some important 
                      domains are: .COM (commercial), .EDU (educational), .NET 
                      (network operations), .GOV (U.S. government), 
                      and .MIL (U.S. military). Most countries also have a 
                      domain. For example, .US (United States), .UK (United 
                      Kingdom), .AU (Australia). 
Dmax                  The point of maximum density in an image or an original. 
                      Dmin 
                      The point of minimum density in an image or an original. 
DNS                   Domain Name System. A general purpose distributed, 
                      replicated, data query service. Its principal use is 
                      lookup of host IP addresses based on host names. The host 
                      names are also known as domain names. Some important 
                      domains are: .COM (commercial), .EDU (educational), .NET 
                      (network operations), .GOV (U.S. government), 
                      and .MIL (U.S. military). Most countries also have a 
                      domain. For example, .US (United States), .UK (United 
                      Kingdom), .AU (Australia). 
DNS spoofing          Assuming the DNS name of another system by either 
                      corrupting the name
                      service cache of a victim system, or by compromising 
                      a domain name server for a valid domain.
Domain names          Because it is hard to remember the  
                      string of numbers that make up an IP address, and 
                      because IP addresses sometimes need to change, all 
                      servers on the Internet also have human-readable
                      names, called domain names. For example, it is easier
                      for most of us to remember www.howstuffworks.com than 
                      it is to remember 216.27.61.137. A company might
                      block all access to certain domain names, or allow   
                      access only to specific domain names.

Domain Name Servers,  DNS, are an incredibly important but 
                      completely hidden part of the Internet, 
                      http://www.howstuffworks.com 
                      Contains domain name howstuffworks.com. 
                      So does this email address: 
                      brain@howstuffworks.com 
                      Domain name servers translate domain names 
                      to IP addresses.
                      There are billions of IP addresses currently in use, 
                      and most machines have a human readable name as well. 
                      There are many billions of requests made from domain 
                      name servers every day.

Domain Names Work     If we had to remember the IP addresses of all of the web 
                      sites we visit every day, we would all go nuts. Human 
                      beings just are not that good at remembering
                      strings of numbers. We are good at remembering words, 
                      however, and that is where domain names come in. You 
                      probably have hundreds of domain names
                      stored in your head. For example: 
                      www.howstuffworks.com -- a typical name 
                      www.yahoo.com -- the world's best-known name 
                      www.mit.edu -- a popular EDU name 
                      encarta.msn.com --web server that does not start with www 
                      www.bbc.co.uk -- a name using 4 parts rather than 3 
                      ftp.microsoft.com -- an ftp server rather than a web 
                      server 
                      The .COM, .EDU and .UK portions of these example domain 
                      names are called the top-level domain or first-level 
                      domain. There are several hundred
                      top-level domain names, including COM, EDU, GOV, MIL, NET,
                      ORG and INT, as well as unique two-letter combinations for
                      every country. 
Distributing Domain   Names
                      Because all of the names in a given domain need to be 
                      unique, there needs to be a single entity that controls 
                      the list and makes sure no duplicates arise. For example, 
                      the COM domain cannot contain any duplicate names, 
                      a company called Network Solutions in charge of this 
                      list.When you register a domain name, goes through one of
                      several dozen registrars who work with Network Solutions 
                      to add names to list. Network Solutions, in turn, 
                      keeps a central database known as  whois database that
                      contains information about  owner and name servers for 
                      each domain. If you go to the whois form you can find 
                      information about any domain currently in existence. 
                      Microsoft wants to maintain its own domain name
                      server for the microsoft.com domain. Similarly, Great 
                      Britain probably wants to administrate the uk top-level 
                      domain, Australia wants to administrate the au domain, 
                      For this reason,  DNS system is a distributed database. 
                      Microsoft is completely responsible for dealing with the 
                      name server for microsoft.com -- it maintains the machines
                      that implement its part of the DNS system, and Microsoft 
                      can change the database for its domain whenever it wants 
                      to because Microsoft owns its domain name servers. 
                      Every domain has a domain name server somewhere that 
                      handles its requests, and there is a person maintaining 
                      the records in that DNS. This is one of the most amazing 
                      parts of
                      the DNS system -- it is completely distributed throughout 
                      the world on millions of machines administered by millions
                      of people, yet it behaves like a single, integrated 
                      database! 
                           
Domain Name System    is a distributed database,  
                      are central name servers at core of  system 
                      Someone maintain these central name servers to 
                      avoid conflicts and duplication. 
                      In 1993, U.S. Department of Commerce, in conjunction 
                      with several public and private entities,created InterNIC 
                      to maintain a central database 
                      that contains all the registered domain names and 
                      associated IP addresses in U.S. 
                      (other countries maintain their own NICs
                      (Network Information Centers) 
                      Network Solutions, a member of InterNIC, was
                      chosen to administer and maintain growing number of 
                      Internet domain names and IP addresses. 
                      This central database is copied to Top Level
                      Domain (TLD) servers around the world 
                      and creates primary routing tables 
                      used by every computer that connects to the Internet. 
                      Until recently, Network Solutions was  only company 
                      provided domain names. 
                      However, to ensure that Network Solutions did not become
                      monopoly, U.S. government decided that other 
                      companies should also be allowed to sell domain names. 
                      While these other companies (known as registrars)
                      provide domain names and maintain DNS  servers,
                      Network Solutions still maintains central  database 
                      to ensure that there are no duplicates. 
                      In U.S., you pay Network Solutions an annual fee 
                      to maintain your domain name in central name server.
Domain Name Server    A computer that converts host names, such as 
                      rohan.sdsu.edu to its corresponding IP Address, such as 
                      191.130.1.10. An SDSU computer provides this service any 
                      time 
                      mail is sent or received and permits users to use TELNET 
                      and FTP between SDSU and other sites. 
DOS                   Disk Operating System. The operating system used on IBM 
                      personal computers and compatible machines. 
Dotted Decimal        Notation 
                      The convention for writing 32-bit IP Addresses as a set 
                      of four 8-bit numbers written in base 10 with periods 
                      separating them. 
Down-Sampling         The reduction in resolution of an image, necessitating a 
                      loss in detail. 
Download              To retrieve a file from another computer using a modem. 
dpi                   Dots Per Inch. A measure of resolution of a printer, 
                      scanner, or monitor. It refers to number of dots in a 
                      one-inch line. The more dots per inch, higher 
                      resolution. 
Driver                A piece of software that tells computer how to operate 
                      an external device, such as a printer, hard disk, CD-ROM 
                      drive, or scanner. For instance, you can't print 
                      unless you have a printer driver. Hard disk drivers are 
                      invisible files that are loaded into memory when you 
                      start computer, while scanner drivers are usually 
                      plug-ins 
                      accessed from within a particular application. 
Drum Scanner          Early drum scanners separated scans into CMYK data, 
                      recording these directly onto film held on a second 
                      rotating drum. 
DTP                   Desktop Publishing. 
Dual Homed Gateway    a system that has two or more network
                      interfaces, eachconnected to a different network. In
                      firewall configurations,  acts to block or
                      filter traffic trying to pass between  networks.
Dump                  Back-up of data. 
Duplex (Full, Half)   Full duplex is data is flowing in both directions at 
                      same time. When Remote echo is ON communication is 
                      occurring in full duplex. Half Duplex has data moving in 
                      only 
                      one direction at a time (Local echo is ON). 
DXF                   Drawing Interchange Format used for Macintosh graphic 
                      files. The standard file-exchange format for 3-D and CAD 
                      programs. 
Dye Sublimation       A printing process using small heating elements to 
                      evaporate pigments from a carrier film, depositing these 
                      smoothly onto a substrate. 
EARN                  European Academic Research Network. 
                      Echo (Local, Remote) 
                      Local echo ON causes all transmitted data to be sent to 
                      screen of sending computer. Remote echo ON causes 
                      everything that remote computer (the one you 
                      are communicating with) transmits to be duplicated on 
                      your computer's screen. See Duplex. 
Echo (Local, Remote)  Local echo ON causes all transmitted data to be sent to 
                      screen of sending computer. Remote echo ON causes 
                      everything that remote computer (the one you 
                      are communicating with) transmits to be duplicated on 
                      your computer's screen. See Duplex. 
EBCDIC                Extended Binary-Coded Decimal Interchange Code. A 
                      standard character-to-number encoding used primarily by 
                      IBM computer systems. See ASCII. 
E-mail                Electronic Mail. Private messages sent between users on 
                      different computers, either over a network or via a modem 
                      connection to an on-line service or BBS. 
E-mail bombs          An e-mail bomb is usually a personal  
                      attack. Someone sends you the same e-mail hundreds or 
                      thousands of times until your e-mail system cannot  
                      accept any more messages.  
Encoding              File transfer formatting that enables encrypted, 
                      compressed or binary files to be transferred without 
                      corruption or loss of data. 
Encryption            A way of coding information in a file or e-mail message 
                      so that if it is intercepted by a third party as it 
                      travels over a network it cannot be read. 
Encrypting Router     see Tunneling Router and Virtual Network Perimeter.

EPS                   Encapsulated PostScript. An EPS file usually has two 
                      parts: a PostScript (text) description that tells a 
                      PostScript printer how to output resolution-independent 
                      image, 
                      and (optionally) a bit-mapped PICT image for on-screen 
                      previews. (EPS files without a PICT preview is usually 
                      displayed as a gray rectangle.) EPS files generally 
                      can't be edited, even by program that created them 
                      (Illustrator files are exceptions). 
                      EPS 5 
                      Another term used for DCS. 
ERIC                  An index to educational journal articles and documents 
                      collected by national clearing houses for educational 
                      information. It provides summaries of articles and 
                      documents, and contains citations back to 1966. 
Ethernet              An IEEE 802.3 standard data link layer which can operate 
                      over several different media including fiber optic, 
                      coaxial cable and twisted-pair cable. This 10 
                      million-bit-per-second networking scheme is widely used 
                      on campus because it can network a wide variety of 
                      computers; it is not proprietary; and components are 
                      widely available from many commercial sources. 
                      Executable File 
                      Refers to a file that is a program. Executables in DOS 
                      and Windows usually have an .exe or a .com extension. In 
                      UNIX and Macintosh environments, executable files 
                      can have any name. 
Executable File       Refers to a file that is a program. Executables in DOS 
                      and Windows usually have an .exe or a .com extension. In 
                      UNIX and Macintosh environments, executable files 
                      can have any name. 
External viewer       Program used for presenting graphics, audio and movies 
                      while browsing World Wide Web pages via a Web client 
                      program. Helper applications is another term for these 
                      external programs. 
                      F or Return to Quick Index 
FAQ                   Frequently Asked Questions. A document that covers a 
                      topic of general concern to many users. FAQs are a good 
                      way for new users to get information on various 
                      aspects of Internet. 
FDDI                  Fiber Distributed Data Interface. An emerging standard 
                      for network technology based on fiber optics that has 
                      been established by American National Standards 
                      Institute (ANSI). FDDI specifies a 100-million bit per 
                      second data rate. 
File                  A collection of information on a disk, usually a document 
                      or a program, that's lumped together and called by one 
                      name. 
File Permissions      When you place files on a UNIX system you can assign 
                      files various levels of permission, specifying who can 
                      access them, and what type of access they can have. 
File Server           A computer that shares its resources, such as printers 
                      and files, with other computers on network. An example of 
                      this is a Novell NetWare Server which shares its 
                      disk space with a workstation that does not have a disk 
                      drive of its own. 
Film Recorder         Used in reference to color transparency recording 
                      devices, and sometimes also to imagesetters. 
Filter                A piece of software that an application uses for 
                      file-format conversion or special effects. PageMaker, for 
                      example, has a filter that lets it import Microsoft Word 
                      files, 
                      while Photoshop has dozens of filters for special effects 
                      (such as image blurring). Filters can be part of main 
                      application or external programs called plug-ins. 
Finger                A program that displays information about someone on 
                      internet. 
firewall              is simply a program or hardware device that
                      filters the information coming through the Internet  
                      connection into your private network or computer system. 
                      If an incoming packet of information is flagged by the  
                      filters, it is not allowed through.  
                      Firewalls use one or more of three methods to control  
                      traffic flowing in and out of the network: 
firewall will sniff   (search through) each packet
                      of information for an exact match of the text listed
                      in the filter. For example,  could instruct the
                      firewall to block any packet with the word "X-rated"   
Firewall              enforces a boundary between two or more networks.
Firewall              A mechanism that isolates a network from rest of 
                      Internet, permitting only specific traffic to pass in and 
                      out. 
Flaming/Flame War     Reacting to someone's newsgroup posting or e-mail in a 
                      hostile manner by publicly chastising person or 
                      bombarding person with nasty e-mail. 
                      Flatbed Scanner 
                      Any scanning device that incorporates a flat transparent 
                      plate, on which original images are placed for scanning. 
                      The scanning process is linear rather than rotational. 
                      Floating-point Processor 
                      A special chip that handles sophisticated calculations, 
                      such as those used in spreadsheets, CAD, and scientific 
                      programs. 
Flatbed Scanner       Any scanning device that incorporates a flat transparent 
                      plate, on which original images are placed for scanning. 
                      The scanning process is linear rather than rotational. 
Floating-point        Processor 
                      A special chip that handles sophisticated calculations, 
                      such as those used in spreadsheets, CAD, and scientific 
                      programs. 
Folder                An object that can hold other objects, such as other 
                      folders and files. 
Font                  The software that creates a typeface on a computer 
                      screen. 
Format                To initialize a disk to prepare it for use. The disk is 
                      checked for errors and organized so that data can be 
                      recorded and retrieved. Formatting a used disk erases any 
                      previously stored information. 
FPO                   For Position Only. A low resolution image placed in a 
                      document to indicate where final version is to be 
                      positioned. 
Fragmentation         A condition where parts of a file are stored in different 
                      locations on a disk. When a file is fragmented, drive's 
                      read/write head has to jump from place to place to read 
                      data; if many files are fragmented, it can slow drive's 
                      performance. 
Frame-grabbing        System 
                      A combination of hardware and software, designed to 
                      capture individual frames from video clips for further 
                      digital manipulation, or consecutive replay on computer 
                      platforms. 
FTP                   (File Transfer Protocol) - used to download   
                      and upload files    
FTP                   File Transfer Protocol. The Internet standard high-level 
                      protocol for transferring files from one computer to 
                      another across network. 
FTP site              A computer which stores files that can be retrieved using 
                      FTP. FTP sites which allow anyone to retrieve files 
                      (without having an account on that computer) are known 
                      as Anonymous FTP sites. 
                      G or Return to Quick Index 
Gamma Correction      The correction of tonal ranges in an image, normally by 
                      adjustment of tone curves. 
Gamut                 The limited range of colors provided by a specific input 
                      device, output device or pigment set. 
Gang Scanning         Sequential scanning of multiple originals using same 
                      previously defined exposure setting for each. 
Gateway               A special-purpose dedicated computer that attaches to two 
                      or more disparate networks and converts data packets from 
                      one form to another. 
GB                    Gigabyte. A unit of data storage size which represents 
                      10^9 (one billion) characters of information. 
Gb                    Gigabit. 10^9 bits of information (usually used to 
                      express a data transfer rate; as in, 1 Gigabit/second = 
                      1Gbps). 
GCG                   (Grey Component Replacement) 
                      A technique for replacing all neutral tones of an image 
                      with an appropriate amount of black. 
GIF                   Graphic Interchange Format (pronounced jiff). A file 
                      compression format developed by CompuServe for 
                      transferring graphic files to and from on-line services. 
Gigabyte              1,024 megabytes, or 1,048,576 kilobytes of digital data. 
gopher                A consistent user interface and gateway into many on-line 
                      white pages and other address databases. 
Graphical User        Interface (GUI) 
                      The graphical visual representation of working 
                      environment that presents elements of your computer as 
                      objects on a desktop. 
Grey Balance          The balance between CMY colorants required to produce 
                      neutral greys without a color cast. 
Grey Levels           Discrete tonal steps in a continuous tone image, inherent 
                      to digital data. Most CT images will contain 256 grey 
                      levels per color. 
Greyscale             A continuous tone image comprising black, white, and grey 
                      data only. 
                      H or Return to Quick Index 
Hacker                Slang term for a technically sophisticated computer user 
                      who enjoys exploring computer systems and programs, 
                      sometimes to point of obsession. 
Halftone              A simulation of continuous tones by use of black or 
                      overlapping process color dots of varying size or 
                      position. 
Halftoning Factor     See quality factor. 
Halo                  A light line around object edges in an image, produced by 
                      USM (sharpening) technique. 
Handle                Unique character string identifier assigned to each entry 
                      in NIC WHOIS database. 
Handshaking           The process computers and modems go through in order to 
                      establish a connection and agree on speed and protocols 
                      for data transmission. 
Hayes Compatible      A modem is considered Hayes Compatible if it supports 
                      Hayes command set (a language used to communicate with 
                      and control a modem). 
Header                The portion of a packet, preceding actual data, 
                      containing source and destination addresses, error 
                      checking and other fields. A header is also part of an 
                      electronic 
                      mail message that precedes body of a message and 
                      contains, among other things, message originator, date 
                      and time. 
High Key              A light image that is intentionally lacking in shadow 
                      detail. 
Highlight             The lightest tones in an image. A spectral highlight is a 
                      bright, reflected light source. 
Histogram             A chart displaying tonal ranges present in an image as a 
                      series of vertical bars. 
Home Page             The document that is displayed when you first open a web 
                      client program. Also, commonly used to refer to first 
                      document you come to in a collection of documents 
                      on a Web site. 
Host                  The main computer system to which users are connected. 
                      Hostname 
                      Name which officially identifies each computer attached 
                      to Internet. 
Host-based Security   technique of securing an individual system from attack. 
                      is operating system and version dependent.

otlist               A file containing lists of Internet Web pages, enabling 
                      you to easily access your favorite Web pages. 
HP                    Hewlett Packard. 
HTML                  HyperText Markup Language. A system for tagging various 
                      parts of a Web document that tells Web client programs 
                      how to display document's text, links, 
                      graphics and attached media. 
HTTP                  (Hyper Text Transfer Protocol) - used for 
                      Web pages 
Hue                   The color of an object perceived by eye due to fact 
                      that a single or pair of RGB primary colors predominates. 
Hypermedia            Describes hypertext in which various types of data can be 
                      stored - sound, images, video and so on - as regular 
                      text. 
Hypertext             A text-linking strategy that lets you jump between 
                      related information in a document by clicking on a button 
                      or highlighted word. On-line help systems often use 
                      hypertext links, as do some programs designed for 
                      electronic distribution of documents. 
I/O                   Input/Output. 
I-beam                The blinking vertical line that shows point at which 
                      text or graphics will be inserted. 
IBM                   International Business Machines Corporation. 
ICMP                  (Internet Control Message Protocol) - used   
                      by a router to exchange the information with  
                      other routers  

ICMP redirects        and redirect bombs?
                      An ICMP Redirect tells recipient system 
                      to over-ride something in its routing table. 
                      legitimately used by routers to tell hosts that 
                      host is sending it to  wrong router. 
                      wrong router sends  host back 
                      an ICMP Redirect packet that tells host 
                      what correct route should be. 
                      If forge ICMP Redirect packets, 
                      and if target host pays attention to them, 
                      can alter routing tables on host 
                      possibly subvert security of  host 
                      causing traffic to flow a path
                      ICMP Redirects also may be employed
                      for denial of service attacks, 
                      where a host is sent a route that loses it connectivity, 
                      or sent ICMP Network Unreachable packet 
                      telling it can no longer access a particular network.
                      Many firewall builders screen ICMP traffic 
                      from their network, since it
                      limits ability of outsiders to ping hosts, 
                      or modify their routingtables.
                      Before you decide to completely block ICMP, 
                      should be aware of how TCP protocol does 
                      ``Path MTU Discovery'', 
                      to make certain that you don't
                      break connectivity to other sites. 
 
Icon                  A graphic symbol, usually representing a file, folder, 
                      disk or tool. 
Image Map             A graphic divided into regions or "hotspots". When a 
                      particular region is clicked, it calls up a web page that 
                      has been associated with that particular region. 
Imagesetter           A device used to record digital data (images and text) 
                      onto monochrome film or offset litho printing plates by 
                      means of a single or multiple intermittent light beams. 
                      Color 
                      separated data is recorded as a series of slightly 
                      overlapping spots to produce either solid areas of 
                      line-art or halftone dots for printing continuous tones. 
Import                To bring data into a document from another document, 
                      often generated by a different application. 
Inactive Window       A window that is open but is not top window. 
Infopath              Internet gopher for University of California at San 
                      Diego. 
Information           Technology 
                      Includes matters concerned with furtherance of computer 
                      science and technology, design, development, installation 
                      and implementation of information systems and 
                      applications. 
Initializing          (formatting) 
                      Setting up a disk (any kind) to receive information. When 
                      a disk is initialized (formatted), its magnetic media is 
                      divided into tracks and sectors, and structure files that 
                      your 
                      computer uses to keep track of data are created. 
Inline images         Graphics that are contained within a document's textual 
                      information. In a Web document, these graphics can either 
                      be loaded automatically when page is accessed 
                      or loaded manually by clicking on image's icon. 
Insider Attack        An attack originating from inside a protected network.
Installer             A utility that copies system software or an application 
                      from floppy disks or a CD-ROM to your hard disk. An 
                      Installer may also decompress new files, remove 
                      obsolete files, place extensions and control panels in 
                      their proper folders, and/or create new folders. 
Interface             The way a computer interacts with a user or a peripheral. 
                      Internet 
                      The Internet (note capital I) is largest internet in 
                      world. It is a three level hierarchy composed of backbone 
                      networks (e.g., NSFNET, MILNET), mid-level 
                      networks, and stub networks. The Internet is a 
                      multiprotocol internet. 
Interpolation         In image manipulation context, this is increase of 
                      image resolution by addition of new pixels throughout 
                      image, colors of which are based on 
                      neighboring pixels


Internet domain names registered and  maintained? 
                      Since its beginning in  1969, the Internet has grown from
                      four host computer systems to tens of millions. , 
                      just because nobody owns the Internet, it doesn't mean it 
                      is not monitored and maintained in different ways. 
                      Internet Society, a non-profit 
                      group established in 1992, oversees the formation of  
                      policies and protocols that define
                      how we use and interact with  Internet. 
                      When Internet was in its infancy, only connections 
                      by providing  IP (Internet Protocol) address 
                      typical IP address might be 216.27.22.162. T
                      first solution to was  text file maintained by  
                      Network Information Center 
                      that mapped names to IP addresses. Soon 
                      this text file became so large 
                      it was too cumbersome to manage. 
                      1983,University of Wisconsin created Domain Name System 
                      DNS), which maps text names to IP addresses. 
                      only need to remember www.howstuffworks.com, 
                      instead of 216.27.22.162. 
. 
Interrupt             A brief interruption of computer's activity so that an 
                      urgent task can be performed. 
Intrusion Detection   Detection of break-ins or break-in attempts 
                      either manually or via software expert systems 
                      that operate on logs or other information
                      available on the network.
IP                    (Internet Protocol) - the main delivery  
                      system for information over the Internet 
IP                    Internet Protocol is standard that allows dissimilar 
                      hosts to connect to each other through Internet. This 
                      protocol defines IP datagram as basic unit of 
                      information sent over Internet. The IP datagram consists 
                      of an IP header followed by a message. 

IP addresses          Each machine on the Internet is   
                      assigned a unique address called an IP address. IP  
                      addresses are 32-bit numbers, normally expressed as
                      four "octets" in a "dotted decimal number." A typical  
                      IP address looks like this: 216.27.61.137. For
                      example, if a certain IP address outside the company 
                      is reading too many files from a server, the firewall 
                      can block all traffic to or from that IP address.  
IP Addresses Work     each machine is assigned a unique address called 
                      an IP Address. 
                      IP stands for Internet protocol, and these addresses are
                      32-bit numbers normally expressed as 4 "octets" in a 
                      "dotted decimal number". A typical IP address looks like 
                      this: 
                                216.27.61.137
                      The four numbers in an IP address are called octets 
                      because they can have values between 0 and 255 (28 
                      possibilities per octet). 
                      
                      Every machine on the Internet has a unique IP address. 
                      A server has static IP address that does not change often.
                      A home machine that is dialing up through a modem often
                      has an IP address that is assigned by the ISP when you 
                      dial in. That IP address is unique for your session but 
                      may be different the next time you dial in. 
                      can view your current IP address with command 
                      WINIPCFG.EXE. On a 
                      UNIX machine type nslookup along with a machine
                      name (like www.howstuffworks.com -- e.g. "nslookup 
                      www.howstuffworks.com") to display the IP address of the 
                      machine (use  command hostname to learn name of your
                      machine). [For more information on IP addresses see IANA] 
                      As far as the Internet's machines are concerned, an IP 
                      address is all that you need to talk to a server. For 
                      example, in your browser you can type the URL 
                      http://216.27.61.137 and
                      you will arrive at the machine that contains the web 
                      server for How Stuff Works. Domain names are strictly a 
                      human convenience. 

IP Address            Network addresses are usually of two types: (1) physical 
                      or hardware address of a network interface card; for 
                      Ethernet this 48-bit address might be 
                      0260.8C00.7666. The hardware address is used to forward 
                      packets within a physical network. (2) The logical or IP 
                      Address is used to facilitate moving data between 
                      physical networks and is made up of a network number, a 
                      subnetwork number, and a host number. All Internet 
                      addresses at SDSU have a network number of 130.191, a 
                      subnet number in range of 1-254, and a host number in 
                      range of 1-254. 
IP Datagram           The basic unit of information passed across Internet. An 
                      IP Datagram is to Internet as a hardware packet is to a 
                      physical network. It contains a source and 
                      destination address along with data. Large messages are 
                      broken down into a sequence of IP Datagrams. 
IP Spoofing           An attack whereby a system attempts to illicitly 
                      impersonate another system  using its IP network address.
IPSplicing/Hijacking  An attack whereby an active, established, session is 
                      intercepted and co-opted by the attacker. IP Splicing 
                      attacks may occur after an authentication has been made, 
                      permitting the attacker to assume the
                      role of an already authorized user. Primary protections 
                      against IP Splicing rely on encryption 
                      at the session or network layer.

IRC                   Internet Relay Chat. A program that allows you to carry 
                      on "live" conversations with people all over world by 
                      typing messages back and forth across Internet. 
ISAAC                 Information System for Advanced Academic Computing. 
                      Serves as a clearinghouse for information about use of 
IBM-compatible        hardware and software as aids to 
                      instruction and research in higher education. Membership 
                      is free to all students, faculty, and staff at these 
                      institutions. 
ISO                   International Organization for Standardization, group 
                      that developed OSI protocols. 
ISP                   Internet Service Provider. A company that provides access 
                      to Internet. A service provider can offer simple dial-up 
                      access, SLIP/PPP access, or a dedicated line. 
IT8                   Industry standard color reference target used to 
                      calibrate input and output devices. 
ITV                   Interactive Television. 
Java                  An object-oriented programming language to create 
                      executable content (i.e. self-running applications) that 
                      can be easily distributed through networks like Web. 
JPEG                  Joint Photographic Experts Group is a graphic file format 
                      that has a sophisticated technique for compressing 
                      full-color bit mapped graphics, such as photographs. 
                      K or Return to Quick Index 
KB                    KiloByte. A unit of data storage size which represents 
                      10^3 (one thousand) characters of information. 
Kb                    Kilobit. 10^3 bits of information (usually used to 
                      express a data transfer rate; as in, 1 Kilobit/second = 
                      1Kbps = 1Kb). 
Kermit                An error-checking file-transfer protocol used to copy 
                      files from one computer to another. Also name given to 
                      public domain software distributed by Columbia 
                      University, which supports this protocol. 
Kernel Size           The number of pixels sampled as a unit during image 
                      manipulation and sharpening processes. 
Keyword               Specified words used in text search engines. 
                      Kilobyte (Kb) 
                      1,024 bytes of digital data. 
                      L or Return to Quick Index 
LAN                   Local Area Network. A network of directly-connected 
                      machines (located in close proximity), providing high 
                      speed communication over physical media such as fiber 
                      optics, coaxial cable, or twisted pair wiring. 
Laser Printer         Although a number of devices employ laser technology to 
                      print images, this normally refers to black-and-white 
                      desktop printers, which use dry toner, xerographic 
                      printing process. 
Laserdisc             A 12-inch disk that's similar to an audio CD but holds 
                      visual images (such as high-quality movies) as well as 
                      music. Also called a videodisc. 
                      Links 
Least Privilege       Designing operational aspects of a system to operate with 
                      a minimum
                      amount of system privilege. This reduces the authorization 
                      level at
                      which various actions are performed and decreases the 
                      chance that a
                      process or user with high privileges may be caused to  
                      perform
                      unauthorized activity resulting in a security breach.
                      Synonymous with anchors, hotlinks and hyperlinks. 
Line Art              Images containing only black and white pixels. Also known 
                      as bilevel images. The term line art is sometimes used to 
                      describe drawings containing flat colors without 
                      tonal variation. 
LION                  Library Internet Online Network. A menued front-end 
                      system at SDSU that allows access to a number of 
                      databases such as library on-line catalogs, periodical 
                      indexes, and Internet gophers. 
LISTSERV              A distribution list management package whose primary 
                      function is to operate mailing lists. It allows groups of 
                      computer users with a common interest to communicate 
                      among themselves. 
Local system          The system you are using. Interactions between your 
                      computer and another computer on Internet are sometimes 
                      described using terms "local" and "remote" 
                      systems. The local system is your computer and remote 
                      system is other computer. 
LOCIS                 Library of Congress catalog system. The Library of 
                      Congress has an extensive and useful congressional 
                      legislation system that you can use to look up bills that 
                      are in 
                      Congress, as well as having nearly any book ever 
                      published in United States. 
Login                 The account name used to access a computer system. 

Logging               The process of storing information about events that 
                      occurred on the
                      firewall or network.
Log Retention         How long audit logs are retained and maintained.
Log Processing        How audit logs are processed, searched for key events, or 
                      summarized.

Lossy                 Image compression that functions by removing minor tonal 
                      and/or color variations, causing visible loss of detail 
                      at high compression ratios. 
Low Key               A dark image that is intentionally lacking in highlight 
                      detail. 
LPI/LPCM              Lines per inch or per centimeter. Units of measurement 
                      for screen ruling. 
Lurker                Slang term for someone who regularly reads newsgroup, 
                      BBS, or mailing list discussions, but rarely participates 
                      in them. 
Lynx                  A type of browser designed to work with text-only 
                      Internet connections like dial-up UNIX shell accounts. 
LZW                   The Lempel-Ziv-Welch image compression technique. 
                      M or Return to Quick Index 
Macros                To simplify complicated procedures, many  
                      applications allow you to create a script of commands  
                      that the application can run. This script is known as 
                      a macro. Hackers have taken advantage of this to
                      create their own macros that, depending on the
                      application, can destroy your data or crash your
                      computer.     
Mail Merge            The merging of database information (such as names and 
                      addresses) with a letter template in a word processor, in 
                      order to create personalized letters. 
Mailing List          A list of Email users who are members of a group. A 
                      mailing list can be an informal group of people who share 
                      Email with one another, or it can be a more formal 
                      LISTSERV group which discusses a specific topic. 
Mainframe             A large, multi-tasking computer that is used by many 
                      users. 
Marvel                Machine-Assisted Realization of Virtual Electronic 
                      Library. The Library of Congress' gopher. It presents 
                      information about Library of Congress such as 
                      facilities and services, reading rooms, copyright, 
                      services to libraries and publishers, etc., as well as 
                      other Internet resources. 
Math Coprocessor      Another name for a floating-point processor. 
                      Matrix 
                      This often refers to a 2-dimensional array of CCD 
                      elements. 
Medium                The material used to support transmission of data. 
                      Examples include twisted-pair wire, coaxial cable, 
                      optical fiber, or electromagnetic wave (microwave). 
Megabit (Mb)          Megabit. 10^6 bits of information (usually used to 
                      express a data transfer rate; as in, 1 Megabit/second = 
                      1Mbps). 
Megabyte (MB)         MegaByte. A unit of data storage size which represents 
                      10^6 (one million) characters of information. 
Megahertz (MHz)       A million cycles (occurrences, alterations, pulses) per 
                      second. Used to describe speed at which a computer's 
                      processor (or CPU) operates. 
Melvyl                An on-line catalog system containing books, music scores 
                      and recordings, audiovisual materials, maps, and computer 
                      files from UC libraries and California State 
                      Library. Also featured are periodicals from several 
                      sources. 
Memory                In general, another word for dynamic RAM, chips where 
                      computers store system software, programs, and data you 
                      are currently using. Other kinds of computer 
                      memory you may encounter are parameter RAM (PRAM), video 
                      RAM (VRAM), and static RAM (SRAM). Most computer memory 
                      is volatile, that is, its contents are 
                      lost when computer shuts down. 
Menu                  A list of commands. 
                      Menu Bar 
                      The horizontal bar that contains names of available 
                      menus. The menu bar is located below title bar. 
Message               A collection of data that is ordered according to rules 
                      of a given protocol suite, such that it is intelligible 
                      to sending and receiving software. 
MHz                   Megahertz. A million cycles (occurrences, alterations, 
                      pulses) per second. Used to describe speed at which a 
                      computer's processor (or CPU) operates. A 25-MHz 
                      processor can handle 25 million operations per second. 
MIDI                  Musical Instrument Digital Interface. A technology that 
                      enables a computer to record and play musical 
                      performance. 
                      Midtone 
                      The middle range of tones in an image. 
MILNET                Military Network. A network used for unclassified 
                      military production applications. It is part of DDN and 
                      Internet. 
MIME                  Multi-purpose Internet Mail Extensions. A format 
                      originally developed for attaching sounds, images and 
                      other media files to electronic mail, but now also used 
                      with 
                      World Wide Web applications. 
MIME mappings         A list of file extensions and types of files they belong 
                      to. When server sends an HTTP reply, it sends a 
                      type/subtype header according to requested file's 
                      extension. 
                      MIME type/subtype 
                      An HTTP header sent with a reply that determines how a 
                      client will view or use message. The MIME type tells 
                      general type of document, such as image or 
                      application, and subtype tells specific type such as 
                      GIF or ZIP. 
MIPS                  Millions of Instructions Per Second. 
Mirror site           An FTP site that is created after contents of an 
                      original FTP archive server are copied to it. Usually, 
                      mirror sites use larger and faster systems than original, 
                      so it's 
                      easier to obtain material from mirror. Mirror sites are 
                      usually updated daily, so everything on original is also 
                      at mirrors. Tip - Always use mirror site that is 
                      physically closest to you. 
Modem                 A device which converts digital signals into analog 
                      signals (and back) for transmission over telephone lines 
                      (modulator and demodulator). 
Moire                 A repetitive interference pattern caused by overlapping 
                      symmetrical grids of dots or lines having differing pitch 
                      or angle. 
Monochrome            Single-colored. An image or medium displaying only 
                      black-and-white or greyscale information. Greyscale 
                      information displayed in one color is also monochrome. 
                      Motherboard 
                      The heart, soul, and brains of a computer. This plastic 
                      board resembles a miniature city, but its buildings are 
                      actually chips for things like processing, RAM, and ROM, 
                      and tiny roads connecting them are circuit traces. Also 
                      called logic board. There are no fatherboards or 
                      sonboards, but see daughterboard. 
Mottling              A texture similar to orange peel sometimes caused by 
                      sharpening. It is particularly visible in flat areas such 
                      as sky or skin. 
MOV                   A file extension found on World Wide Web that denotes 
                      that file is a movie or video in QuickTime format. 
MPEG                  Moving Pictures Expert Group. MPEG is an international 
                      standard for video compression and desktop movie 
                      presentation. You need a special viewing application to 
                      run 
                      MPEG movies on your computer. MPEG II is a newer 
                      standard for broadcast-quality video. 
Multimedia            Any presentation or software program that combines 
                      several media, such as graphics, sound, video, animation, 
                      and/or text. 
Multiplex             The division of a single transmission medium into 
                      multiple logical channels supporting many apparently 
                      simultaneous sessions. 
Multitasking          The capability of an operating system to handle multiple 
                      processing tasks, apparently, at same time. 
                      Return to Quick Index 
                      Send comments/suggestions about this web page to 
                      webmaster@rohan.sdsu.edu 
                      SDSU Faculty and Students may send questions about 
                      software on ROHAN or ROHAN UNIX problems to 
                      problems@rohan.sdsu.edu 
                      San Diego State University 
                      This page last modified: November 24, 1998 
                      Glossary of Academic Information 
                      Technology Terms 
                      N or Return to Quick Index 
Native                Software that's written specifically to run on a 
                      particular processor. For example, a program optimized 
                      for a 68K processor runs in native mode on a Quadra, but 
                      it runs 
                      in emulation mode (which is slower on a Power PC-based 
                      Power Mac). Also, file format in which an application 
                      normally saves it documents. The native format is 
                      generally readable only by that application (other 
                      programs can sometimes translate it using filters). 
Navigation Tools      Allows users to find their way around a website or 
                      multimedia presentation. They can be hypertext links, 
                      clickable buttons, icons, or image maps. 
Netiquette            A form of online etiquette. This term refers to an 
                      informal code of conduct that governs what is generally 
                      considered to be acceptable way for users to interact 
                      with 
                      one another online. 
news                  A term often used to denote USENET news, a popular forum 
                      for discussion on Internet. 
newsgroup             A discussion group, usually found on USENET news. Each 
                      group devotes its discussions to a specific topic. 
newsreader            A software program that lets you subscribe to newsgroups 
                      as well as read and post messages to them. 
news server           A machine that contains a number of USENET newsgroups. 
                      Also referred to a NNTP server. 
Netware               The chief priest of network operating systems. 
Network               In general, a group of computers set up to communicate 
                      with one another. Your network can be a small system 
                      that's physically connected by cables (a LAN), or you 
                      can connect separate networks together to form larger 
                      networks (called WANs). The Internet, for example, is 
                      made up of thousands of individual networks. 
Network-LayerFirewall A firewall in which traffic is examined at the network 
                      protocol packet
                      layer.
network firewall      Generally, protect against unauthenticated
                      interactive logins 
                      they can provide a single ``choke point''
                      where security and audit can be imposed.
NFS                   Network File System. A protocol developed by Sun 
                      Microsystems which allows a computer system to access 
                      files over a network as if they were on its local disks. 
                      This 
                      protocol has been incorporated in products by more than 
                      two hundred companies, and is now a de facto Internet 
                      standard. 
NIC                   Network Information Center. A organization that provides 
                      information, assistance and services to network users. 
NOC                   Network Operations Center. A location from which 
                      operation of a network or internet is monitored. 
                      Additionally, this center usually serves as a 
                      clearinghouse for 
                      connectivity problems and efforts to resolve those 
                      problems. 
Node                  A computer that is attached to a network; sometimes 
                      called a host. 
Noise                 In scanning context, this refers to random, incorrectly 
                      read pixel values, normally due to electrical 
                      interference or device instability. 
Non-lossy             Image compression without loss of quality. 
NSFNET                National Science Foundation Network. The NSFNET is a high 
                      speed network of networks which is hierarchical in 
                      nature. At highest level is a backbone network 
                      which spans continental United States. Attached to that 
                      are mid-level networks and attached to mid-levels are 
                      campus and local networks. NSFNET also has 
                      connections out of U.S. to Canada, Mexico, Europe, and 
                      Pacific Rim. The NSFNET is part of Internet. 
                      O or Return to Quick Index 
                      Object-oriented 
                      Generally used to describe an illustration or font file 
                      as being created by mathematical equations. Also see 
                      Bit-map. 
OCR                   Optical Character Recognition. A technology that lets you 
                      scan a printed page (with a scanner) and convert it into 
                      text document that you can edit in a word processor. 
Offset lithography    A high-volume, ink-based printing process, in which ink 
                      adhering to image areas of a lithographic plate is 
                      transferred (offset) to a blanket cylinder before being 
                      applied 
                      to paper or other substrate. 
                      Network Operations Center. A location from which 
On-line               Actively connected to other computers or devices. You're 
                      on-line when you've logged on to a network, BBS, or 
                      on-line service. A device such as a printer is on-line 
                      when it's turned on and accessible to a computer. If 
                      you're not on-line then you're off-line. 
On-line Service       A commercial service that (for a price) provides goodies 
                      such as e-mail, discussion forums, tech support, software 
                      libraries, news, weather reports, stock prices, plane 
                      reservations, even electronic shopping malls. To access 
                      one, you need a modem. Popular on-line services include 
                      America Online, CompuServe, and Prodigy. 
Operating System      Software that supervises and controls tasks on a 
                      computer. 
Operating system bugs Like applications, some     
                       operating systems have backdoors. Others provide
                      remote access with insufficient security controls or
                      have bugs that an experienced hacker can take    
                      advantage of
Optical Resolution    In scanning context, this refers to number of truly 
                      separate readings taken from an original within a given 
                      distance, as opposed to subsequent increase in 
                      resolution (but not detail) created by software 
                      interpolation. 
Optical Video Disc    Compact discs which use lights to read information. 
OSI                   Open Systems Interconnection, a set of standard protocol 
                      grouped into seven layers: physical, data link, network, 
                      transport, session, presentation, and application 
                      layers. 
                      P or Return to Quick Index 
PAC                   Public Access Catalog. The SDSU University Library's 
                      on-line catalog which lists books held here and journals 
                      subscribed to (but not their contents. It also 
                      provides information on circulation status, books and 
                      journals ordered but not yet received, receipt of journal 
                      issues, and more. 
Packet                The unit of data sent across a packet switching network. 
                      While some Internet literature use term to refer 
                      specifically to data sent across a physical network, 
                      other 
                      literature views Internet as a packet switching network 
                      and describes IP Datagrams as packets. 
Packet filtering      Packets (small chunks of data) are  
                      analyzed against a set of filters. Packets that make  
                      it through the filters are sent to the requesting
                      system and all others are discarded.     
Packet-switching      Data transmission process, utilizing addressed packets, 
                      whereby a channel is occupied only for duration of packet 
                      transmission. SDSUnet is a are packet-switching network. 
Paint                 The oldest and most limited Macintosh graphic file 
                      format, holding only black-and-white bit maps at 72 dpi. 
                      Paint files (file type PNTG) are limited to 8 by 10 
                      inches. 
Parallel              Cable/Parallel Port 
                      A cable used to connect peripheral devices through a 
                      computer's parallel port. A type of port that transmits 
                      data in parallel (several bits side by side). 
                      Parameter 
                      A word, number, or symbol that is typed after a command 
                      to further specify how command should function. 
Parity                A check bit used to make sum of bits in a unit of data 
                      either even or odd (including parity bit). A unit of data 
                      that is 8 bits long would have no parity, and a unit 
                      of data 7 bits long would have an even parity bit to make 
                      an 8 bit word. Parity is used to check a unit of data for 
                      errors during transmission through phone lines or null 
                      modem cables. 
Paste                 To insert information from Clipboard. Information can be 
                      pasted multiple times. 
Path                  A route used in finding, retrieving, and storing files on 
                      a disk. The course leading from root directory of a drive 
                      to a particular file. 
PERL                  The Practical Extraction and Report Language. An 
                      interpreted language for CGI scripts. 
PCMCIA                A standard format for credit-card-size expansion cards, 
                      used to add features to laptop computers, hand-held 
                      computers, and desktop computers. The acronym stands 
                      for Personal Computer Memory Card International 
                      Association. 
PDF                   Portable Document Format. A PDF file is an electronic 
                      facsimile of a printed document. 
Peer-to-peer          A network setup that allows every computer to both offer 
                      and access network resources, such as shared files, 
                      without requiring a centralized file server. Macintosh 
                      computers utilize this type of network setup. 
Peripheral            A piece of hardware that's outside main computer. It 
                      usually refers to external hardware such as disk drives, 
                      printers, and scanners sold by a third party. 
PERL                  Practical Extraction and Reporting Language. A robust 
                      programming language frequently used for creating CGI 
                      programs on web servers. 
Perimeter-based       Security
                      The technique of securing a network by controlling access 
                      to all entry
                      and exit points of the network.
PICS                  The standard macintosh graphic file format for 
                      animations. Essentially a collection of bit-mapped PICT 
                      images in sequential order, much like movie frames. 
PICT/PICT 2           PICT is standard macintosh graphic file format for 
                      graphics that are cut or copied to Clipboard and for 
                      drawings that won't be output on PostScript printers. 
                      This 
                      format is ideal for on-screen presentations, but page 
                      layout programs sometimes have problems with PICT files. 
                      Files are sometimes called metafiles because they can 
                      contain both bit maps and QuickDraw-based objects. 
Pixel                 Picture element. Digital images are composed of touching 
                      pixels, each having a specific color or tone. The eye 
                      merges differently colored pixels into continuous tones. 
Pixel Skipping        A means of reducing image resolution by simply deleting 
                      pixels throughout image. 
PKZIP/PKUNZIP         A software compression utility for PC. It allows you to 
                      compress or "zip" a file or a number of files into one 
                      archive file in ZIP file format. 
Plug-In               Extends capabilities of a web browser, allowing browser 
                      to run multimedia files. 
PMT                   Photomultiplier tube. The light sensing device generally 
                      used in drum scanners. 

Policy                Organization-level rules governing acceptable use of 
                      computing
                      resources, security practices, and operational procedures
POP                   A server using Post Office Protocol, which holds users' 
                      incoming e-mail until they read or download it.
Ports                 Any server machine makes its services 
                      available to the Internet using numbered ports, one 
                      for each service that is available on the server
                      How Web Servers and the Internet Work for details).   
                      For example, if a server machine is running a Web     
                      (HTTP) server and an FTP server, the Web server would
                      typically be available on port 80, and the FTP server  
                      would be available on port 21. A company might block 
                      port 21 access on all machines but one inside the  
Port                  One of several rendezvous points where TCP/IP connections 
                      can be made on a computer. Ports are numbered, with 
                      several locations reserved for specific types of 
                      network activity, such as telnet on port 23, HTTP traffic 
                      on port 80 and USENET news (NNTP) on port 119. 
Posterization         The conversion of continuous tone data into a series of 
                      visible tonal steps or bands. 
ppi/ppc               Pixels per inch or pixels per centimeter. Units of 
                      measurement for scanned images. 
PPP                   Point-to-Point Protocol. It provides a method for 
                      transmitting packets over serial point-to-point links. 
PRAM                  Parameter RAM (pronounced pee-ram). A small portion of 
                      Mac's RAM set aside to hold basic information such as 
                      date and time, speaker volume, desktop 
                      pattern, and key-board and mouse settings. PRAM is 
                      powered by a battery, so it doesn't lose settings when 
                      you shut down. Sometimes, however, PRAM data 
                      gets corrupted, causing crashes or other problems. 
Primary color         A base color that is used to compose other colors. 
Process Ink Colors    CMYK pigments used in printing processes, chosen to 
                      produce widest range of color mixtures. 
Profile               The color characteristics of an input or output device, 
                      used by a CMS to ensure color fidelity. 
Properties            Information about an object, including settings or 
                      options for that object. For example, you look at 
                      properties of a file for information such as file size, 
                      file type, and file   attributes.
Protocols             The protocol is the pre-defined way that
                      someone who wants to use a service talks with that
                      service. The "someone" could be a person, but more  
                      often it is a computer program like a Web browser.
                      Protocols are often text, and simply describe how the
                      client and server will have their conversation. The
                      http in the Web's protocol. Some common protocols 
                      that you can set firewall filters for include: 
Protocols             When data is being transmitted between two or more 
                      devices something needs to govern controls that keep this 
                      data intact. A formal description of message formats 
                      and rules two computers must follow to exchange those 
                      messages. Protocols can describe low-level details of 
                      machine-to-machine interfaces (e.g., order in 
                      which bits and bytes are sent across wire) or high-level 
                      exchanges between application programs (e.g., way in 
                      which two programs transfer a file across 
                      Internet). 
Proxy ARP             A technique in which one machine, usually a gateway, 
                      answers ARP requests for another machine. By pretending 
                      to be physical network location of another 
                      machine, gateway takes over responsibility of routing 
                      packets destined for other machine. For instance, a 
                      gateway can proxy ARP for addresses that 
                      gateway identifies as being off local network and that 
                      gateway has a route for. The originating computer 
                      receives gateway's proxy ARP reply and sends 
                      datagram on to gateway, which routes datagram to its 
                      actual destination network. 
Proxy                 A software agent that acts on behalf of a user. Typical 
                      proxies accept
                      a connection from a user, make a decision as to whether or 
                      not the user
                      or client IP address is permitted to use the proxy, 
                      perhaps does
                      additional authentication, and then completes a connection 
                      on behalf of
                      the user to a remote destination.
A proxy server        referred to as  application gateway or forwarder 
                      mediates traffic between  protected network and Internet 
                      Proxies  used instead of router-based traffic controls, 
                      prevent traffic from passing directly between networks.
                      proxies contain  logging or support for authentication. 
                      proxies must ``understand'' application protocol  used, 
                      they can also implement protocol specific security 
                      (e.g., an FTP proxy might be configurable 
                      to permit incoming FTP and block outgoing FTP).
Proxy Servers + DMZ   A function that is often combined with a firewall is a 
                      proxy server. The proxy server is used to access 
                      by the other computers. When another computer requests a
                      Web page, it is retrieved by the proxy server and then
                      sent to the requesting computer. The net effect of this
                      action is that the remote computer hosting the Web page 
                      never comes into direct contact with anything on your home
                       network, other than the proxy server. 
                      Proxy servers can also make your Internet access work more
                      efficiently. If you access a page on a Web site, it is
                      cached (stored) on the proxy server. This means that the
                      next time you go back to that page, it normally doesn't  
                      have to load again from the Web site. Instead it loads  
                       instantaneously from the proxy server.   
                      may want to create a DMZ Demilitarized Zone)
                      it really is just an area that is outside  firewall.  
                      Setting up a DMZ is very easy. If you have multiple 
                      computers, you can choose to simply place one of the
                      computers between the Internet connection and the 
                      firewall. Most of the software firewalls available will
                      allow you to designate a directory on the gateway computer
                      as a DMZ.   


Proxy service         Information from the Internet is  
                      retrieved by the firewall and then sent to the 
                      requesting system and vice versa.  
PSN                   Packet Switch Node; a store-and-forward packet switch 
                      (formerly called an IMP). 
Public-domain         Software that has no copyright or fee, which means you 
                      can copy, use, and even alter and sell it. 
Quality Factor        A multiplication factor (between 1 and 2) applied to 
                      output screen ruling to calculate scanning resolution for 
                      optimum output quality. This is also known as halftoning 
                      factor. 
Quarter Tones         Tones between shadow and midtones are known as 3/4 tones 
                      and those between highlight and midtones are known as 1/4 
                      tones. 
Query                 The process by which a web client requests specific 
                      information from a web server, based on a character 
                      string that is passed along. 
QuickTime             A file extension for videos or "movies" (like animations) 
                      compressed using their QuickTime format. 
                      R or Return to Quick Index 
RAM                   Random Access Memory. RAM is most common type of 
                      computer memory, and it's where computer stores system 
                      software, programs, and data you are 
                      currently using. It's formally called dynamic RAM (DRAM) 
                      because it's volatile, that is, contents are lost when 
                      you turn off computer (or crash). It's pronounced 
                      ram and measured in megabytes. 
Raster                A synonym for grid. Sometimes used to refer to grid of 
                      addressable positions in an output device. 
Rel                   Recorder element. The minimum distance between two 
                      recorded points (spots) in an imagesetter. 
Remote system         Another computer on Internet to which you connect. 
                      Interactions between computers are often described using 
                      terms "local" and "remote" systems. The local 
                      system is your computer and remote system is other 
                      computer. 
Res                   A term used to define image resolution instead of ppi. 
                      Res 12 indicates 12 pixels per millimeter. 
Resampling            An increase or reduction in number of pixels in an imge, 
                      required to change its resolution without altering its 
                      size. See also down-sampling and interpolation. 
                      Resolution 
                      In general, this refers to how sharp and clear an image 
                      looks on screen or on paper, and how much detail you can 
                      see. It's usually determined by number of dots (or 
                      pixels) per square inch (the more there are, higher 
                      resolution) and is used to describe printers, monitors, 
                      and scanners. 
RFC                   Request For Comments; technical note series which began 
                      in 1969 describing DARPA and Internet research and 
                      development, particularly in areas of protocol 
                      design and internetworking. Not all (in fact very few) 
                      RFCs describe Internet standards, but all Internet 
                      standards are written up as RFCs. 
RGB                   Red, green, and blue are primary colors of light 
                      perceived by eye. 
RIP                   Routing Information Protocol used by Berkeley UNIX 
                      systems to exchange routing information among a set of 
                      computers attached to a network. RIP packets are sent 
                      and received by a program called routed. 
ROGER                 On-line catalog at UCSD for books and other material in 
                      libraries at University of California at San Diego. 
ROM                   Read-Only Memory. It's like software that's hard-wired 
                      into your computer - basic, permanent information that 
                      tells it things like how to load up operating system 
                      when you turn it on. 
route                 packet takes from source to destination 
                      determined by routers between source and destination. 
                      packet itself only says where it wants to go 
                      ( destination address), 
                      to include information to tells route packet should take 
                      name ``source routing''.
                      an attacker can generate traffic claiming to be 
                      from a system ``inside'' the firewall. 
                      In practice, source routing is very little used. 
                      main legitimate use is in debugging network problems 
                      or routing traffic over specific links for congestion 
                      control for specialized situations.                       
Router                A special purpose computer that attaches to two or more 
                      networks and routes packets from one network to other. A 
                      router uses network layer addresses (such as 
                      IP Addresses) to determine if packets should be sent from 
                      one network to another. Routers send packets to other 
                      routers until they arrive at their final destination. 
rpi                   Rels (recorder elements) per inch. A measurement of 
                      number of discrete steps that exposure units in 
                      imagesetting devices can make per inch. 
RS-232                Interface between Data Terminal Equipment (DTE) and Data 
                      Communications Equipment (DCE) employing Serial Binary 
                      Data Interchange, a standard set by 
                      international standards organization - Consultative 
                      Committee on International Telegraphy and Telephony. The 
                      interface between a terminal to a modem for 
                      transfer of serial data. 
RTF                   Rich Text Format. A file format for text files that 
                      includes formatting instructions. Also called Interchange 
                      Format. 
                      S or Return to Quick Index 
Sampling              The process of converting analog data into digital data 
                      by taking a series of samples or readings at equal time 
                      intervals. 
                      Saturation 
                      The extent to which one or two of three RGB primaries 
                      predominate in a color. As quantities of RGB equalize, 
                      color becomes desaturated towards grey or white. 
Scanner               A device that converts images (such as photographs) into 
                      digital form so that they can be stored and manipulated 
                      on computers. 
Screen Frequency      The number of rows or lines of dots in a halftone image 
                      within a given distance, normally stated in lines per 
                      inch (lpi) or lines per centimeter (lpm). A frequency of 
                      200 lpi 
                      would only be used in high-quality printing. 
                      Screen Ruling 
                      Another term used for screen frequency. 
Screen Saver          A moving picture or pattern that is displayed on screen 
                      when no activity takes place for a specified period of 
                      time. 
                      Scripts 
                      A type of program that consists of a set of instructions 
                      for another application or utility to use. 
Screened Host         A host on a network behind a screening router. The degree 
                      to which a
                      screened host may be accessed depends on the screening 
                      rules in the
                      router.
Screened Subnet       subnet behind a screening router.degree to whichsubnet may
                      be accessed depends on the screening rules in router
Screening Router      A router configured to permit or deny traffic 
                      based on a set of
                      permission rules installed by the administrator.
Scroll Bar            The bar that appears at right side or bottom of a 
                      window that contains more information that can be 
                      displayed. The scroll bar is used to scroll an object or 
                      parts of 
                      a document into view when entire object or document does 
                      not fit in window. 
SDSUnet               San Diego State University Network. The backbone network 
                      that connects multiple buildings on SDSU campus. 
Search Engines        A type of software that creates indexes of databases or 
                      Internet sites based on titles of files, key words, or 
                      full text of files. 
Second Original       High-quality, contone reproduction of an image, intended 
                      to be identical to original. 
Secondary Color       Color obtained by mixing two primary colors. Although 
                      known as primary colorants, C,M, and Y are secondary 
                      colors of light. Red plus green produce yellow, for 
                      example. 
Serial Cable/Serial   Port 
                      A cable used to connect peripheral devices through a 
                      computer's serial port. Normally a 25-pin connector on 
                      each end, yet can be a 9-pin on one. A Serial Port can 
                      either be plugged into an expansion slot on motherboard 
                      of your computer or built into motherboard itself. Serial 
                      ports are used for such devices as printers, mice, 
                      and modems. 
Server                A computer that shares its resources, such as printers 
                      and files, with other computers on network. An example of 
                      this is a Novell NetWare Server which shares its 
                      disk space with a workstation that does not have a disk 
                      drive of its own. 
Service (NT service)  A process that performs a specific function in Windows NT 
                      and can be called by various other programs. Windows NT 
                      provides tools to monitor and administer 
                      services. 
                      Shadow 
                      The darkest area of an image. 
Session Stealing      See IP Splicing.


Shareware             Software that you can try before you buy. It's 
                      distributed through on-line services, BBSs, and user 
                      groups. You're allowed to try it out and give copies to 
                      others, but if 
                      you want to keep using it, you must pay registration 
                      fee. 
Shockwave             A set of programs that allow Macromedia Director 
                      animation files to be played over internet with a web 
                      browser. 
Site                  Organization or facility where a host is located. 
                      Site-license 
                      Through negotiations with a vendor, a renewable fee has 
                      been paid to allow a fixed number of copies of 
                      copyrighted software at one site. 
SLIP                  Serial Line Internet Protocol. A protocol used to run IP 
                      over serial lines, such as telephone circuits or RS-232 
                      cables, interconnecting two systems.
SMTP Server Hijacking (Unauthorized Relaying)
                      spammer take many thousands of copies of a message 
                      and send it to a huge list of email addresses. 
                      Because these lists are often so bad, 
                      and in order to increase speed of operation for spammer, 
                      many simply send all mail to SMTP server that
                      will take care of actually delivering mail.
                      Of course, all of bounces, spam complaints, hate mail,
                      and bad PR come for site was used as a relay. 
                      Bugs in Applications
                      web servers, mail servers, and other Internet service
                      software contain bugs that allow remote (Internet) users 
                      to do things
                      ranging from gain control of the machine to making that 
                      application crash
                      and just about everything in between. 
SMTP                  (Simple Mail Transport Protocol) - used to
                      send text-based information (e-mail)          
SNMP                  (Simple Network Management Protocol) - used 
                      to collect system information from a remote      
                      computer   
SMTP hijacking        SMTP is the most common
                      method of sending e-mail over the Internet. By 
                      gaining access to a list of e-mail addresses, a 
                      person can send unsolicited junk e-mail (spam) to  
                      thousands of users.        

SMTP                  Simple Mail Transfer Protocol. Internet standard protocol 
                      for transferring electronic mail messages from one 
                      computer to another. SMTP specifies how two mail 
                      systems interact and format of control messages they 
                      exchange to transfer mail. 
SOCKS                 generic proxy system can be compiled into client-side
                      application to make it work through afirewall. 
                      easy to use, but doesn't support authentication hooks or
                      protocol specific logging.
                      http://www.socks.nec.com/.

Socket                Logical address of a communications access point to a 
                      specific device or program on a host. 
Source routing        In most cases, the path a packet
                      travels over the Internet (or any other network) is
                      determined by the routers along that path. But the
                      source providing the packet can arbitrarily specify
                      the route that the packet should travel. Hackers
                      sometimes take advantage of this to make information
                      appear to come from a trusted source or even from
                      inside the network! Most firewall products disable
                      source routing by default.
Spam                  Typically harmless but always annoying, spam 
                      is the electronic equivalent of junk mail. Spam can 
                      be dangerous though. Quite often it contains links to 
                      Web sites. Be careful of clicking on these because  
                      you may accidentally accept a cookie that provides a 
                      backdoor to your computer.  
                      * Redirect bombs - Hackers can use ICMP to change 
                      (redirect) the path information takes by sending it  
                      to a different router. This is one of the ways that a  
                      denial of service attack is set up.            here!
SPAM                  Refers to practice of blindly posting commercial 
                      messages or advertisements to a large number of unrelated 
                      and uninterested newsgroups. 
Speckling             Isolated light pixels in predominantly dark image areas, 
                      sometimes caused by incorrect readings or noise in 
                      scanning device. 
Spectral Highlight    A bright reflection from a light source containing little 
                      or no detail. 
Spectrophotometer     An extremely accurate color measurement device using a 
                      diffraction grating to split light into its components 
                      wavelengths, which are then measured by numerous light 
                      sensors. 
Spreadsheet           A number-related document whereby calculations and 
                      formulas are applied to data organized in rows and 
                      columns of cells. 
SQL                   Structured Query Language, a syntax used by many database 
                      systems to retrieve and modify information. 
SSL work              through the firewall
                       SSL is a protocol that allows secure connections across 
                      the Internet.
                      Typically, SSL is used to protect HTTP traffic. However, 
                      other protocols
                      (such as telnet) can run atop SSL.
                      Enabling SSL through your firewall can be done the same 
                      way that you would
                      allow HTTP traffic, if it's HTTP that you're using SSL to 
                      secure, which is
                      usually true.  only difference is that instead of using 
                      something that
                      will simply relay HTTP, you'll need something that can 
                      tunnel SSL. This is a
                      feature present on most web object caches.
                      You can find out more about SSL from Netscape
Staircasing           See Aliasing. 
Start/Stop Bits       A start bit signals start of a unit of data in 
                      asynchronous communications. A stop bit signals stop of a 
                      unit of data. The unit can vary in length depending on 
                      protocol. 

Stateful inspection   A newer method that doesn't 
                      examine the contents of each packet but instead 
                      compares certain key parts of the packet to a 
                      database of trusted information. Information
                      traveling from inside the firewall to the outside is
                      monitored for specific defining characteristics, then 
                      incoming information is compared to these  
                      characteristics. If the comparison yields a  
                      reasonable match, the information is allowed through.
                      Otherwise it is discarded.
Subnet Address        An extension of Internet addressing system that allows a 
                      site to subdivide a single Internet address to cover 
                      multiple physical networks. This is done by dividing up 
                      host address part of an IP Address into a local network 
                      number and host address number. 
Substrate             The base material used to carry out or support an image, 
                      for example, paper or film. 
                      Subtractive Primaries 
                      Another term for primary colorants. 
Supersampling         The capture of more grey levels per color than is 
                      required for image manipulation or output. This 
                      additional data allows shadow details to be heightened, 
                      for example. 
Syntax Error          Occurs when a user (or programmer) has put words in an 
                      order that a program does not understand. 
                      T or Return to Quick Index 
T1                    An AT&T term for a digital carrier facility used to 
                      transmit a DS-1 formatted digital signal at 1.544 
                      megabits per second. 
T3                    A term for a digital carrier facility used to transmit 
Tags                  Formatting codes used in HTML documents. These tags 
                      indicate how parts of a document will appear when 
                      displayed by a Web client program. 
                      Taskbar 
                      An area that runs across bottom (usually) of Windows 95 
                      desktop. Running applications are represented as buttons 
                      on taskbar, current window is shown 
                      as a depressed button, all other applications are 
                      displayed as raised buttons.
TCP                   (Transport Control Protocol) - used to break
                      apart and rebuild information that travels over
                      the Internet 
TCP                   Transmission Control Protocol. This is a transport layer 
                      protocol that establishes a reliable, full duplex, data 
                      delivery service used by many TCP/IP application 
                      programs. 
                      The TCP software uses IP protocol to transmit 
                      information across Internet. 
TCP/IP                Transmission Control Protocol/Internet Protocol. A set of 
                      protocols, resulting from ARPA efforts, used by Internet 
                      to support services such as remote login 
                      (TELNET), file transfer (FTP) and mail (SMTP). 
Telnet                used to perform commands on a remote  
                      computer                                        
                      A company might set up only one or two machines to   
                      handle a specific protocol and ban that protocol on  
                      all other machines. 
TELNET                The Internet standard protocol for remote login (terminal 
                      connection) service. TELNET allows a user at one site to 
                      interact with a remote timesharing system at another 
                      site as if user's terminal were connected directly to 
                      remote computer. 
Terminal              Communication device that lets a user send information to 
                      a computer by typing on a keyboard, and prints responses 
                      from computer on paper or a screen. 
Terminal Mode         Many communications programs allow you to mimic a 
                      computer terminal, which is basically a keyboard and CRT 
                      display and/or a printer. A common terminal mode 
                      emulator is VT-100. 
Terminal Ready (TR)  This light is illuminated when your computer has turned 
                      on RS-232 (serial) interface. Sometimes this light will 
                      not come on until you have loaded your 
                      communications software into memory. 
Terminal Server       A small, specialized, networked computer that connects 
                      many terminals to a LAN through one network connection. A 
                      terminal server can also connect network users 
                      to asynchronous ports or a host. 
Thermal Wax Transfer  A printing process using small heating elements to melt 
                      dots of wax pigment on a carrier film, which are then 
                      transferred to paper or transparent film by contact. This 
                      differs from dye sublimation process in that individual 
                      dots do not fuse together, so thermal wax transfer 
                      appears to be of a lower resolution. 
Thread                In context of Windows NT, a thread is sometimes used to 
                      refer to an NT service. Threading also refers to a 
                      low-level system architecture concept used in some 
                      multitasking operating systems. 
Threshold             The point at which an action begins or changes. The 
                      threshold setting used in scanning line art determines 
                      which pixels are converted to black and which will become 
                      white. The threshold defined in USM process determines 
                      how large a tonal contrast must be before sharpening will 
                      be applied to it. 
TIFF                  Tag Image File Format. A graphic file format, TIFF files 
                      are also bit maps, but they can be any size, resolution, 
                      or color depth. It is most versatile, reliable, and 
                      widely 
                      supported bit-mapped format and is standard format for 
                      saving scanned images. However, format does have several 
                      variations which means that occasionally 
                      an application may have trouble opening a TIFF file 
                      created by another program. 
Title bar             The horizontal bar at top of a window. The title bar 
                      shows name of window. 
                      Tone Curves 
                      Also known as gamma curves. These are used to smoothly 
                      adjust overall tonal range of an image, or individual 
                      tonal ranges of each color channel. 
Toolbar               A collection of buttons that typically make more common 
                      tools for an application easily accessible. 
                      TSR 
                      Terminate and Stay Resident. 
                      U or Return to Quick Index 
Trojan Horse          A software entity that appears to do something normal 
                      but which,, contains a trapdoor or attack program.
Tunneling Router      A router or system capable of routing traffic 
                      by encrypting it and encapsulating it 
                      for transmission across an untrusted network, for
                      eventual de-encapsulation and decryption.
Social Engineering    An attack based on deceiving users or administrators 
                      at the target site. Social engineering attacks 
                      are typically carried out by
                      telephoning users or operators 
                      and pretending to be an authorized user,
                      to attempt to gain illicit access to systems.
UDP                   (User Datagram Protocol) - used for   
                      information that requires no response, such as   
                      streaming audio and video  
USM                   Unsharp masking. A process used to sharpen images. 
UUCP                  UNIX-to-UNIX Copy Program. This was initially a program 
                      run under UNIX operating system that allowed one UNIX 
                      system to send files to another UNIX 
                      system via dial-up phone lines. Today, term is more 
                      commonly used to describe large international network 
                      which uses UUCP protocol to pass news and 
                      electronic mail. 
Uncover               A database of book reviews, magazines, and articles, 
                      including FAX article delivery. It provides table of 
                      contents information for over 14,000 journals in all 
                      disciplines 
                      held by libraries in Colorado Academic and Research 
                      Libraries consortium and provides on-line access to ERIC, 
                      at education database. Coverage for most 
                      journals begins with 1989. 
UNICOS                A version of UNIX operating system adapted for CRAY 
                      computers. 
UNIX                  An operating system developed by Bell Laboratories that 
                      supports multiuser and multitasking operations. 
                      Upload 
                      Send a file to another computer using a modem. 
UPS                   Uninterruptible Power Supply. A unit that switches to 
                      battery power whenever power cuts out. 
URI                   Uniform Resource Identifier, a string of characters that 
                      represents location or address of a resource on Internet 
                      and how that resource should be accessed. A 
                      URI is a superset of Uniform Resource Locator. 
URL                   Uniform Resource Locator, a string of characters that 
                      represents location or address of a resource on Internet 
                      and how that resource should be accessed. World 
                      Wide Web pages are assigned a unique URL. Each hyperlink 
                      on a web page contains URL of page to be linked to. 
                      http://rohan.sdsu.edu/glossary.html is URL 
                      for this page. 
USENET                A network of newsgroups. There are thousands of 
                      newsgroups available through USENET. Each one covers a 
                      specific topic or subject area. 
User Id               The string of characters that identifies you. The name by 
                      which you are known to network. Also known as username. 
UUCP                  UNIX-to-UNIX Copy Program, a program that lets you copy 
                      files between UNIX systems. UUCP protocols are used to 
                      transfer news and Email messages through 
USENET.               V or Return to Quick Index 
Veronica              Very East Rodent-Oriented Net-wide Index to Computerized 
                      Archies. An index searcher of Gopher repositories. 
                      Searches are based on keyword criteria to help users 
                      find Gopher-based information without doing a 
                      menu-by-menu, site-by-site search. 
Videodisc             A 12-inch disk that's similar to an audio CD but holds 
                      visual images (such as high-quality movies) as well as 
                      music. Also called a laserdisc. 
Virtual Network       Perimeter
                      A network that appears to be 
                      a single protected network behind firewalls, 
                      which actually encompasses encrypted virtual links over
                      untrusted networks.
Virus                 A replicating code segment that attaches itself 
                      to a program or data file. Viruses might or might
                      not not contain attack programs or
                      trapdoors. Unfortunately, many have taken 
                      to calling any malicious code
                      a ``virus''. If you mean ``trojan horse'' 
                      or ``worm'', say ``trojan horse'' or ``worm''.
Viruses               Probably the most well-known threat is 
                      computer viruses. A virus is a small program that can 
                      copy itself to other computers. This way it can
                      spread quickly from one system to the next. Viruses 
                      range from harmless messages to erasing all of your
                      data.
Virus                 A program that replicates itself from one file or disk to 
                      another without your consent. They are spread through 
                      floppy disks, networks, and on-line services and can go 
                      undetected (unless you have an antiviral utility) until 
                      something goes wrong. Some viruses deliberately destroy 
                      data, and even those designed to be benign can cause 
                      crashes, slowdowns, and file corruption. 
VMS                   Digital Equipment Corporation proprietary operating 
                      system which runs on VAX series of machines. 
VOD                   Video On Demand. 
VRAM                  Video RAM. A type of memory dedicated to handling image 
                      displayed on a monitor. VRAM is built into many Macs, and 
                      it also comes on display cards. 
                      W or Return to Quick Index 
WAIS                  Wide Area Information Server. WAIS is best at searches 
                      for various sources of academic information that has been 
                      indexed based on content. Its indexes consist of 
                      every word in a document and each word carries same 
                      weight in a search. 
                      Wallpaper 
                      A graphical pattern displayed on desktop. 
Web browser           Also known as a Web client program, this software allows 
                      you to access and view HTML documents. Netscape, Mosaic, 
                      Lynx, WinWeb, and MacWeb are some 
                      examples of Web browsers. 
Web page              A document created with HTML that is part of a group of 
                      hypertext documents or resources available on World Wide 
                      Web. 
Web walking           Using a Web client program to move through documents 
                      available on World Wide Web. This casual browsing nature 
                      of navigating WWW has also been 
                      referred to as strolling, crawling and jumping. 
Webmaster             A person or group of people who maintain and administer a 
                      web server. Webmaster also refers to a standard Email 
                      address at most web hosts where comments and 
                      questions can be sent. 
White Point           A movable reference point that defines lightest area in 
                      an image, causing all other areas to be adjusted 
                      accordingly. 
WHOIS                 An Internet program which allows users to query databases 
                      of people and other Internet entities, such as domains, 
                      networks, and hosts. The information for people 
                      generally shows a person's company name, address, phone 
                      number and email address. 
                      Wide Area Network (WAN) 
                      Network spanning multiple geographic distances, usually 
                      connected by telephone lines, microwave, or satellite 
                      links. 
Wildcard              A character (usually * or ?) that can stand for one or 
                      more unknown characters during a search. 
Windows               Microsoft software that adds a Mac-like graphical user 
                      interface to IBM PCs and compatibles. 
Word Processing       Entering, editing and formatting text with use of 
                      spelling checkers, outlining, tables, footnotes, and 
                      tables of contents. 
Workstation           A networked personal computing device with more power 
                      than a standard IBM PC or Macintosh. Typically, a 
                      workstation has an operating system such as UNIX that 
                      is capable of running several tasks at same time. It has 
                      several megabytes of memory and a large high-resolution 
                      display. 
Worm                  standalone program that, when run, copies itself 
                      from one host to another, and then runs itself
                      on each newly infected host. The widely
                      reported ``Internet Virus'' of 1988 was not a virus 
                      at all, but actually a worm  

WWW                   World Wide Web or W3 is hypermedia document presentation 
                      system that can be accessed over Internet using software 
                      called a Web browser. 
WYSIWYG               What you see is what you get. The image you see on 
                      screen matches what will print on paper. Pronounced 
                      wizzy-wig. 
X.25                  A data communications interface specification developed 
                      to describe how data passes into and out of public data 
                      communications networks. The CCITT and ISO 
                      approved protocol suite defines protocol layers 1 through 
                      3. 
Zipped                Compressed version of a program or document.



ADSL                  Asymmetric Digital Subscriber Line. A high-speed Internet access technology
                      used for the Residential High Speed service, by Bell in parts of Ontario and
                      Quebec. A technology in which high-capacity transmission requirements, such
                      as compressed video signals are delivered through copper wire. In this case,
                      "asymmetric" refers to the transmission capacity towards the customer being
                      greater than that from the customer to the network.
Bandwidth             The amount of data that can be transmitted over a given time period.
Bit                   A contraction of the "binary digit". A bit is the smallest possible unit of
                      storage of computer information and can be one of two values. These values
                      are typically represented by 0 and 1, low and high, or on and off.
bps                   bits-per-second. A measure of data transmission, such as that handled by a
                      modem.
Broadband             A communications medium which is capable of carrying multiple messages at
                      the same time.
Dedicated Access      A direct connection between a terminal and a service, network or computer
                      dedicated to the specific use of a particular customer.
Dial access (roaming) Ability to access the Internet through a dial up connection.
Dial Up               The use of a rotary-dial or Touch-Tone? telephone to initiate a
                      station-to-station telephone call.
DSL                   Digital Subscriber Line. A term coined to refer to the family of DSL access
                      technologies, including ADSL, RADSL, VDSL, etc.
e-mail address        Electronic identification that enables users to send and receive electronic
                      mail.
Ethernet Card         The ethernet card provides a standardized way of connecting computers
                      together to create a network. Because DSL technology requirements far
                      exceeds the lower speed limits of standard serial/parallel connections now
                      uilt-in most PCs, a connection technology capable of interfacing at higher
                      speeds was required; ethernet technology, capable of sustaining traffic
                      volumes of up to 10MB, was chosen as the technology of choice.
Filter                A device that prevents noise interference and is installed between a
                      telephone and its wall jack.
Firewall              A system designed to prevent unauthorized access to or from a private
                      network. Firewalls can be implemented in both hardware and software, or a
                      combination of both. Firewalls are frequently used to prevent unauthorized
                      Internet users from accessing private networks connected to the Internet,
                      especially Intranets. All messages entering or leaving the Intranet pass
                      through the firewall, which examines each message and blocks those that do
                      not meet the specified security criteria. A firewall is considered a first
                      line of defense in protecting private information. For greater security,
                      data can be encrypted.
                      There are several types of firewall techniques:
Packet filter:        Looks at each packet entering or leaving the network and
                      accepts or rejects it based on user-defined rules. Packet filtering is
                      fairly effective and transparent to users, but it is difficult to configure.
                      In addition, it is susceptible to IP spoofing.
Application gateway:  Applies security mechanisms to specific
                      applications,such as FTP and Telnet servers. This is very effective, but can
                      impose performance degradation.
Circuit-level gateway Applies security mechanisms when a TCP?; or UDP
                      connection is established. Once the connection has been made, packets can
                      flow between the hosts without further checking.
Proxy server:         Intercepts all messages entering and leaving the network. The
                      proxy server effectively hides the true network addresses.
Gateway               This is a device that converts different protocols; a network
                      interconnectivity device that translates communications protocols.
In networking,        it is a combination of hardware and software that links two
                      different types of networks. Gateways between e-mail systems, for example,
                      allow users on different e-mail systems to exchange messages.
Gateway Address       A gateway address is the IP address of a network point that acts as an
                      entrance to another network. For example, in a corporate network, a proxy
                      server acts as a gateway between the internal network and the Internet.
Hub                   A common connection point for all devices connected to a star network. A
                      passive hub simply serves as a conduit for the data, enabling it to go from
                      one device to another. So called intelligent hubs include additional
                      features that enable them to act as a bridge, transferring data between
                      different types of networks. Some hubs are full-fledged computers that also
                      act as network servers.
HFC                   Hybrid Fibre-Coaxial. A high speed Internet access technology not yet
                      employed by the Sentex service.
Internet              A wide-area network that connects tens of millions of computers worldwide.
                      Originally implemented by the U.S. Defence Department, Internet is now
                      administered by an independent organization. Members include: government
                      agencies, educational institutions and large corporations.
Kbps                  Kilobits-per-second (thousands of bits-per-second). A measure of data
                      transmission, such as that handled by a modem.
Line                  A communications channel. Also called a circuit, trunk or facility. It often
                      refers to customer access to the public switched telephone network (e.g.,
                      residence line, individual business line).
Mbps                  Megabits-per-second (millions of bits-per-second). A measure of data
                      transmission, such as that handled by a modem.
Modem                 Device that modulates and demodulates data usually transmitted over a
                      regular telephone line
Network               A series of points interconnected by telecommunications channels.
Nortel Networks       1-Meg Modem
                      The 1-Meg Modem is a state-of-the-art all-digital device that communicates
                      using 10BaseT (ethernet) network protocols and provides an "always on"
                      connection to the network. The 1-Meg Modem is a "Plug and Play" Modem which
                      does not require the installation of a splitter.
Port                  The entrance or access point to a computer or multiplexer.
Proxy Server          A server that sits between a client application, such as a Web browser, and
                      a real server. It intercepts all requests to the real server to see if it
                      can fulfill the requests itself. If not, it forwards the request to the real
                      server. Proxy servers can also be used to filter requests. For example, a
                      company might use a proxy server to prevent its employees from accessing a
                      specific set of Web sites.
Router                A device that connects two LANs. Routers are similar to bridges, but provide
                      additional functionality, such as the ability to filter messages and forward
                      them to different places based on various criteria. The Internet uses
                      routers extensively to forward packets from one host to another.
Splitterless          "Splitterless ADSL" refers to the fact that this particular version of the
                      technology does not require an in-house installation by a qualified
                      technician of a special filter known as a POTS Splitter. Instead, the
                      splitterless ADSL service relies on the installation of small in-line
                      filters at each telephone set.
Streaming             A method of delivering information (usually sound and/or video) over the
                      Internet such that it can be played on a receiving computer at the same time
                      it is being delivered.
Subnet                A portion of a network that shares a common address component. On TCP/IP
                      networks, subnets are defined as all devices whose IP addresses have the
                      same prefix. For example, all devices with IP addresses that start with
                      100.100.100 would be part of the same subnet. Dividing a network into
                      subnets is useful for both security and performance reasons. IP networks are
                      divided using a subnet mask.
Telnet                A terminal emulation program for TCP/IP networks such as the Internet. The
                      Telnet program runs on your computer and connects your PC to a server on the
                      network. You can then enter commands through the Telnet program and they
                      will be executed as if you were entering them directly on the server
                      console. This enables you to control the server and communicate with other
                      servers on the network. To start a Telnet session, you must log into a
                      server by entering a valid username and password. Telnet is the most common
                      way to remotely control Web servers.
VADSL                 Very-High-Rate Asymmetric Digital Subscriber Line. A high-speed Internet
                      access technology.
Web Server            This is a computer that delivers (serves up) Web pages. Every Web server has
                      an IP address and possibly a domain name. For example, if you enter the URL
                      http://www1.sympatico.ca/Tools/ into your browser, a request is sent to the
                      server with the domain name: sympatico.ca. The server then fetches the page
                      named Tools and sends it to your browser.
                      Any computer can be turned into a Web server by installing server software
                      and connecting it to the Internet. There are many Web server software
                      applications, including public domain software from NCSA and commercial
                      packages from Microsoft, Netscape, and others.

                      Sentex Customer Support does not provide support for Web servers.


======================COMPUTER_WEB=============================== 

VRML                  Virtual Reality Modeling Language (pronounced'vermal')
                      format standard 3D multimedia and shared virtual worlds 
                      supports a "node" known as a MovieTexture. 
                      allows a video mapped onto surface of an object.  
                      MovieTexture node referenced by  texture field 
                      of an Appearance node.Each object has Appearance node.  
                      node includes a url field of a video file
                      to map onto surface of VRML object.  T
                      video file must be i MPEG-1 Systems AVI  not supported.
BinHex                Like UUENCODE,translates a binary file 
                      into printable 7-bit ASCII codes t
                      BinHex 4.0 files are identified by a first line:
                      (This file must be converted with BinHex 4.0)
                      followed by a blank line, 
                      followed by a colon, 
                      followed by the data.
PGP                   (Pretty Good Privacy) program. PGP
                      encrypt  printable 7-bit ASCII characters
                      which PGP's documentation
                      calls "ASCII-Armored Text".  
                      for Windows, Macintosh, and Unix.  
                      http://web.mit.edu/network/pgp
                      http://www.pgp.com/">Pretty Good Privacy, Inc.
uuencode              convert 8-bit graphics to 7-bit ASCII file. 
                      To uuencode and email a file:
                      % uuencode picture.img picture.img | Mail user@host.sit
                      Once the emailed data is received
                      % uudecode file
                      uuencode data format is the defacto standard of Usenet.
                      uuencoding will increase file size by  33%.
Split uuencode        graphics files split into 1000 line 60KB chunks 
                      (multi-part postings) f
                      If each chunk includes shell wrapper 
                      (string "[sh]"usually  in Subject line of postings), 
                      to decode a multi-part uuencoded posting 
                      part into a separate file, 
                      edit each file to remove the mailing headers
                      concatenate them all into a single file and uudecode
                      % vi picture.1 picture.2 picture.3
                      % cat picture.1 picture.2 picture.3 | uudecode
                      Posting a graphics file 
                      First, graphics file must be uuencoded. 
                      Second split into 60K chunks (1000 lines) for posting.
                      each chunk posted must be given  descr and  part number.
                      Under Unix use  uuencode, split, expr,inews commands 
                      % uuencode picture.img picture.img > picture.img.uue
                      % split -1000 picture.img.uue picture.img.uue.
                      % ls
                      Total 535
                      picture.img        picture.img.uue    picture.img.uue.1  
                      picture.img.uue.2  picture.img.uue.3
                      % sh
                      $ i=1
                      $ for j in picture.img.uue.*; do
                      > (echo "Subject: picture.img [$i/3]"
                      > echo "Newsgroups: news.test
                      > echo
                      > cat $j) | /usr/lib/news/inews
                      > i=`expr "$i" + 1`
                      > done
                      $ rm picture.img.*
                      $ exit
                      %
                      picture.img, uuencode it, to file  picture.img.uue. 
                      split into  picture.img.uue.1, picture.img.uue.2, 
                      and  picture.img.uue.3.  We then loop through each file 
                      and create a Subject: and Newsgroup: line 
                      for each of the file chunks and post them using inews.

copyrighted graphics  graphics file cannot be copyrighted 
                      For anything to be copyrighted it must be:
                      1) A work of authorship
                      2) Fixed in a tangible medium of expression
                      graphics file created using format
                      is not considered to be a work of authorship
                      format itself is considered instead to be an idea 
                      If  graphical data written to a graphics file 
                      also meets the above two criteria, 
                      then it is also protected by the copyright laws
                      will not wave your copyright protection 
                      by storing original information using a graphics format.
24 BIT RGB            (DE FACTO STANDARD)
                      All common graphics programs support 24-bit RGB. 
                      255 0   0    (a bright red pixel in 24 bit RGB)
                      0   255 0    (a bright green pixel in 24 bit RGB)
                      0   0   255  (a bright blue pixel in 24 bit RGB)
                      0   0   0    (a black pixel in 24 bit RGB)
                      255 255 255  (a white pixel in 24 bit RGB)
                      128 128 128  (a gray pixel in 24 bit RGB)
8 bit RGB             (uses a color palette)
                      look up table
32 bit RGB            (most significant byte is zero, 
                      8 bits red,8 bits green, and 8 bits blue)
16 bit RGB            ( 5 bits red, 6 bits for green, and 5 bits for blue)
15 bit RGB            (16 bits with most significant bit zero, 5 bits for red,
                      5 bits for green, and 5 bits for blue)
                      8 bit grayscale Y8
                      9 bit YUV9
                      12 bit BTYUV  4:1:1
                      12 bit YUY12   
                      16 bit YUY2   4:2:2
YUV Color Space       and Color Formats 
                      used in European PAL broadcast television
                      PAL introduced in Britain and Germany in 1967.  
                      United States and Japan use  NTSC standard.  
                      France and a few other use SECAM standard.
                      Y refers to luminance, weighted sum of red, green, blue
                      human most sensitive to  luminance
                      NTSC, PAL,SECAM transmit luminance (Y) signal and
                      two color difference or chrominance signals U and V).
                      If,RGB 
                      Y = 0.299 R + 0.587 G + 0.114 B
                      U = 0.493 (B - Y)
                      V = 0.877 (R - Y)
                      U similar to difference between blue and yellow
                      V similar to difference between red and green 
                      human processes color like a luminance channel, 
                      a blue - yellow channel, 
                      and a red - green channel. 
                      never percieve a hue simultaneously blue and yellow. 
COLOR TO GRAYSCALE    NTSC formula is:
                      luminosity = .299 red + .587 green + .114 blue

PDF                   Portable Document Format
                      viewable using Adobe's Acrobat Reader 2.0 program.
                      Software Developer's Kits for Unix, Macintosh, Microsoft
                      ftp://ftp.adobe.com/pub/adobe/Acrobat/SDK/
                      You can download a PDF plug-in for your Web browser from:
                      ftp://ftp.adobe.com/pub/adobe/Acrobat/
PICT                  Macintosh Picture
                      Inside Macintosh books in electronic form from:
                      http://dev.info.apple.com/insidemac.html
                      ftp://ftp.info.apple.com/Apple.Support.Area/\
                      Developer_Services/Technical_Documentation/\
                      Inside_Macintosh
                      ftp://ftp.info.euro.apple.com/Apple.Support.Area/\
                      Developer_Services/Technical_Documentation/\
                      Inside_Macintosh
DXF                   Autodesk Drawing eXchange Format
                      AutoCAD DXF (Drawing eXchange Format)
                      AutoCAD DXB (Drawing eXhange Binary) 
                      formats are the native vector file formats 
                      of Autodesk's AutoCAD CAD application.
                      DXF is  most widely supported vector formats 
                      support for 3D objects, curves, text, 
                      associative dimensioning, and is an easy format to parse.
                      Users are required to pay $4000US for license to AutoCAD 
                      in to obtain  specsfor this newest release of DXF file .
                      specification for DXF R12 been released 
                      ftp://avalon.vislab.navy.mil/pub/format_specs/\
                      dxf_r12.txt.Z
                      http://www.mediatel.lu/mmedia/render/h_dxf12.html
                      most current version, DXF R13, is available at:
                      ftp://ftp.synapse.net/private/c/cadsyst/misc/r13dxf.zip
                      excerpt of the DXF R10 specification may be found at:
                      http://www.mediatel.lu/mmedia/render/h_dxf10.html
                      Autodesk Inc.
                      Autodesk Developer Marketing
                      2320 Marinship Way
                      Sausalito, CA 94965
                      Voice: 415.491.8719
                      FTP:   ftp://ftp.autodesk.com/
                      WWW:   http://www.autodesk.com/
RenderMan             similar to PostScript, but for 3D primitives. 
                      specification  3.2  Pixar's web site:
                      http://www.pixar.com/products/rendermandocs/\
                      toolkit/Toolkit/
                      The '92, '98/'99, and '00 notes are must-haves.  
                      Several of these are
                      available downloadable in PDF form at
	                 http://www.renderman.org/RMR/Books/index.html#Sig


MIME                  Multipurpose Internet Mail Extension.  
                      to support multimedia attachments to Internet e-mail.   
                      consists of a type/subtype, for example
                      image/jpeg         for JPEG images.
                      following video subtypes were registered with IANA:
                      video/mpeg
                      video/quicktime
                      video/vnd.vivo
                      video/vnd.motorola.video
                      video/vnd.motorola.videop
                      video/avi
                      video/msvideo
                      video/x-msvideo
                      prefix "x-" unregistered, experimental MIME type.  
                      complete list of registered MIME types:
                      http://www.isi.edu/in-notes/iana/assignments/\
                      media-types/media-types
Apache httpd          free Apache httpd Web most popular Web server 
                      free implementation httpd daemon for Unix 
                      frequently run on Sun workstations used  Web servers.
                      Apache httpd looks in httpd.conf to configure Apache.  
                      One  directives is    AddType video/avi  .avi
                      see the Apache Web site:  http://www.apache.org/

domain names          standard top-level  and who controls them? 
                      .com (for commercial endeavors) 
                      .org (for non-profit organizations) 
                      .net (for network providers) 
                      .mil (for military organizations) 
                      .gov (for government organizations) 
                      .edu (for educational organizations) 
                      (.ca)Canada  Australia (.au), United Kingdom .uk), etc. 
                      IANA (Internet Assigned Numbers Association 
                      http://www.iana.org)
                      provides world-wide management of top level domain names.
ADN                   (Advanced Digital Network) -Usually 56Kbps leased-line.
ADSL                  (Asymmetric Digital Subscriber Line)method fordata over
                      regular phone lines ADSL circuit much faster than regular
                      phone connection, wires coming into subscriber's premises
                      same (copper) wires used for regular phone service. ADSL
                      circuitconfigured to connect two specific locationssimilar
                      to a leased line.
                      commonlyconfiguration of ADSL would allow subscriber to
                      receive data (download) up to 1.544 megabits (not
                      megabytes) per second, send (upload)  128
                      kilobits per second. Thus "Asymmetric" part ofacronym.
                      Another configuration  symmetrical: 384
                      Kilobits per second both dire. theory ADSL allows download
                      speeds  to 9 megabits per secand upload speeds  640
                      kilobits per second.
                      ADSL  often discussed asalternative to ISDN,
                      in cases where the connection always to same place.
Anonymous FTP         See: FTP
Applet                small Java program embedded in n HTML page. Applets
                      they are not allowed
                      to access certain resources on local computer, 
                      such as files and serial devices (modems, 
                      other computers across a network. The current
                      rule an applet can only make aInternet connection to
                      computer from which the applet was sent.
Archie                (software) for finding files stored on anonymous FTP site
                      need to know the exact file name or a substring of it.
ARPANet               (Advanced Research Projects Agency Network) 
                      precursor Internet. Developed in late 60's  early 70's 
                      by  US Department of Defense as experiment 
                      in wide-area-networking that
                      would survive a nuclear war.                 
ASCII                 (American Standard Code for Information Interchange)
                      world-wide standard forcode numbers used by computers to
                      represent all the upper and lower-case Latin letters
                      There are 128 standard ASCII codes each of which can
                      be represented by a 7 digit binary number:
Backbone              high-speed line or series of connections 
                      that forms a major pathway
                      within a network.  backbone in a small network
                      be much smaller than non-backbone lines in a large
                      network.
Bandwidth             How much stuff can send through connection. measured 
                      bits-per-second. full page  English text is 16,000 bits.
                      fast modem  about 15,000 bits in one second. Full-motion
                      full-screen video  10,000,000 bits-per-second,
                      depending on compression.
Baud                  common usage the baud rate of a modem 
                      how many bits it can send or receive per second.  
                      Technically, baud is the number of times per
                      second that the carrier signal shifts value - 
                      for example a 1200 bit-per-second modem 
                      actually runs at 300 baud, but it moves 4 bits per
                      baud (4 x 300 = 1200 bits per second).
BBS                   (Bulletin Board System computerized meeting announcement
                      system allows people discussions, upload and download
                      files, make announcements withou people being connected 
                      computer at same time. many thousands (millions?) of
                      BBS's around  world, mostvery small, a single IBM
                      clone PC with 1 or 2 phone lines. Some large and line
                      between BBS and system like CompuServe gets crossed 
                      but it is not clearly drawn.
Binhex                (BINary HEXadecimal)  method converting non-text files
                      into ASCII.  e-mail can only handle ASCII.
Bit                   (Binary DigIT) -either a 1 or a zero.                  
BITNET                (Because It's Time NETwork
                      (or Because It's There NETwork)) -- A
                      network of educational sites separate from Internet,e-mail
                      freely exchanged between BITNET and Internet. 
Bps                   (Bits-Per-Second)  28.8 modem  move 28,800 bits per sec
Browser               Client program (software) used to look at 
                      Internet resources.
BTW                   (By The Way) -- A shorthand appended to comment
Byte                  set of Bits represent  single character. Usually 8
                      Bits in a Byte,                 
CertificateAuthority  issuer of Security Certificates used in SSL connections.
CGI                   (Common Gateway Interface) -rules how a Web
                      Server communicates with  software on  same machine,
                      how software (the "CGI program") talks to 
                      web server. Anysoftware can be  CGI program if  handles
                      input and output according to the CGI standard.
                      CGI program  a small program that takes data from web
                      server and does something, like putting  content ofform
                      into e-mail message, or turning data into database query.
cgi-bin               common directory on a web server in which CGI
                      programs are stored.
                      "bin" part of "cgi-bin"  shorthand version "binary", 
                      once upon a time, most programs refered to as "binaries".
Client                software program tused to contact and obtain data from 
                      Server software program on another computer,across great
                      distance. Client program designed to work with one or more
                      kinds of Server programs,each Server requires a specific
                      kind of Client. Web Browser isspecific kind of Client.
co-location           refer to having a server that belongs to one person
                      or group physically located Internet-connected network 
                      belongs to another person or group. Usually because 
                      server owner wants their machine a high-speed Internet
                      connection and/or do not want security risks of having
                      server on thier own network.
Cookie                "Cookie" on the Internet refers to a piece
                      information sent by Web Server to Web Browser thatBrowser
                      software expected to save and send back to Server whenever
                      browser makes additional requests from Server.
                      Depending on the type of Cookie used, and the Browser's
                      Cookies might contain information as login or registration
                      info, online "shopping cart" infor , user prefer, etc.
                      WhenServer request from Browser that includes a Cookie,
                      Server is able use information stored in Cookie. For
                      example,Server might customize what sent back to user, or
                      keep alog of particular user's requests.
                      Cookies set to expire after predetermined amount of time
                      saved in memory until Browser software is closed
                      down,they may be saved to disk if their "expire time"
                      has not been reached.
                      Cookies do not read your hard drive 
                      but they can be used to gather more informat about user 
Cyberpunk             originally a cultural sub-genre of science fiction taking
                      place in not-so-distant, over-industrialized society. 
                      term grew out ofwork of William Gibson and Bruce Sterling 
                      evolved into cultural label encompassingdifferent kinds of
                      human, machine, and punk attitudes.clothing and lifestyle
                      choices as well.
Cyberspace            originated by author William Gibson novel Neuromancer
                      word Cyberspace  used to describe the whole range of
                      information resources available through computer networks.
Digerati              digital version of literati reference to a vague cloud of
                      people seen to be knowledgeable, hip, in-the-know in
                      regards to thdigital revolution.
Domain Name           unique name identifies Internet site. Domain Names always
                      part on the left is the
                      most specific, part on the right is the most general. 
                      machine may have more than one Domain Name but a given
Domain Name           points to only one machine. 
                      Usually, all machines on given Network will have  same
                      right-hand portion of their Domain Names (matisse.net in
                      the examples above). possible for a Domain Name to exist 
                      not be connected to an actual machine.often done so 
                      group or business have Internet e-mail address without 
                      real Internet site.  some real Internet
                      machine must handle the mail on behalf of the listed 
E-mail                (Electronic Mail) -- Messages, usually text, 
Ethernet              very common method of networking computers in a LAN. 
                      handle about 10,000,000 bits-per-second and 
FAQ                   (Frequently Asked Questions) -- list and answer
                      most common questions on particular subject. 
FDDI                  (Fiber Distributed Data Interface) -standard transmitting 
                      on optical fiber cables around 100,000,000 bits-per-second
                      (10 times as fast as Ethernet,  twice as fast as T-3).
Finger                Internet software tool for locating people on other sites.
                      also  used to give access to non-personal
                      information, most common is to see if a person has an
                      account at a particular Internet site.
Fire Wall             combination of hardware and software separates  LAN 
                      into two or more parts for security purposes.
Flame                 Originally, meant to carry forth in passionate manner in 
                      spirit of honorable debate. most often involved use of
                      flowery language and flaming well was art form. recently
                      come to refer to any derogatory comment no matter how
                      witless or crude.
Flame War             online discussion degenerates into personal attacks
                      against debators, rather than discussion ofpositions. A
                      heated exchange.
FTP                   (File Transfer Protocol) - moving files
                      between two Internet sites. special way to login to 
                      Internet site for retrieving and/or sending files.
                      repositories of material obtained using FTP, logging in
                      using account name anonymous, sites called anonymous
                      ftp servers.
Gateway               a hardware or software set-up that translates
                      between two dissimilar protocols,  sloppier meaning is to
                      describe any mechanism providing access to another system
GIF                   (Graphic Interchange Format) -- format for image files,
Gigabyte              1000 or 1024 Megabytes, depending on who is measuring.
Gopher                widely successful method of making menus of material 
                      available over the Internet. Gopher is Client and Server
                      requires that user have Gopher Client program.
                      largely supplanted by Hypertext,
hit                   "hit" means a single request from a web browser 
                      for a single item from a web server;
Home Page             Originally, web page your browser is set to
                      use  starts up.  common meaning refers to main web
                      page for business, organization, person orthe main page 
                      of collection of web pages, e.g. "
Host                  computer on network a repository for services available
                      to other computers on network. common to have one host
                      machine provide several services,  WWW and USENET.
HTML                  (HyperText Markup Language) -- coding language used
                      Hypertext documents on  World Wide Web. HTML a lot
                      like old-fashioned typesetting code surround block text
                      with codes that indicate how it should appear, 
                      HTML files are meant to be viewed using a World
                      Wide Web Client Program, such as Netscape or Mosaic.
HTTP                  (HyperText Transfer Protocol)  protocol moving hypertext
                      files across Internet. HTTP client program one end,
                      and HTTP server program on  other end. HTTP is 
                      protocol used in  World Wide Web (WWW).
Hypertext             any text  contains links to other documents - words or
                      phrases in document that can be chosen and which cause
                      another document to be retrieved and displayed.
IMHO                  (In My Humble Opinion) shorthand appended 
                      IMHO indicateswriter is aware that they are
                      expressing a debatable view,
Internet              (Upper case I)  vast collection inter-connected networks 
                      use the TCP/IP protocols and  evolved from ARPANET of 
                      60's  early 70's. Internet now (July 1995) connects 
                      60,000 independent networks into  vast global internet.
internet              (Lower case i) connect 2 or more networks together, 
                      have an internet - as in inter-national or inter-state.
Intranet              private network inside a company or organization 
                      is only for internal use. in private networks,
IP Number             (Internet Protocol Number) called a dotted quad. unique
                      number consisting of 4 parts separated by dots, e.g.
                      165.113.245.2
                      Every machine  on  Internet has  unique IP number - if 
                      does not have an IP number, not really on  Internet.
                      Most machines also have one or more Domain Names  easier 
                      people to remember.
IRC                   (Internet Relay Chat)  huge multi-user live chat
                      facility.  major IRC servers around  world
                      which are linked to each other. Anyone create channel 
                      anything in a given channel is seen by all others in
                      channel. Private channels created for multi-person
                      conference calls.
ISDN                  (Integrated Services Digital Network)  way to move 
                      data overregular phone lines. ISDN  rapidly becoming
                      available to much of the USA and  is priced very
                      comparably to standard analog phone circuits. speeds of
                      roughly 128,000 bits-per-second over regular phone lines.
                      most people limited to 56,000 or 64,000 bits-per-second.
ISP                   (Internet Service Provider) - institution provides access 
                      Internet in some form, usually for money.
Java                  Java network-oriented programming language by Sun
                      specifically designed for writing programs that
                      downloaded to your computer through the Internet 
                      immediately run without fear of viruses or other harm 
                      Using small Java programs (called "Applets"), Web pages
                      include functions such as animations, calculators,
                      you can write a Java program to do almost anything a
                      regular  program can do,  then include Java program in
                      a Web page.
JDK                   (Java Development Kit) software development from Sun
                      that implements the basic set of tools needed to write,
                      test and debug Java applications and applets
JPEG                  (Joint Photographic Experts Group) -- JPEG 
                      format for image files.is preferred to  GIF format
                      for photographic images as opposed to line art 
Kilobyte              thousand bytes. Actually, usually 1024 (2^10) bytes.
LAN                   (Local Area Network) -- network limited to  immediate
                      area, usually  same building or floor of a building.
Leased-lin            phone line that is rented for exclusive 24-hour, 7
                      -days-a-week use from your location to another . highest
                      speed data connections require a leased line.
Listserv®             most common kind maillist, "Listserv" registered trademark
                      L-Soft international, Inc.  originated on BITNET but 
                      now common on the Internet.
Login                 account name used to gain access
                      act of entering into a computer system, 
Maillist              (or Mailing List) A (usually automated) system  people to
                      send e-mail to one address,their message  copied and sent
                      to all of  other subscribers to  maillist.  people
                      many different kinds of e-mail access can participate 
                      discussions together.
Megabyte              A million bytes. Actually, technically, 1024 kilobytes.
MIME                  (Multipurpose Internet Mail Extensions) standard attaching
                      non-text files to standard Internet mail messages.     
                      graphics, spreadsheets, formatted word-processor ,
                      sound files, etc.
                      email program  MIME Compliant if  can both send and
                      receive files using the MIME standard.
                      non-text files sent using  MIME standard converted
                      (encoded) into text - resulting text is not really
                      readable. MIME standard  specifying both the
                      type of file being sent (e.g. a Quicktime[tm] video file),
                      method  used to turn it back into  original form.
                      MIME standard universally used by Web Servers
Mirror                "to mirror" ismaintain an exact copy of
                      something. common use of the term on  Internet
                      refers to "mirror sites" web sites, or FTP sites that
                      maintain  copies  material originated at another location,
                      to provide more widespread access to  resource.
                      Another common use term "mirror" an arrangement where
                      information more than one hard disk simultaneously, so
                      if one disk fails, computer keeps on working
Modem                 (MOdulator, DEModulator) --  connect to  computer
                      and phone line, computer to talk to other
                      computers through the phone system.
MOO                   (Mud, Object Oriented) -- One  kinds of multi-user
                      role-playing environments, only text-based.
Mosaic                first WWW browser that was available 
MUD                   (Multi-User Dungeon or Dimension) usually text-based 
                      multi-user simulation environment. for fun and flirting, 
                      or serious software development, or education purposes 
                      significant feature of most MUDs is that
                      users can create things stay after they leave which other
                      users can interact in their absence, allowing world to be
                      built gradually and collectively.
MUSE                  (Multi-User Simulated Environment) -- kind of MUD - 
                      little or no violence.
Netiquette            The etiquette on the Internet.
Netizen               referring to a citizen of the Internet,
                      or someone who uses networked resources. connotes civic
                      responsibility and participation.
Netscape              WWW Browser and the name of a company.Netscape (tm)
                      originally Mosaic program developed at National Center
                      for Supercomputing Applications (NCSA).
                      main author Mark Andreessen, was hired away from the
                      NCSA by Jim Clark, founded a company called Mosaic
                      Communications changed  name to Netscape Communications
                      Corporation.
Network               connect 2 or more computers together so that they can
                      share resources, Connect 2 or more
                      networks together and you have an internet.
Newsgroup             The name for discussion groups on USENET.
NIC                   (Networked Information Center)  any office that handles
                      information for network. most famous  Internet is
                      InterNIC, where new domain names are registered.
                      NIC also refers to Network Interface Card which
                      plugs into a computer and
                      adapts  interface to appropriate standard. ISA, PCI, and
                      PCMCIA cards are all examples of NICs.
NNTP                  (Network News Transport Protocol) protocol used by client 
                      server to carry USENET postings backforth over TCP/IP
                      network. If using  more common software such as
                      Netscape, Nuntius, Internet Explorer, etc. in newsgroups
                      you are benefiting from an NNTP connection.
Node                  Any single computer connected to a network.
Packet Switching      method used to move data around on  Internet. In packet
                      switching, data coming out of machine is broken up into
                      chunks, each chunk has address where came from and where 
                      going. enables chunks data from many different sources to
                      co-mingle on same lines, and sorted and directed different
                      routes by special machines along way. many people can use
                      same lines at the same time.
Password              code used to gain access to a locked system. 
Plug-in               small piece of software that adds features to larger
                      piece of software. plug-ins for the Netscape®
                      browser and web server. Adobe Photoshop® uses plug-ins.
                      small piece of software is loaded
                      into memory by larger program, adding new feature, users
                      need only install few plug-ins they need, out of larger
                      pool of possibilities. Plug-ins  created by people other
                      than publishers of software the plug-in works w
POP                   (Point of Presence, also Post Office Protocol) -- 
                      Point of Presence and Post Office Protocol. A Point of
                      Presence means a city or location where network can be
                      connected to, often with dial up phone lines.
                      Post Office Protocol refers  e-mail software as Eudora 
                      When you obtain a SLIP, PPP, or shell account you
                      almost always get a POP account with it, this POP account
                      you tell your e-mail software to use to get your mail.
Port                  serial port on a personal
                      computer is where a modem would be connected.
                      Internet port often refers to number that  part of URL,
                      appearing after colon (:) right after  domain name.service
                      on Internet server listens on particular port number on
                      server. Most have standard port numbers, e.g. Web servers
                      normally listen port 80. Services also listen non-standard
                      ports,which port number must be specified in a URL when
                      accessing the server, so you might see a URL of the form:
                      gopher://peg.cwis.uci.edu:7000/
                      gopher server running on non-standard port (standard
                      gopher port is 70).
                      port also refers to translating  software 
                      from one computer system to another, e.g. to translate a
                      Windows program so that is will run on a Macintosh.
Portal                marketing term to described Web site that
                      intended to be  first place people see when using  Web. 
                      "Portal site" has catalog of web sites, search engine, 
                      Portal site offer email e to entice people to
                      use  site main "point of entry" (hence "portal") to
Posting               single message entered into network communications system.
PPP                   (Point to Point Protocol) a protocol that allows
                      computer to use  telephone line and modem to make TCP/IP
                      connections andand truly on the Internet.
PSTN                  (Public Switched Telephone Network) regular old-fashioned
                      telephone system.
RFC                   Request For Comments) name of  result and process for
                      creating standard on Internet. New standards proposed 
                      published  line, as Request For Comments. Internet 
                      Task Force is consensus-building body  discussion,
                      eventually a new standard is established, but reference
                      number/name for standard retains  acronym RFC,  official
                      standard for e-mail is RFC 822.
Router                special-purpose computer  software package) handles 
                      connection between 2 or more networks spend all  time
                      looking at  destination addresses of packets passing 
                      them and deciding which route to send them on.
Security Certificate  chunk information (often text file)  used by
                      SSL protocol to establish a secure connection.
                      Security Certificates contain infor who it belongs to, who
                      it was issued by, unique serial number  other unique
                      identification, valid dates, encrypted "fingerprint"  
                      used to verify  contents of  certificate.
                      for  SSL connection  created both sides must have a
                      valid Security Certificate.
SSL                   computer, or software provides a specific kind of
                      service to client software running on other computers. 
                      The term can
server                refer to a particular piece of software, 
                      single server machine could have several servers running
SLIP                  (Serial Line Internet Protocol)  standard using regular
                      telephone line (a serial line) and modem to computer 
                      real Internet site. SLIPgradually being replaced by PPP.
SMDS                  (Switched Multimegabit Data Service) standard for very
                      high-speed data transfer.
SMTP                  (Simple Mail Transfer Protocol)main protocolsend
                      electronic mail on the Internet.
                      Internet email is sent and received by clients and servers
                      using SMTP, 
SNMP                  (Simple Network Management Protocol)  set standards for
                      communication with devices connected to a TCP/IP network.
                      "PDU's" -             Protocol Data Units.
                      Devices SNMP compatible contain SNMP "agent" software to
                      receive, send, and act upon SNMP messages.
Spam (or Spamming)    inappropriate attempt use  mailing list,  other
                      networked communications facility as a broadcast medium
                      (which it is not)sending same message to large number of
                      people who didn't ask for it. term probably comes 
                      Monty Python the word spam repeated over and over.
                      generally perceived as a generic
                      content-free waste of resources. 
SQL                   (Structured Query Language) programming language for
                      sending queries to databases.
SSL                   (Secure Sockets Layer) -protocol designed by Netscape
                      to enable encrypted, authenticated communications across
                      the Internet.
                      URL's that begin with "https" indicate that
                      In SSL connection each side connection must have Security
                      Certificate, which each side's software sends to other. 
                      Each side then encrypts what it sends 
                      using information from both its own and the
                      other side's Certificate, ensuring only intended recipient
                      de-crypt it,that  other side  sure  data came from 
                      place it claims to have come from, and message  not been
                      tampered with.
Sysop                 (System Operator) responsible for operations of
                      computer system or network .System Administrator decides
                      how often backups and maintenance and  System
                      Operator performs those tasks.
T-1                   leased-line connection data at 1,544,000
                      bits-per-second. At maxtheoretical capacity,  T-1 line 
                      megabyte less  10 seconds. still not fast enough for
                      full-screen, full-motion video, you need  least 10,000,000
                      bits-per-second. T-1 fastest speed commonly used
                      networks to the Internet.
T-3                   leased-line connection capable data at 44,736,000
                      bits-per-second.  more  enough to do full-screen,
                      full-motion video.
TCP/IP                (Transmission Control Protocol/Internet Protocol) -
                      protocols defines the Internet. Originally  for 
                      UNIX operating system, TCP/IP software now  for every
                      computer operating system.  on the Internet, your
                      computer must have TCP/IP software.
Telnet                command and program to login from one Internet site to
                      another. The telnet command/program gets you to the login:
Terabyte              1000 gigabytes.
Terminal              device  to send commands to a computer somewhere else.
Terminal Server       special  computer has places to plug in many modems on
                      one side, onnection to LAN or host machine on other side.
                      terminal server  answering the calls and
                      passes the connections on to the appropriate node. 
                      servers can provide PPP or SLIP services
UDP                   (User Datagram Protocol)  protocols  data transfer 
                      part of  TCP/IP  protocols. UDP  a "stateless" protocol
                      makes no provision for acknowledgement of packetsreceived.
UNIX                  computer operating system
URL                   (Uniform Resource Locator) standard give  address of
                      resource on  Internet
USENET                world-wide system discussion groups,  comments passed 
                      hundreds of thousands of machines. Not all USENET machines
                      Internet, maybe half. completely decentralized, over
                      10,000 discussion areas, called newsgroups.
UUENCODE              (Unix to Unix Encoding)  converting files from Binary to
                      ASCII (text) so sent across the Internet via e-mail.
Veronica              (Very Easy Rodent Oriented Net-wide Index 
                      to Computerized Archives) --
                      DevelopedUniversity of Nevada, Veronicaconstantly updated
                      database of names  every menu item on thousands of gopher
                      servers. Veronica database searched from most major gopher
                      menus.
VPN                   (Virtual Private Network)  network in which some
                      parts are connected using  public Internet, but  data sent
                      across  Internet is encrypted, entire network "virtually"
                      private.
WAIS                  (Wide Area Information Servers)commercial software  
                      allows  indexing of huge quantities of information, making
                      indices searchable across networks such as Internet. A
                      prominent feature of WAIS is search results are ranked
                      (scored) according to how relevant  hits are,  subsequent
                      searches can find more stuff like last batch and refine 
                      search process.
WAN                   (Wide Area Network) internet or network covers an area
                      larger than  single building or campus.
WWW                   (World Wide Web)  used (incorrectly) referring to
                      " Internet", two major meanings -the
                      whole constellation of resources accessed using Gopher,
                      FTP, HTTP, telnet, USENET, WAIS and other tools. , 
                      universe of hypertext servers (HTTP servers)  servers that
                      allow text, graphics, sound files, etc.  mixed together

=======================COMPUTER_SLIP_PPP===============================

=======================IP-Addressing-and-Routing-for-SLIP-and-PPP========

IP addresses          comes from the Network Information Center (NIC), 
                      arbitrates the whole Internet. 
SLIP and PPP          are interchangeable in this document.
IP address            for PPP-client determined by the IP network 
A Few" Clients        (Proxy ARP)
                      use an IP address on the network of the server.
                      client sets up  default route through  PPP interface,
                      server does a "proxy arp" for the client.
                      least demands on routing.
On the client,        the rest of the world is accessed via the PPP interface
                      server acts in proxy client for packets goingother way. 
                      client has it's Ethernet interface disabled,
                      one of  following techniques:
                      1. `chkconfig network off` and rebooting
                      2. Leave   IP address associated with `hostname` 
                      (the same as the contents of /etc/sys_id) 
                      as  default 192.0.2.1. 
                      explicitely specify localhost= in /etc/ppp.conf 
                      (or the equivalent for SLIP), 
                      if using static IP address assignment.
                      3.  dit  file /etc/config/ifconfig-1.options 
                      to contain the    value "down".
following a packet    during the operation `ping sgigate.sgi.com`.
                      * IP first looks up sgigate.sgi.com in /etc/hosts, 
                        IP  address is 204.94.209.1.
                      * IP address not samelocal host, IP looks in 
                        routing table for interfacefor 204.94.209.0 network.
                        one  matches is "default" and points to  PPP interface.
                      * packet gets shipped server, IP routing points to 
                        correct router.
                      * packet eventually to sgigate.sgi.com, where the
                        echo-server (ping server) sends a return packet.
                      * Routing gets packet  to  router on PPP-server's network.
                      * then uses Address Resolution Protocol (ARP) 
                        to determine Ethernet address   PPP-client's IP address.
                      * The PPP-server then responds "me! me!"
                      * PPP-server  send  packet over  PPP link, back toclient.
Proxy server          on the gateway host
                      A Proxy is a program that is run on the gateway host
                      that acts as  intermediary for  other hosts on network.
                      The Internet hosts talks to  proxy, 
                      and since it runs on the gateway, 
                      the ISP only has to know about the one host. 
SOCKS                 is a common proxy servers,  is free. 
                      The Netscape browser knows about SOCKS proxies, 
                      SOCKS code comes with SOCKS-ified versions 
                      of ftp and telnet. 
TIS Firewall Kit      also provides proxy capabilities, 
mechanisms            require that all your hosts be able to get nameservice.
If gateway is proxy,  then your gateway must run a nameserver 
                      or at least nameserver forwarding code.
Nameservice           for local machine is 
                      handled by the /etc/resolv.conf configuration file 
PPP                   (Point to Point Protocol) way of extending 
                      TCP/IP network over point-to-point links 
                      (like phone lines). 
hostnames             are designed to be (usually) easier to remember, 
                      and they will (usually) remain the same 
                      even when the IP address changes. 
mapping               the hostname into an IP address. 
                      procedure is called hostname resolution.
                      * NIS: Network Information Service 
                      (used to be known as YP == Yellow Pages).
                      * DNS: Domain Name Service 
                      (sometimes known by the name of one implimentation: bind)
                      * "local":  mapping  kept locally in  /etc/hosts file.
                      This is  order that Irix name resolution defaults 
TCP/IP                applications use 4 layers:
                      application protocol  as mail
                      protocol such as TCP 
                      IP, getting datagrams to destination
                      protocols to manage a specific physical medium, such as
                      Ethernet or a point to point line.
TCP/IP                based on the "catenet model". 
model assumes         large number independent networks connected  by gateways. 
                      to access another system  "Internet address". 
                      like 128.6.4.194.  actually a 32-bit number.
                      4 decimal , each representing 8 bits of address. 
octet                 used by Internet documentation for  8-bit
byte                  not used,  some computers  byte other than 8 bits 
128.6                 a network number assigned bycentral authority 
                      to Rutgers University. 
                      Rutgers uses  next octet  which Ethernets involved. 
                      128.6.4  Ethernet  Computer Science Department. 
                      last octet  up to 254 systems on each Ethernet. 
0 and 255             are not allowed, 
specify  name         network software looks up Internet address.
TCP/IP                built on "connectionless" technology. 
                      Information is transfered as "datagrams". 
datagram              collection of data sent through network individually. 
                      a unit of data, which protocols deal with. 
packet                physical thing, appearing on an Ethernet or some wire. 
                      most cases a packet simply contains a datagram, 
                      so there is very little difference. 
TCP                   ("transmission control protocol") 
                      responsible breaking up  message into datagrams, 
                      reassembling them at  other end, 
                      resending anything that gets lost, 
                      putting things back in the right order. 
IP                    (the "internet protocol") 
                      responsible for routing individual datagrams. 
TCP                   has to know which connection this datagram part of. 
                      referred to as "demultiplexing." 
                      information  contained series of "headers". 
header                few extra octets  the beginning of datagram 
                      by some protocol in order to keep track of it. 
TCP  header           at the front of each datagram. 
                      actually contains at least 20 octets,
                      most important ones source and destination "port number" 
                      and a "sequence number". 
port numbers          are used to keep track of different conversations. 
                      When  sending, this becomes "source" port number, 
TCP                   has assigned a port number of its own for conversation. 
                      TCP has to know port number by other end as well. 
                      finds out when  connection starts, 
                      It puts this in the "destination" port field. 
Each datagram         has a sequence number gets  datagrams in right order, 
                      and that it hasn't missed any. 
                      TCP doesn't number the datagrams, but the octets.
                      if there are 500 octets of data in each datagram, 
                      the first datagram might be numbered 0,
                      the second 500, the next 1000, the next 1500, etc. 
Checksum.             is computed by adding up all octets in datagram 
                      The result is put in the header. 
TCP                   at the other end computes the checksum again. 
                      If they disagree, it is thrown away.
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |          Source Port          |   Destination Port  |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |                        Sequence Number              |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |                    Acknowledgment Number            |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |  Data |           |U|A|P|R|S|F|                     |
                      | Offset| Reserved  |R|C|S|S|Y|I|        Window       |
                      |       |           |G|K|H|T|N|N|                     |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |           Checksum            |     Urgent Pointer  |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |   your data ... next 500 octets                     |
                      |   ......                                            |
If  abbreviate  TCP   header as "T", 
                      the whole file now looks like this:
                      T....   T....   T....   T....   T....   T....   T....
acknowledgement       recipient has to send back an "acknowledgement". 
                      datagram whose "Acknowledgement number" field filled in 
                      sending packet with acknowledgement 1500 
                      indicates  received all data up to octet number 1500. 
                      If  doesn't get acknowledgement within time, 
                      it sends the data again. 
window                used to control how much data in transit at any time. 
                      not practical to wait for each datagram be acknowledged
                      before sending the next one.
                      That would slow things down too much. 
                      other hand, you can't just keep sending, 
                      fast computer might overrun a slow one to
                      each end indicates how much new data it is currently
                      prepared to absorb 
                      by putting the number of octets in its "Window" field. 
                      As computer receives data,space left in window decreases. 
                      When it goes to zero, the sender has to stop.
                      As receiver processes the data, increases its window, 
                      indicating ts ready to accept more data.
Urgent                field allows one end to tell the other to skip
                      ahead in its processing to a particular octet. 
                      often useful forhandling asynchronous events,
                      for example when you type a control character
                      or other command that interrupts output. 
IP level              TCP sends each datagrams to IP. 
                      Of course it has to tell IP the
                      Internet address of the computer at the other end.
                      IP's job is simply to find a route for datagram 
                      and get it to the other end.
                      it adds its own header. 
IP header             source and destination Internet address
                      (32-bit addresses, like 128.6.4.194), 
                      the protocol number, 
                      and another checksum. 
source Internet       address is simply address of your machine. 
destination Internet  address is the address of the other machine. 
protocol number       tells IP at other end to send datagram to TCP. 
                      Although most IP traffic uses TCP, 
                      are other protocols that can use IP
                      you have tell IP which protocol to send the datagram to.
checksum              allows IP at the other end to verify that the header
                      wasn't damaged in transit.
                      TCP and IP have separate checksums. 
                      IP needs to verify the header didn't get damaged 
                      or it could send a message to the wrong place. 
IP tacked on header   here's what the message looks like:
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |Version|  IHL  |Type of Service|      Total Length     |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |         Identification        |Flags|  Fragment Offse |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |  Time to Live |    Protocol   |     Header Checksum   |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |                       Source Address                  |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |                    Destination Address                |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      |  TCP header, then your data ......                    |
                      |                                                       |
If IP header an "I"   your file now looks like this:
                      IT....   IT....   IT....   IT....   IT....   IT....
flags                 and fragment offset are used to keep track of pieces 
                      when a datagram has to be split up. 
                      when datagrams through network which they are too big.
The time to live      is a number that is decremented 
                      whenever the datagram passes through a system. 
                      When it goes to zero, the datagram is discarded. 
                      done in case a loop develops in the system somehow. 
                      should be impossible, but well-designed networks 
                      are built to cope with "impossible" conditions.
At this point,        it's possible that no more headers are needed. 
Ethernet level        However most of our networks these days use Ethernet.
                      So now we have to describe Ethernet's headers. 
Ethernet              has its own addresses.
                      people who designed Ethernet 
                      wanted to make sure that no two machines
                      would end up with the same Ethernet address. 
                      they didn't want user to worry about assigning addresses. 
                      each Ethernet controller comes 
                      with address builtin from the factory. 
                      Into make sure they would never have to reuse addresses, 
                      Ethernet  allocated 48 bits for  Ethernet address. 
                      People who make Ethernet equipment 
                      have to register with a central authority, 
                      to make sure numbers  don't overlap . 
Ethernet              a "broadcast medium".  like an old party line telephone. 
                      When you send a packet out on the Ethernet, 
                      every machine on the network sees the packet. 
Ethernet header       Every Ethernet packet has a 14-octet header 
                      that includes source and destination Ethernet address, 
                      and a type code. 
                      Each machine supposed to pay attention only  packets 
                      with  own Ethernet address in destination field. 
                      no connection between the Ethernet address 
                      and the Internet address. 
Each machine          has to have a table of what Ethernet address 
                      corresponds to what Internet address. 
type code             to allow for several different protocol families
                      to be used on the same network. 
                      can use TCP/IP, DECnet, Xerox NS, etc. at the same time. 
                      Each will put a different value in the type field. 
checksum.             Ethernet controller computes  checksum of entire packet. 
                      other endrecomputes the checksum, 
                      throws the packet away if answer disagrees 
                      checksum is put on the end of the packet, not in header.
final result          is that your message looks like this:
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++
                      |       Ethernet destination address (first 32 bits)     |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      | Ethernet dest last 16 bits|Ethernet source first16 bit)|
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+
                      |       Ethernet source address (last 32 bits)           |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+
                      |        Type code              |
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-
                      |  IP header, then TCP header, then your data         
                      |                                                        
                      ...
                      |                                                        
                      |   end of your data                                    
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-
                      |                       Ethernet Checksum               
                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--
Ethernet header "E",  and Ethernet checksum with "C", file now looks like 
                      EIT....C   EIT....C   EIT....C   EIT....C   EIT....C
                      When these packets are received by the other end, 
                      of course all the headers are removed. 
Ethernet interface    removes the Ethernet header and the checksum. 
                      It looks attype code. type code is one assigned IP,
                      Ethernet device driver passes  datagram to IP. 
IP                    removes the IP header.looks atIP protocol field. 
                      Since protocol type is TCP, passes  datagram up TCP. 
TCP                   now looks at the sequence number.
                      uses sequence numbers to combine into original file.
Well-known sockets    and applications layer
application           protocols". 
                      application protocols run "on top" of TCP/IP. 
                      they give the message to TCP. 
                      TCP makes sure it gets delivered to the other end. 
                      TCP and IP take care of all the networking details,
apps protocols        can treat a network connection as terminal or phone line.
                      to send a file to 128.6.4.7. 
                      have to connect to FTP server at  other end.
                      When connect 128.6.4.7,have to specify FTP server. 
                      done by having "well-known sockets" for each server. 
well-known sockets    specific port numbers assigned to programs 
                      that sit waiting for requests.
                      port number 21 for the FTP server. 
                      two different programs involved. 
                      You run ftp on your side. 
                      program designed toaccept commands from your terminal 
                      and pass them on to the other end.
                      you talk to on the other machine is the FTP server. 
                      designed to accept commands from the network connection, 
                      rather than an interactive terminal. 
official port         numbers for each program are given in "Assigned Numbers".
                      Note connection  described by set of 4 numbers:
                      Internet address at each end, 
                      TCP port number at each end.
                      Every datagram has all four of those numbers in it. 
                      (The Internet addresses are in the IP header, 
                      and the TCP port numbers are in the TCP header.) 
                      no two connections can have same set of numbers.
                      for two different users sending files same  machine. 
                      could result in connections with the following parameters:
                                     Internet addresses         TCP ports
                      connection 1  128.6.4.194, 128.6.4.7      1234, 21
                      connection 2  128.6.4.194, 128.6.4.7      1235, 21
                      port number for program users  enough  difference. 
at least one end      of the connection asks the network software 
                      to assign it a port number 
                      Normally, it's the user's end, 
                      since the server has to use a well-known number.
mail protocol         program opens connection to other mail server 
                      Your program gives your machine's name, 
                      sender of message, and who to send to  
                      sends command saying it starting  message. 
                      other end starts accepting message. 
                      end of message, special mark sent (dot in 1st column).
                      both ends resume command mode.
File transfers        two different connections. 
                      It starts out just like mail. 
                      user's program sends commands like "log me as user",
                      "here is my password", "send me  file". 
                      once  command to send data  sent,
                      second connection opened for data itself. 
                      designers of  file transfer protocol 
                      wanted to continue issuing commands
                      while the transfer is going on. 
Remote terminal       For remote logins, just one connection
                      normally sends data. 
                      When it is necessary to send a command 
                      a special character is used to indicate command.
"net ASCII".          ASCII characters,  end of line denoted 
                      by a carriage return followed by a line feed. 
"standard terminal"   For remote login,   a half-duplex terminal with
                      echoing happening on the local machine. 
SMTP                  "simple mail transfer protocol
                      computer called TOPAZ.RUTGERS.EDU
wants to send         the following message.
                      Date: Sat, 27 Jun 87 13:26:31 EDT
                      From: hedrick@topaz.rutgers.edu
                      To: levy@red.rutgers.edu
                      Subject: meeting
                      Let's get together Monday at 1pm.
format of message     Internet standard (RFC 822). 
                      standard specifies message must net ASCII 
                      ASCII, with carriage return/linefeed  
describes             general structure, 
                      as a group of header lines, 
                      then a blank line, 
                      and then the body of the message. 
Finally,              describes the syntax of header lines 
                      Generally consist of keyword then value.
first query           find which machines handle mail for RED.RUTGERS.EDU. 
                      server replies RED.RUTGERS.EDU handles its own mail. 
program then asks     for address of RED.RUTGERS.EDU, which is 128.6.4.2. 
                      Then mail program opens a TCP connection 
                      to port 25 on 128.6.4.2. 
Port 25               is the well-known socket used for receiving mail. 
                      Once this connection is established, 
                      the mail program starts sending commands. 
typical conversation  TOPAZ initiated the connection:
                      RED    220 RED.RUTGERS.EDU SMTP Service 
                      at 29 Jun 87 05:17:18 EDT
                      TOPAZ  HELO topaz.rutgers.edu
                      RED    250 RED.RUTGERS.EDU - Hello, TOPAZ.RUTGERS.EDU
                      TOPAZ  MAIL From:
                      RED    250 MAIL accepted
                      TOPAZ  RCPT To:
                      RED    250 Recipient accepted
                      TOPAZ  DATA
                      RED    354 Start mail input; end with .
                      TOPAZ  Date: Sat, 27 Jun 87 13:26:31 EDT
                      TOPAZ  From: hedrick@topaz.rutgers.edu
                      TOPAZ  To: levy@red.rutgers.edu
                      TOPAZ  Subject: meeting
                      TOPAZ
                      TOPAZ  Let's get together Monday at 1pm.
                      TOPAZ  .
                      RED    250 OK
                      TOPAZ  QUIT
                      RED    221 RED.RUTGERS.EDU 
                      Service closing transmission channel
commands              all use normal text.typical of Internet  standards.    
                      easy  to  watch  what  is  going  on for problems. 
                      mail program keeps a log of each conversation. 
                      something goes wrong, log  file mailed  to postmaster.  
                      he can see what was going on.  
                      also allows a human to interact  directly  
                      with  the mail  server,  for  testing. 
responses             all begin with numbers. typical of Internet  protocols.
                      allowable  responses  defined  in  protocol.  
                      numbers allow  user program to respond unambiguously.  
                      rest  response  is  text, use by human 
                      has no effect on  operation  of programs.  
                      (However there is one point at which the protocol uses
                      part of the text of the response.)   
                      Every  session  must  begin  with  HELO, 
                      which gives  name system initiated  connection.  
                      Then the sender and  recipients are specified.  
                      (more than one RCPT command, if several recipients.)  
                      Finally the data itself is sent.  
                      text of message  terminated by  a period.
                      (such line in  message, the period is doubled.) 
                      After  accepted, send another message, or terminate
just  look            at the first digit.  
                      2  indicate  success.    
                      3  further action is needed,
                      4  "temporary" error, such as  a  disk  filling.
                      5  permanent error, as a  non-existent  recipient.    
Protocols             other than TCP: UDP and ICMP
name lookup.          will generally specify the system by name, 
                      rather than Internet address.
                      a few systems have database used to translate 
                      query  very short. it seems silly to use TCP. 
common alternative    UDP ("user datagram protocol"). 
                      where don't need to put datagrams together. 
                      It fits into  system  like TCP. 
                      There is a UDP header. on  front of your data,
                      UDP sends  data to IP, which adds the IP header, 
                      putting UDP's protocol number in the protocol field 
                      all that UDP provides is port numbers, 
Another alternative   protocol ICMP ("Internet control message protocol").
                      ICMP is used for error messages, 
                      and  messages intended for the TCP/IPsoftware itself, 
                      For example,an ICMP message  "host unreachable".
                      It doesn't even have port numbers in  header.
                      ICMP messages are interpreted by the network software
                      no port numbers  needed to say where ICMP message to go.
domain system         network software needs 32-bitInternet address 
name servers          keep track of host names and Internet addresses. 
                      (just one kind of information stored in domain system.) 
a set                 of interlocking servers are used, 
                      rather than a single central one.
                      impractical to notify a central authority 
                      whenever they installed or moved a computer. 
naming authority      delegated to individual institutions. 
                      name servers form a tree, 
                      corresponding to institutional structure.
                      names themselves follow a similar structure.
A typical example     BORAX.LCS.MIT.EDU. 
                      computer at Laboratory for Computer Science (LCS) at MIT. 
                      First, ask a central server (called the root) 
                      where the EDU server is.
                      EDU is a server,keeps track of educational institutions. 
The root server       give names and Internet addresses 
                      of several servers for EDU.
                      would then ask EDU where server for MIT is.
                      it give names and Internet addresses 
                      of several servers for MIT. 
                      Then ask MIT where server for LCS is, 
                      finally  ask one of  LCS servers about BORAX. 
final result          Internet address for BORAX.LCS.MIT.EDU. 
Each levels           is referred to as a "domain".
                      entire name, BORAX.LCS.MIT.EDU, called a "domain name".
                      software generally remembers answers it got before.
                      Each pieces of information has "time to live" a few days. 
Each domain name      is node in a database. 
                      node can have records Internet address, computer type, 
                      a list of services provided by a computer. 
Routing               IP getting datagrams to  destination
                      task of finding how to get to destination is "routing". 
                      simply finds the Ethernet address of the destination
                      system, and puts the datagram out on the Ethernet.) 
                      on a different network. problem is handled by gateways.
gateway               system that connects networks. 
                      normal computers that have multi network interface. 
                      Unix machine  connected to networks 128.6.4 and 128.6.3. 
                      is gateway between two networks. 
Routing               based entirely upon network number destination
                      system expects to find an entry for network 
                      that destination is on.  datagram is sent 
                      to gateway listed in that entry. 
                      This table can get quite big. 
                      Often, only one gateway out of a network. 
                      connect a local Ethernet to campus-wide backbone network. 
                      
                      don't need separate entry for every network in the world. 
                      We simply define that gateway as a "default". 
                      
                      When no specific route found for a datagram, 
                      the datagram is sent to the default gateway. 
                      
                      A default gateway can even be used when
                      there are several gateways on a network. 
                      There are provisions for gateways
                      to send a message saying "I'm not the best gateway -- 
                      use this one instead."
                      (The message is sent via ICMP. See RFC 792.) 
                      Most network software is
                      designed to use these messages to add entries 
                      to their routing tables.
                      Suppose network 128.6.4 has two gateways, 
                      128.6.4.59 and 128.6.4.1.
                      128.6.4.59 leads to several other internal 
                      Rutgers networks. 128.6.4.1 leads
                      indirectly to the NSFnet. Suppose we set 
                      128.6.4.59 as a default gateway,
                      and have no other routing table entries. 
                      Now what happens when we need to
                      send a datagram to MIT? MIT is network 18. 
                      Since we have no entry for
                      network 18, the datagram will be sent to 
                      the default, 128.6.4.59. As it
                      happens, this gateway is the wrong one. 
                      So it will forward the datagram to
                      128.6.4.1. But it will also send back an 
                      error saying in effect: "to get to
                      network 18, use 128.6.4.1". Our software 
                      will then add an entry to the
                      routing table. Any future datagrams to 
                      MIT will then go directly to
                      128.6.4.1. (The error message is sent 
                      using the ICMP protocol. The message
                      type is called "ICMP redirect.")
computers             should not keep track of entire network. 
                      Instead, start with default gateways, 
                      let the gateways tell them the routes, .
                      However this doesn't say how the gateways 
                      should find out about the routes.
                      The gateways can't depend upon this strategy. 
                      They have to have fairly
                      complete routing tables. F
routing protocol      technique for gateways to find each other,
Internet addresses    32-bit numbers, normally
                      written as 4 octets (in decimal), e.g. 128.6.4.7. 
actually 3            different types of address. 
                      address indicate both network and host within  network.
                      It was felt some very big networks 
                      might need 24 bits to represent all of their hosts. 
                      his would seem to lead to 48 bit addresses. 
                      designers wanted 32 bit addresses. adopted a kludge. 
                      assumption  most of networks small. 
                      set up three different ranges of address. 
"class A" addresses   Addresses 1 to 126 use first octet for network number.  
                      other three octets  available for  host number. 
                      Thus 24 bits are available for hosts  for large networks.
                      there can only be 126 of these very big networks. 
                      Arpanet is one, a few large commercial networks.
                      few normal organizations get one of these . 
"class B" addresses   normal large organizations,  
                      use the first two octets for the network number. 
                      network numbers are 128.1 through 191.254. 
                      (We avoid 0 and 255, for reasons that we see below.
                      also avoid addresses beginning with 127,
                      last two octets are available for host
                      addesses, giving 16 bits of host address. 
                      64516 computers, for most organizations. 
                      (possible to get another class B address, ifrun out.) 
class C addresses     use three octets, in the range 192.1.1 to 223.254.254. 
                      allow only 254 hosts on each network, 
                      but there can be lots of these networks. 
Addresses above 223   reserved for future use, 
class D and E         (which are currently not defined).
"subnets".            Many large organizations find it 
                      convenient to divide their network number
                      into "subnets". 
                      Rutgers class B address, 128.6. 
                      use  third octet of  address to indicate which Ethernet 
                      a host is on.  no significance outside of Rutgers.
                      computers outside Rutgers would not have
                      different routes for 128.6.4 or 128.6.5. 
                      inside Rutgers, 128.6.4 and 128.6.5 separate networks. 
0 and 255             have special meanings. 
0 is reserved         for machines that don't know their address. 
                      0.0.0.23  a machine that knew it was host number 23, 
                      but didn't know on what network.
255 is used           for "broadcast". 
                      broadcast message want every system on network to see. 
                      used  where you don't know who to talk to. 
                      Sometimes don't know address of  nearest name server.
                      It is not possible to send broadcasts on  Arpanet, 
                      or on point to point lines. is possible on Ethernet.
                      If use  Ethernet address with all bits  ones, 
                      every machine on  Ethernet  to look at  datagram.
official              broadcast address for network 128.6.4 
                      is now 128.6.4.255, 
                      255.255.255.255 refers to all hosts on local network. 
                      often simpler to use 255.255.255.255 
                      instead of finding out  network number for local network 
                      and forming a broadcast address
                      such as 128.6.4.255. 
certain older         implementations may use 0 instead of 255 
                      to form the broadcast address. 
                      Such implementations would use 128.6.4.0 
                      instead 128.6.4.255 as address on network 128.6.4. 
                      not understand about subnets. 
                      assume broadcast address of 128.6.255.255 or 128.6.0.0. 
normal hosts          should never be given addresses  containing 0 or 255. 
                      Addresses should never begin with 0, 127, 
                      or any number above 223. 
Martians              Addresses violating these rules are sometimes 
                      referred to as "Martians", 
                      because of rumors that the Central
                      University of Mars is using network 225.
Datagram              fragmentation and reassembly
                      network designers do not agree how big packets 
                      Ethernet packets can be 1500 octets long. 
                      Arpanet packets have a maximum of around 1000 octets. 
                      Some very fast networks have much larger packet sizes.
TCP "negotiate"       about datagram size. 
                      When a TCP connection first opens, both ends can send 
                      maximum datagram size they can handle. 
                      smaller of these numbers is used
                      they will both be prepared to handle 1500-octet datagrams
                      However the connection will at some point 
                      end up going over the Arpanet. 
                      It can't handle packets of that size. For this reason, 
fragmentation         are provisions to split datagrams up into pieces. 
                      (This is referred to as "fragmentation".) 
IP header             contains fields indicating  a datagram has been split, a
                      and enough information  put back together. 
If a gateway          connects an Ethernet to the Arpanet, 
                      take 1500-octet Ethernet packets 
                      and split them into pieces that will fit on Arpanet.
                      every host implementation of TCP/IP 
                      must be prepared to accept pieces 
                      and put them back together. referred to as "reassembly".
                      common for implementations to use 576-byte datagrams
                      whenever they can't verify that the entire path 
                      576 bytes is a "safe" size, every  must support.
Ethernet              encapsulation: ARP
ARP                   ("address resolution protocol").
                      how to figure out what Ethernet address to use
                      when you want to talk to a given Internet address. 
                      separate protocol for this
                      (Note by the way that ARP is not an IP protocol. 
ARP datagrams         do not have IP headers.) Suppose you are on system 
                      first verify on same network, so can talk  via Ethernet. 
                      Then it will look up in  ARP table, 
                      to see if it already knows the Ethernet address. 
                      If so, will stick on Ethernet header, and send  packet.
suppose system        is not in the ARP table. 
                      uses the ARP protocol to send an ARP request. 
ARP request           says "I need the Ethernet address for 128.6.4.7". 
                      Every system listens to ARP requests. 
                      When a system sees ARP request for itself, 
                      it is required to respond. 
                      So 128.6.4.7 will see the request, 
                      will respond with ARP reply saying in effect
                      "128.6.4.7 is 8:0:20:1:56:34". 
                      (Recall that Ethernet addresses are 48 bits.
                      This is 6 octets. 
Ethernet addresses    are conventionally shown in hex, 
                      using the punctuation shown.
                      Your system save this information in its ARP table, 
                      so future packets will go directly. 
                      Most systems treat the ARP table as a cache, 
                      clear if not been used in certain period of time.
ARP requests          must be sent as "broadcasts". T
                      no way ARP request can be sent directly to right system. 
                      whole reason for sending an ARP request 
                      is that you don't know the Ethernet address. 
Ethernet address      of all ones is used, i.e.   ff:ff:ff:ff:ff:ff. 
                      By convention, every machine on the Ethernet is required
                      to pay attention to packets with this as an address.
                      every system sees every ARP requests. 
Switching Regulator   output stage, switched repetitively on and off,  
                      energy storage components (capacitors and inductors) 
                      to generate an output voltage.  
                      Regulation through  adjustment of switch timing based 
                      fixed-frequency regulators, adjusted through modulation 
                      pulse width of switch voltage known as PWM control.  
                      gated-oscillator or burst-mode regulators, 
                      switch pulse width and frequency is kept constant, b
                      output switch is gated on or off by feedback control.  
buck (step-down)      switching regulator more efficiently than linear regulator
LDO (Low Drop-Out)    Regulator? linear regulator. 
                      very low drop-out voltage, typically around 200mV 
Switched-Capacitor    Converter?
                      typical switched-capacitor converter 
                      contains four large MOS switches, switched in 
                      sequence to typically invert, double, 
                      or halve input supply voltage. Energy transfer 
                      and storage are provided by external capacitors. 
first switching       input voltage  applied across (C1).  
                      second part  charge from C1  transferred to C2.  
                      traditional switched-capacitor converter  an inverter,
                      C2 has its positive side referred to ground, 
                      its negative side delivers  negative output voltage. 
                      After a number of cycles, 
                      voltage across C2 will be pumped up to  inpu  voltage. 
                      charge transfer efficiency 
                      depends on  switching frequency, 
                      on-resistance of the switches, 
                      capacitor value and series resistance.
Error Flag            an open-collector output  provides a signal 
                      when  output voltage  drops more than 5% (typically)  
                      start up,  Error Flag is low 
                      until  output voltage reaches 95% nominal output 
                      some cases delay added to Error Flag's power-OKtransition 
                      delay set by  external capacitor, 
                      can be used as  Power-On-Reset function 
                      to reset a microprocessor on power-up. 
If there is           a bar shown over the term "Error",
                      a low output voltage condition 
                      causes the open  collector output to be high 
                      (flag transistor OFF).  
                      When the output voltage is within 5% of nominal, 
                      this Flag output is low. 
On/Off or Shutdown?   feature allows regulator to  turned on or off 
                      while power is applied to  its input.  
                      While in  Off or Shutdown mode,  
                      regulator's supply current drops to  low level
                      as the output stage is disabled 
                      but  internal bias circuitry  still operational.  
                      When turned On again, 
                      regulator regains regulation of  output voltage 
                      much more quickly
If a bar              shown over the "On" part of On/Off or over "Shutdown",
                      regulator  turned on with alogic high. 
                      Otherwise, a logic low enables the regulator. 
What is Sync          (synchronization) or Frequency Adjust?
                      switching regulators and switched-capacitor converters
                      an internal oscillator set frequency 
                      Some converters allow  frequency to  changed 
                      either by  "Frequency Adjust"
                      or  synchronizing  to external source ("Sync"). 
                      increasing  switching frequency, 
                      smaller components used 
                      may reduce  efficiency of the converter, 
                      If there several converters on a board, 
                      good practice to synchronize 
                      minimizes any "beat  frequency" 
                      important with higher-power
                      converters, e.g. 5W and up.
A Cookie?             small piece of information  sent by web server to
                      stored on  web browser, 
                      later be read back from  browser 
                      next time unique visitor returns to  web server. 
                      for browser remember specific information 
                      like location of their last visit, time spent, 
                      or user preferences (like style sheets).
cookie                is a text file that is saved in  browser's directory 
                      and is stored in RAM while the browser is running. 
command line          in  HTML code of a document 
                      tells browser to set cookie of certain name or value
example               of a script used to set a cookie.
                      Set-Cookie: name = VALUE;
                      expires = DATE;
                      path = PATH;




                                       MAIN


acoustic coupler Ñ A device consisting of two cups
  mounted on a base, into which one inserts a
  telephone handset. The acoustic coupler is
  connected to a modem, which sends its signals
  directly through the mouthpiece of the phone,
  and receives signals through the earpiece.
  Useful for hacking on-the-run, such as from
  telephone booths and public fax machines.

amplifier Ñ A device for increasing the amplitude
  of a signal without altering its quality.

analog signal Ñ An output that changes in
  proportion with changes in the input producing
  it.

anonymous FTP Ñ The ability to transfer a file
  from a remote computer connected to Internet
  without having an account on  the remote
  computer. (Though the remote system actually
  does know who is logged in.) One enters
  ÒanonymousÓ for username, and usually oneÕs
  email address for the password. The program-
  that performs the file transfer is called FTP.

sary


application program Ñ Any software that is not
   part of the operating system. A word processor
   is an application program. These are where you
   hide Trojan horses. Sometimes called ÒappÓ for
   short.

archive Ñ Several files grouped together and
   generally compressed into a single ifie. This is
   done to facilitate uploading and downloading
   those perhaps unwieldly files to other sites.
   Archive also refers to a computer or drive
   which acts as a repository for files, especially a
   drive which can be accessed via FTP.

asynchronous Ñ Multiple programs or processes
   overlapping each other in execution and pos-
   sible memory. An asynchronous attack on a
   system involves one program attempting to
   change the parameters that the other has
   checked as valid but has not yet used. For ex-
   ample, it is illegal for just any old user to invoke
   the ÒsuÓ command to make himself a superuser
   Ñ doing so gets an error message. But if the
   contents of memory that hold the Òreject request
   for superuser statusÓ are changed to Òaccept

  request for superuser statusÓ by another proc-
  ess, then the original ÒsuÓ command will exe-
  cute.

avatar Ñ Alternative name for the root or
  superuser on a (usually UNIX) system. In
  Hindu mythology, an avatar is the incarnation
  of a god.

backbone site Ñ Key USENET and email site-
  which processes a large amount of third-party
  traffic. That is, it receives and sends news and
  messages to other sites.

back door Ñ Synonym for trapdoor.

baud Ñ Pulses per second (pps), with the as-
  sumption that each pulse is identical in
  amplitude. One baud is considered to equal one
  bit per second. Thus, when all pulses have the
  same amplitude, baud refers to bits transmitted
  per second.

BIOS Ñ Basic Input/Output System. Consists of a
  piece of code used to govern the elementary
  system-level functions of a computer.

bit Ñ The smallest unit of data that a computer can
  understand.

BITNET Ñ A network of normally mini or main-
  frame computers.  BLTNET connects many
  universities and colleges together. It provides e-
  mail and file transfer capabilities. It does not
  have the ability to do remote login (telnet
  sessions).

BBS Ñ Bulletin Board System. A computer set up
  to receive modem calls. Users dial in, then have
  access to various features including e-mail,
  message exchanges, games, and text files.

boffin Ñ Term used circa World War II to refer
  with admiration to hacker-like folk who wanted
  to understand how the world worked, and used
  their knowledge to invent accouterments for the
  world. Now we refer to ourselves as hackers.

browsing Ñ To ferret out data that has been left
  behind in computer memory or on storage
  media after the termination of a critical pro-
  gram or process.

bps Ñ Short for Òbits per second.Ó

buffer overflow Ñ A buffer is a (usually tempo-
  rary) holding area for data. Overflow happens
  when excess data is fed to a buffer, without
  giving it time to digest previous intake. Two
  reasons for buffer overflow: The buffer may not
  be sufficiently large to contain all the data that
  is needed before processing of that data can
  begin, or there may be a mismatch in the rates
  of data production to data consumption. A
  person might try and hack his way out of a
  program by inducing buffer overflow.

byte Ñ8 bits. Informally, a byte is a small amount
  of memory, just enough to hold a single letter,
  digit, or other character.

C Ñ A popular programming language that, along
  with its cousin C++, any hacker should have at
  least a passing familiarity with. UNIX is written
  inC.

chat Ñ To talk to another user online. In BBS cir-
  cles, chat would imply talking with the sysop
  on a single-user system.

CCTV Ñ Closed Circuit TeleVision. Security
  cameras set up in office buildings and else-
  where are monitored on CCTV.

CD-ROM Ñ Compact Disc Read Only Memo
  Some computers use compact discs the w
  other computers use floppy disks. Often 1
  databases are distributed on compact discs.

CIC) Ñ Chief Information Officer.

console Ñ On a mainframe, the station which
  system operator uses to control the compu
  or whichever tty the system was booted
  Also, cty and ctty.

console PBX Ñ Desktop switching service.

covert channel Ñ A way to secretly communicate
  information out of a private domain of a sys-
  tem, such as an account.

cracker Ñ A hacker who does not respect the
  computers he or she hacks.

ctyÑConsole tty. (Also ctty).

daemon Ñ Short for Disk And Execution MONitor.
  A program that is not explicitly started either
  by the user or the program the user is using, but
  rather one that lies dormant, watching for a set
  of conditions to hold true, then it will start
  itself. Pronounced Òday-mmÓ or Òdee-mm.Ó
  Also, demon.

demodulation Ñ The process of removing an audio
  signal from its high frequency carrier. When a
  modem demodulates those funny beeps coming
  over the phone line, it is shedding the high
  pitched, waste portion, and retrieving the
  usable information.

demon Ñ Similar to a daemon, except this program
  is invoked by a user or another program.

DES Ñ Data Encryption Standard. A standard
  encryption technique for scrambling data.

detector Ñ An electrical circuit used to remove the
  modulation from a carrier signal. Also a device
  which makes use of such a circuit.

DOS Ñ Disk Operating System. Term used to refer
  to operating systems in general, or to the
  operating system of the Apple II series. Also
  used loosely to mean either MS-DOS or PC-
  DOS.

dual-tone multifrequency dialing Ñ A dialing
  method using a pair of tones, one high and one
  low. Touch Tone phones use this method.

dumb terminal Ñ A device that allows input to a
  computer (such as through a keyboard) and
  output from the computer (through a video
  screen) Ñ and nothing else. Contrast with
  smart terminal.

duplex Ñ Simultaneous communication in two
  directions. Two telephones connected together
  make a duplex system, but if one of the tele-
  phones has its mouthpiece broken off, it be-
  comes a simplex system.

EDP Ñ Electronic Data Processing.

e-mail Ñ Short for electronic mail. Sometimes seen
  as email. The ability to have a private message
  exchange between two or more users on a BBS,
  network, or other computer system. Also refers
  to the message itself.

firewall machine Ñ A machine equipped with
  various security features, used as a gateway to
  protect the main computers. Users must get
  through the safety features of the firewall in
  order to access the important computer or
  network beyond.

FOIM Ñ Field Office Information Management
  System, computer used by the FBI to automate
  the routine administrative and record keeping
  functions of their field and resident offices.

FTP Ñ File Transfer Protocol. A set of protocols by
  which files can be transferred from one
  computer to another. FTP is also the name of a
  program that uses the file transfer protocols to
  move files back and forth between computers.

FTS Ñ Federal Telecommunications System. A
  direct-dialing phone system used by agencies of
  the federal government for voice, scrambled
  voice, high-speed  data, fax, and teletype
  communications.

group accounts Ñ A single computer directory or
  account protected by passwords, where the
  passwords are distributed to a number of users.
  For instance, all secretaries at an office might
  use the same account.

hacker Ñ Time for a pop quiz! Read this book, then
  use your own judgment to compose a definition
  for the word.

handle Ñ An assumed name; an alias. Often used
  on BBSs.

handshaking Ñ The process or activity by which
  two separate pieces of hardware coordinate
  their signals so that they can work together,
  usually to send messages between them. When
  you call another computer on your modem, the
  two modems must handshake to synchronize
  their responses.

intelligent terminal Ñ A smart terminal.

interactive question and answer sequence Ñ Ac-
  cess control system using a random list of
  questions. Because of their personal nature, the
  answers should be known only by the correct
  user and the system itself, thus authenticating
  account ownership.

Internet Ñ A very large network that connects just
  about any type of computer together. It
  supports e-mail, file transfer protocol (FTP),
  and remote login (telnet).

interoffice telephone Ñ A telephone not able to
  call the outside world. Or one which only seems
  to be so because the security code is not known.

iron box Ñ Perhaps not too accurate a name, since
  any hacker falling into a literal iron box would
  certainly know about it! An iron box is a
  restrictive or otherwise special environment set
  up on a system to trap unwary hackers into
  staying on the line long enough to trace. The
  trap may be a simulation of the actual system,
  or an abundance of groovy text files to read, or
  something simple like slowing down the
  system to a crawl.

ISIS Ñ Investigative Support Information System,
  used by the FBI as a massive database of
  important ongoing investigations. Every piece
  of known data about a case is entered, which
  can then be cross referenced and checked in-
  stantly.

Joe Ñ An account which has the username, or a
  variation of the username, as the password

  (regardless of whether that username is, in fact,
  ÒJoeÓ). Joe accounts have been called the Òsingle
  most common cause of password problems in
  the modern world.1Õ

LAN Ñ Local Area Network. A network that is
  linked locally, that is, within the same room, the
  same building, or perhaps between adjacent
  buildings. Usually machines in a LAN are
  connected via cables (such as in an office).
  Contrast with WAN.

letterbomb Ñ A piece of e-mail that contains live
  data, with the purpose of causing harm to the
  recipientÕs system. Might also be called a
  nastygram.

limited-use passwords Ñ A passwording system
  that combines the standard reusable password
  with once-only codes. These passwords may
  only be used a set number of times, or until a
  certain date.

line Ñ Pairs of connecting wires from a telephone
  to a central office. Also, loop, telephone line.

Listserv Ñ A program available on many B1TNET
  computers that sends mail and files to other
  computers. For example, if you want to start a
  mailing list, the Listserv would send the files
  you    want mailed     to  the  appropriate
  destinations.

live data Ñ Information in a data file which, under
  certain circumstances,  gets  interpreted as
  instructions to the computer. For example: On
  the Apple lie it is possible to turn an innocuous
  REM statement in an Applesoft BASIC program
  into a nightmare. Slip a Control-D into the REM
  so that when someone lists the program the AD
  will be printed on the first screen column. An~
  DOS command following that character will be
  executed. One could write a program that does
  nothing, but if anyone tries to list it, their disk
  gets initialized. More commonly, one thinks
  live data as control instructions to the terminal.

log Ñ A record kept of computer activity; may
  printed or stored to disk. System operators

  fond of reading through their logs to spot
  hacker activity. If you find one detailing your
  exploits, youÕll want to remove the incriminat-
  ing parts of it.

login Ñ To gain access to a computer, usually by
  entering the required username and password.

logic bomb Ñ A subversive piece of code in an
  application program that is executed when
  specific conditions hold true. A disgruntled
  employee might, before quitting his job, insert a
  line that says, ÒIF Joe SmithÕs account is deleted
  from  the system THEN  instruct payroll
  program to combine all paychecks into one and
  mail them to Joe Smith.Ó A logic bomb is also
  called a time bomb.

lounging Ñ See passive computing.

macro Ñ A keystroke or short name that is used to
  reference a longer piece of text or a series of
  instructions. For example, if you were writing a
  book about Hieronymous Bosch, you might set
  up a macro in your word processor to insert his
  name whenever you typed ÒAlt-H.Ó

modulation Ñ A process of loading a voice or other
  signal (wave) on a much higher frequency
  carrier wave. When a modem modulates your
  data as you type on your keyboard, it is
  converting the computerÕs digital pulses into
  frequencies within the audio range that the
  telephone transmits.

  odem Ñ MOdulator-DEModulator A device that
  modulates computer data into a format that can
  be sent through telephone wires, and can
  demodulate information that has been sent to it
  from another computer.

  S-DOS Ñ Generic version of PC-DOS, operating
  system software that runs on IBM PCs, clones
  and compatibles.

   TICS Ñ Short for MULTiplexed Information
  and Computing Service. An antique operating
  system that was built with security in mind.

multiplexing Ñ The use of different modulating
  frequencies for the simultaneous transmission
  of signals.

NCIC Ñ National Crime Information Computer,
  run by the FBI and containing information
  about stolen vehicles, missing and wanted
  persons, and arrest records. NCIC is linked
  with TECS Ñ the computer system of the
  Treasury Department Ñ as well as many state
  computers.

net Ñ Short form of network. Often used as part of
  words that refer to a specific network, such as
  the Internet.

network Ñ Two or more machines connected
  together for the purpose of exchanging data.

newsgroup Ñ A section of USENET devoted to the
  discussion of a particular topic.

node Ñ An individual machine (such as a
  computer or printer) that is connected to other
  machines in a network.

OCIS Ñ Organized Crime Information Systems,
  run by the FBI. Allows FBI field offices in
  separate locations to read and share informa-
  tion collected.

once-only codes Ñ A password that can only be
  used for one access.

operating system Ñ (Abbreviated OS). The control
  program of the computer which oversees how
  the system interfaces with the user and
  peripherals. Examples: DOS, MULTICS, MS-
  DOS, PC-DOS, PRIMOS, UNIX, VMS.

OS Ñ Operating System.

PAD Ñ Packet Assembler/Disassembler.

PABX Ñ Private Automatic Branch eXchange. A
  PAX with outside-dialing capabilities.
packet assembler/disassembler Ñ One of the node
  computers of a public data network.

packet switching Ñ A method of transmitting data
  along computers in a network. Each in-
  termittent computer is a PAD that receives
  chunks of data (128 bits long, following the X.25
  standard) and routes them onward along a path
  to the receiving computer.

parser Ñ A program that looks at some inputted
  text and tries to make sense of what it means.
  For instance, when you are using MS-DOS, you
  might type Òdel filename.Ó The parser inside
  MS-DOS figures out that what you want to do
  is erase the file called Òfilename.Ó A parser in an
  adventure game looks at commands such as
  ÒWalk to the door and knock on it,Ó and, if it
  was a good parser, would, for example,
  interpret the word ÒitÓ as referring to the door.

passive computing Ñ To monitor the contents of a
  computer screen through surreptitious means,
  using one of several methods such as Van Eck
  phreaking, or cabling the target computer to a
  second, secret monitor or VCR. Also, lounging.

pass phrase Ñ A series of words or syllables used
  for access control instead of a password.

password Ñ A word, phrase or other series of
  characters needed as part of the login proce-
  dures to access a computer system.

FAX Ñ Short for Private Automatic eXchange. A
  network of phones, not connected to outside
  lines. Used for faster and more secure com-
  munication.

PBX Ñ Short for Public Branch eXchange. A net-
  work of telephones, each equipped with its own
  switching arrangement, instead of requiring
  switching to be  done from a separate
  switchboard. Multiple phone numbers may
  ring each phone, and special function buttons
  are pressed on the telephone to either answer a
  call or transfer it to another telephone.

PC-DOS Ñ Operating system supplied by IBM for
  use with its personal computers.

PDN Ñ Short for Public Data Network.

phreak Ñ One who hacks the telephone system,
  usually to obtain free long distance calling and
  other services such as conference calling. In the
  original sense, phreaks used blue boxes, black
  boxes, green boxes, etc. Ñ specific pieces of
  hardware they had built to generate signals that
  would cause the phone network to do their
  bidding. The phone companies have taken
  precautions and nowadays the boxes will
  usually not work (and will usually get you
  arrested). Phreaking has become more code-
  oriented; stealing calling card numbers and
  otherwise charging phone perks to anotherÕs
  bill. Phreaking is related to hacking yet it is
  entirely different, a field of expertise unto itself.
  It has its own set of rules and jargon, and even a
  knowledgeable hacker who stumbles upon a
  phreak BBS is likely to be confused by the
  discussion. As they say, itÕs good to know a
  foreign language. For hackers, that language is
  phreak.

piggybacking Ñ In the physical sense, to get into a
  locked building by following in another person
  who has the key, card, or security clearance to
  enter. In the computing world, to login to a
  system  by  tapping  into another  userÕs
  communication with the computer. Usually
  done at the end of the userÕs call, and usually by
  chance, piggybacking can only be done when
  the computer doesnÕt realize that the first
  person has disconnected.

plaintext Ñ In encryption, the message (or file) that
  is encoded.

PLE Ñ Public Local Exchange. A local network of
  telephones usually  in separate buildings,
  houses or offices, and operated by an outside -
  phone company.

post Ñ To publish a letter, article, essay, story,
  graphic image, computer file or whatever Ñ
  but usually a letter or article Ñ electronically,
  by sending it to the public message area of a
  BBS or newsgroup.

PPN Ñ Project-Programmer Number. The TOPS-lO
  operating system used PPN to refer to a users

  ID number. PPM may at times be applied to

  other systems.

pps Ñ Pulses Per Second.

premises wiring Ñ The wires inside a building
  that are used to connect telephones to phone
  company lines.

PRIMOS Ñ An operating system for PRIME
  computers.

process Ñ A program that a computer is currently
  running.

process command Ñ A command to the operating
  system that requests a listing of all active
  processes. For instance, under UNIX one can
  type Òps -fÕ to see what everybody else logged
  on is doing.

protocol Ñ A set of rules used by software to in-
  teract with hardware. When two pieces of
  hardware must interact (such as when two
  modems connect), they must follow the same
  protocol, else communication between them
  will be impossible.

public data network Ñ A network, such as Telenet
  or Tymnet, that uses packet switching to con-
  nect computers; generally follows an interna-
  tional standard called X.25.

pulse Ñ A momentary flow of current, character-
  ized by a sharp rise and fall.

pulse frequency Ñ Number of pulses per second.

receive only telephone Ñ A phone that does not
  have a ringing circuit, and probably doesnÕt
  have a dial or keypad; cannot normally be used
  for placing calls. These can be found at public
  fax machines and  some automatic teller
  machines. A hacker would whip out his tone
  generator, hook it up to the telephone, and
  immediately call China.

reverse social engineering Ñ Tactic whereby the
  system user contacts the hacker for advice, and

  in the process of problem-solving, divulges
  confidential data.

root Ñ The superuser account, the top level of a
  hierarchical directory structure, or, in pro-
  gramming, the top node of a tree. For hacking
  purposes, we talk about the superuser aspect of
  it. It is often the hackerÕs goal to obtain root
  access to a system.

salami technique Ñ A method used to steal large
  sums of money over a long period of time,
  based on the assumption that little amounts
  wonÕt be missed. A computer that handles fi-
  nancial transactions is reprogrammed so that
  when fractions of pennies accrue in an account
  due to interest earned, those fractions are
  rounded down, and are placed into a dummy
  account. The criminal then makes off with the
  account.

scavenging Ñ To look through garbage bins in
  search of discarded, but still useful, informa-
  tion. Also, trashing.

script Ñ A command file that is executed auto-
  matically following handshaking by the callerÕs
  communications software; eliminates the need
  for the caller to remember his or her terminal
  type, login procedures, and whatever other
  input is required by the remote computer.

security through obscurity Ñ Here is a prelogin-
  message that exemplifies the opposite of secu-
  rity through obscurity: ÒThanks for calling Hey
  There Travel Agency Network. Please enter
  your five character password in the form ABC-
  12 where ABC stands for uppercase letters and
  12 stands for digits. If you need help, call
  Cheryl in data processing at (818)-XXX-XXxx.Ó
  Obviously there are a lot of security holes in
  this message. One would want to obscure it, by
  changing it all to one cryptic character, such as
  >. Security through obscurity can also refer to
  known bugs being left undocumented in the
  hopes that no one discovers them.

serial Ñ Passing information one bit at a time in
  sequential order.

shell Ñ An interface or command interpreter be-
  tween the  user and computer. Basically,
  whenever you input a command to a computer
  you are using some kind of shell.

shoulder surfing Ñ Finding out what a user is
  typing by looking over his or her shoulder, and
  watching the keyboard or monitor.

simplex Ñ One-way communications. (Compare
  with duplex.)

simulation Ñ A program set up by a hacker that
  mimics a legitimate aspect of the system, such
  as login screens.

smart terminal Ñ A terminal that has memory,
  editing commands, graphics, computational
  ability, security features, or is somehow oth-
  erwise a computer in its own right, and not just
  the input/output to a mainframe. Also called
  an intelligent terminal.

social engineering Ñ To use lies, deceit, play
  acting and verbal cleverness to trick a legiti-
  mate user into divulging the secrets of the sys-
  tem.

source code Ñ The list of instructions that a
  programmer types in that make up a computer
  program. This list is the ÒsourceÓ text that the
  computer will use when it translates the
  program into machine language.

stand-alone Ñ A computer or computer system
  that will operate without requiring additional
  equipment. A terminal is not a stand-alone
  device, since it must be connected to a
  computer for it to work. A Macintosh is a stand-
  alone device.

superuser Ñ The sysop, system administrator
  (sysadmin) or system manager, or any person
  who has no restrictions on usage on a machine.
  The superuser can create and delete accounts,
  view and change passwords and files, and is
  usually responsible for machine maintenance.

superzap Ñ To use special debugging or computer
  maintenance software tools to modify data.
  Usually to do so constitutes a security breach,
  or in the very least, violates the intended usage
  of the software one is altering.

switch Ñ To make a connection; or a system of
  connecting pairs of telephone lines. In surveil-
  lance, the redirection of output of two or more
  cameras to the available viewing monitors.

startup file Ñ A file that is executed when a com-
  puter is booted, or when one logs into an ac-
  count. Usually this is a plain ASCII text file
  containing shell commands which are run as a
  batch. On MS-DOS and PC-DOS machines it is
  the AUTOEXEC.BAT. UNIX uses .login (Òdot
  loginÓ).

sysadmin Ñ SYStem ADMINistrator. The overseer
  of a computer or network.

sysop Ñ SYStem OPerator. The person who takes
  care of and controls a BBS. The people who help
  the sysop are Òco-sysops,Ó or simply ÒcoÕs.Ó
  Pronounced Òsis-opÓ or Òsy-zop.Ó Often written
  as ÒSysOpÓ, and sometimes as Òsys-opÓ though
  this latter version is pretty lame.

talk mode Ñ To engage in on-line conversation
  with another user. What you type appears not
  only on your screen, but on his or her screen as
  well, and vice versa. If you were on a UNIX
  system and you knew that user Smuggy was
  logged in also, you would type Òtalk smuggyÓ
  and Smuggy would receive a message saying
  you wished to talk. Smuggy would respond
  with Òtalk yourname,Ó and the conversation
  would begin. In the BBS world, this is more
  commonly known as chat mode.

TAP Ñ Technological Assistance Program.

telnet Ñ A set of protocols used to access one
  machine through another. There are two types
  of programs used to do this. One, called telnet~
  establishes a VT100 type terminal emulation to
  the remote computer. The second, TN327
  establishes a full screen connection.

terminal Ñ Usually refers to a dumb terminal. In
  general, it is a combination input/output de-
  vice (a monitor and keyboard) connected to a
  remote computer.
TG Ñ Technical Guide.
tiger team Ñ A hacker or group of hackers who are
  engaged by an organization to find the security
  flaws in that organizationÕs computer system.
tone generator Ñ A device which includes two
  exterior components Ñ an acoustic coupling
  device and a telephone keypad Ñ with interior
  electronics that generate tones needed to
  operate a telephone. Often seen as a portable
  tone dialer, these devices are small enough that
  they will generally include a clip so that they
  can be hooked to oneÕs belt and easily carried.
  Also called Òtone dialer.Ó
trapdoor Ñ An undocumented way of gaining
  access to a computer system, usually thought of
  as a method of entry put in by a system
  programmer who wants to break into the
  computer after he is no longer employed by the
  company. A trapdoor may also lead to hidden
  areas of a system. A different kind of trapdoor
  may be unintentional; for example, a laxness in
  encryption procedure that allows one to deter-
  mine the plaintext without knowing the key.
  Synonym for back door.
tracking Ñ An investigatorÕs use of system logs
  and other audit trails to look and see where a
  hacker has been and what the hacker has done.
trashing Ñ To scavenge through the garbage of a
  business or organization, in the hopes of
  finding useful information, discarded manuals
  and the like.
Trojan horse Ñ A section of code hidden inside an
  application program that performs some secret
  action.
trusted hosts Ñ On some UNIX implementations,
  it is a list of other computers and users who
  require no password for entry.

TSR program Ñ Short for Terminate and Stay
  Resident program. A TSR program is one that is
  put into memory and stays there, even after

  other programs are loaded in. The TSR usually
  stays ÒhiddenÓ in the background until a person
  or the computer decides to use it. For example,
  a program to keep track of what keys are being
  pressed might be loaded into memory as a TSR.
  As the user switches from one application to the
  next, the TSR continues to run silently in the
  background, capturing keystrokes.

UNIX Ñ An operating system originated by Ken
  Thompson and Dennis Ritchie at the Computer
  Research Group at Bell Labs. True hackers, they
  wrote what would become one of the most
  predominant operating systems so they could
  play Space Travel without getting a jerky
  response from the MULTICS time-sharing
  system they had been forced to use.

USENET Ñ A huge Internet-based message ex-
  change. Users from all over the world read and
  exchange news, notes, comments, stories, files,
  humor and help on all topics under Ñ and
  above Ñ the sun.

username Ñ The name one uses on a computer
  network or system to identify oneself. Usually it
  is some variation on the personÕs real name.

vandal Ñ A cracker, and probably a not-too-tal-
  ented one, who tries to delete files, crash sys-
  tems, leave nasty messages everywhere and
  generally is a big pain in the ass.

virus Ñ A worm implemented as a Trojan horse
  that contains a logic bomb.

VMB Ñ Voice Mail Box. Voice mail is a comput-
  erized phone answering setup that stores in-
  coming messages in digitized form, on disk.

VMS Ñ Virtual Memory System, the operating
  system used on VAX minicomputers, made by
  DEC.

WAN Ñ Wide Area Network. A network where
  the linked machines are greatly separated from
  each other, usually not within walking distance.
  Computers in a WAN are generally connected

  via phone lines (such as Internet). Contrast with
  LAN.

Warez dOOd Ñ A silly name for people who trade
  or sell pirated software. Warez dOOd = (Soft)
  wares dude.

WATS Ñ Wide Area Telecommunications Service.
  Service which allows calling within a (possibly
  interstate) geographic region, often toll free.

worm Ñ A program whose purpose is to
  reproduce. A worm will copy itself endlessly
  into multiple directories and onto any disk that
  presents itself.


 


         Terms
        -------------------------------------------------------------

        ALOHAnet - Norm Abramson wanted to    [Abramson on surfboard]
        surf - so he moved to Hawaii in 1969.
        Abramson wanted to network with the other islands - so he
        built the ALOHAnet in 1970. From the University of Hawaii,
        Abramson connected computers over a network of radio
        transmitters using a protocol telling the computers how to
        share the airwaves. more of the story...

        ARPA - Advanced Research Projects Agency, founded in 1957 in
        response to the Russian scientists beating our scientists in
        putting a satellite into orbit. more of the story...

        ARPAnet - Advanced Research Projects Agency Network. Bob
        Taylor came up with the idea of networking all the
        ARPA-funded computers together so he wouldn't have to change
        seats. more of the story...

        Bandwidth - how much stuff you can cram onto the network. A
        wider bandwidth means more information in a shorter amount
        of time.

        BBN - Bolt, Beranek and Newman, in Cambridge, MA  [BBN group]
        - founded by three partners in the 1950s as a
        consulting business in acoustic engineering. BBN shifted its
        business to computers as they became more important. In
        1969, BBN was awarded the contract to build the first IMPs.
        more of the story...

        Browser - software for navigating the Web, retrieving
        documents and other files, and displaying them on the user's
        screen. Two of the most popular browsers are Netscape
        Navigator and Microsoft Internet Explorer.

        Bulletin Board System (BBS) - the cyberspace equivalent to
        the office bulletin board, a BBS is software that allows
        users to post and read messages left by other users.
        Bulletin Board Systems were very popular in the 1980's when
        computer enthusiasts set up their own systems on personal
        computers. more of the story...

        Domain Name - When the keepers of the Internet realized that
        the number of computers on the network was getting too much
        to handle with simple computer names, they came up with a
        new addressing system. They added the school, organization,
        or company name and a domain identifier to tell if it was
        commercial (com), educational (edu), or something else (org,
        etc.). The domain for the PBS Web server is "pbs.org" and
        the full address "www.pbs.org" is the domain name. Other
        countries have an additional identifier to tell which
        country it comes from - for example, ".uk" means it's
        located in the United Kingdom.

        Ethernet - a networking technology to connect computers over
        a local area network invented by Bob Metcalfe and David
        Boggs at Xerox PARC. Named after the invisible, massless
        substance that 19th century scientists believed filled the
        universe. more of the story...

        FTP - File Transfer Protocol. One of the first applications
        developed for the ARPAnet, it's still used to send and
        retreive files across the Internet.

        Graphical User Interface (GUI) - a visual, icon-driven
        interface for an operating system or other application. A
        nice litle acronym pronounced "gooey."

        Host - Just like a party's host is responsible for all the
        guests, a computer host takes care of any other computers
        visiting over a network. In the early days of networking,
        any computer was a potential host, so now any computer
        connected to a network is called a host.

        HTML - HyperText Markup Language. Publishers have always
        needed to write down instructions to the printer telling
        them how they wanted the document to look. Eventually,the
        printing business developed a standard set of shorthand
        "markup" instructions or "tags". On the Web, publishers use
        a Hypertext Markup Language to instruct Web browsers how the
        document should look. Berners-Lee came up with the first set
        of HTML tags using a tag style defined by the OSI for their
        Standard Generalized Makup Language (SGML). The HTML
        standard is currently defined and controlled by the World
        Wide Web Consortium.

        HTTP - Hypertext Transfer Protocol. This is a set of
        instructions on how Web browsers and servers talk to each
        other.

        Hypertext - a document formatting that allows documents to
        be linked by making certain words or phrases "clickable."
        When the link is followed, the information on the second
        document is related to the word in the first document.
        Hypertext is the formatting used on the World Wide Web.

        IMP - Interface Messaging Processor  [installing IMP at UCLA]
        - these were the minicomputers that
        connected each node on the ARPAnet to the network. Built by
        BBN, each was a refrigerator-sized Honeywell DDP-516
        computer with a whopping 12k of memory. more of the story...

        Internet - An internet is a group of networks connected
        together. The Internet (note the capital "I") refers to the
        global connection of networks around the world.

        InterNIC - a collaborative project by Network Solutions,
        Inc., and AT&T (supported by the NSF) which provides four
        services to the Internet community. A "white pages"
        directory of domain names, IP addresses, and publicly
        accessible databases, domain name and IP address
        registration, support services for the Internet community,
        and an online publication summarizing information of
        interest to the online community.

        IP - Internet Protocol, a protocol telling how packets on an
        internet are addressed and routed. The second part of
        TCP/IP.

        Java - a high-level, object oriented programming language
        developed by Sun Microsystems that runs on most operating
        platforms. One of the original purposes of the language was
        to create a common language for all the "smart" appliances
        in the house. The ultimate in cross-platform, Java was going
        to let your TV and toaster speak the same language. Its new
        mission is to provide a language that programmers can use to
        write applications anyone can use on any computer. more of
        the story...

        Javascript - A scripting language developed by Netscape
        Communications to add interactivity to Web pages. It really
        has little to do with Java, but Javascript is supposed to
        work across platformas and browsers.

        Killer Application - Every step in the development of
        computers had a special application that made that step work
        and succeed - a killer app. For the personal computer it was
        the spread-sheet, and for the Internet it was email.

        Local Area Network (LAN) - a group of computers, usually all
        in the same room or building, connected for the purpose of
        sharing files, exchanging email, and collaboration.

        Mainframe - a large, multiuser computer. Before personal
        computers were available, businesses and universities
        purchased large and expensive mainframes and housed them
        away in large, air-conditioned rooms.

        Metcalfe's Law - Metcalfe believes that a network's worth is
        directly related to the number of people on the networking.
        In the language of math, his law says "where N is the number
        of nodes, the power of a network is N squared."

        Modem - modulator/demodulator - a device that     [old modem]
        converts digital (binary) signals from a computer
        into analog signals suitable for transmission over a phone
        line. On the other end, another modem it receives analog
        signals from a phone line and translates the analog signal
        back into digital bits.

        MOSAIC - Soon after Marc Andreessen saw what the new World
        Wide Web could do in 1992, he thought a graphical interface
        for the browser would let everyone use the Web. He and seven
        other student programmers at the University of Illinois
        wrote the world's frist graphics Web browswer, Mosaic, in
        1992. more of the story...

        NSFnet - A wide-area network developed by the National
        Science Foundation (NSF) in 1985. NSFnet replaced ARPAnet as
        the main government network linking universities and
        research facilities in 1990.

        Node- a processing location on a network.

        Packet - to send a message over a packet-switched network,
        the whole message it first cut up into smaller "packets" and
        each is numbered and labeled with an address saying where it
        came from and another saying where its going.

        Packet switching - the technology that made large-scale
        computer networking possible. Instead of a dedicated
        connection between two computers, messages are divided up
        into packets and transmitted over a decentralized network.
        Once all the packets arrive at the destination, they are
        recompiled into the original message. more of the story...

        Protocol - format or set of rules for communication, either
        over a network or between applications.

        Router - a descendent of the IMP, a router directs packets
        between separate local area networks. To make the connection
        more efficient, a router reads each packet's header and
        directs it in the fastest direction. more of the story...

        Search Engine - a program accessible on the Web which has a
        catalog of scanned Web sites in a large database. The user
        enters a list of keyword or search parameters, and the
        search engine creates a list of matches for the user to
        choose from.

        TCP/IP - Transmission Control Protocol/Internet Protocol,
        first defined by Vint Cerf and Bob Kahn in 1973, the
        protocol made the Internet possible and has become the
        default network protocol around the world. more of the
        story...

        TELNET - Terminal Emulation. Telnet allows [Vint Cerf telnet]
        a user at a remote computer to log on to
        another computer over a network and enter commands at a
        prompt as if they were directly connected to the remote
        computer.

        Unix - an operating system developed by Kerrighan and Richie
        at AT&T Bell Labs in the late 1960's. It was written
        entirely in the C programming language, which made it easier
        to port to other platforms. It is still the primary
        operating system for the biggest servers on the Internet.

        URL - Uniform Resource Locator, the address of a document or
        other resource reachable on the Internet. A URL has three
        components, specifying the protcol, server domain name, and
        the file location. For example,
        "http://www.pbs.org/nerds201/index.html" specifies using the
        HTTP protocol (others include ftp or gopher), on the
        www.opb.org server, and the file "/nerds201/index.html."

        Usenet - A worldwide bulletin board system that can be
        accessed through the Internet or through many online
        services. The USENET contains more than 14,000 forums,
        called newsgroups, that cover almost every imaginable
        interest group. Created years before the Web, It is still
        used daily by millions of people around the world.

        World Wide Web (WWW) - The protocol devised and implemented
        by Tim Berners-Lee in 1990 to help researchers at CERN share
        information across a diverse computer network. more of the
        story...

        Xanadu - a networked, nosequential, hyperlinked system of
        documents and multimedia objects first proposed by Ted
        Nelson in 1965. Nelson's system was similar to the World
        Wide Web, but included the ability to compose documents from
        sections scattered around the network and a method of making
        micropayments to copyright holders. more of the story...

        Xerox PARC - The Palo Alto Recearch Center was built by
        Xerox in the early 1970s to keep them ahead of the other
        office equipment companies in developing the office of the
        future. It is the location of many of the innovations that
        have changed the computer and communications. more of the
        story...

                   Next Section: Internet Timeline[arrow]





Acronyms

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

 AAM   Area Administrative Manager
 ABC   Activity Based Costing
 ABD   America's Business Division, domestic regional business center
 ABIC  Advanced Bi-CMOS
 ABM   Activity Based Managememt
 ABP   Advanced Bus Products.
 ABS   Anti-lock Braking System
 ABT   Advanced BiCMOS TTL, mix variable by vendor
 AC    Advanced CMOS with CMOS-level input threshold
 ACA   Assigned Corporate Account
 ACC   Accumulator Accuracy Control Character
 ACCORDAutomated Customer Communications Real-time Debits
 ACL   Advanced CMOS Logic, TI's version of FACT
 ACLV  AutoCLaVe (REL test)
 ACM   Association for Computing Machinery
 ACMOS Advanced CMOS
 ACQ   FACT Quiet Series with CMOS-level input threshold
 ACT   Advanced CMOS with TTL-level input threshold (NOT bipolar)
 ACTQ  FACT Quiet Series with CMOS-level input threshold (NOT bipolar)
 ACU   Airborne Control Unit
 AD    Area Director
 ADAM  Assigned Distributor Account
 ADC   Analog to Digital Controller
 ADP   Automatic Data Processing
 ADSM  Area Distributor Sales Manager
 AES   Auger Electron Spectroscopy
 AF    Audio Frequency
 AI    Artificial Intelligence
 ALIC  Advanced Linear Integrated Circuit
 ALR   Assembly Level Reliability
 ALS   Advanced Low Power Schottky Logic
 AMG   Alternating Metal Ground
 AMHS  Automated Material Handling Systems
 AMM   After Market Manufacturer
 AMR   Automated remote Meter Reading
 AND   Advanced Network Devices
 ANSI  American National Standard Institute
 AOP   Annual Operating Plan, superseded by SBP1
 AOPU  Annual Operating Plan Update, superseded by SBP2
 AOQL  Average Outgoing Quality Level
 AP    Asia Pacific
 APL   Approved Product List
 APICS American Production and Inventory Control Society
 APM   Advanced Power Management
 APPG  Automatic Pad Placement Generator
 APQ   All Parts Qualified (date)
 AQL   Acceptance Quality Level
 AQP   Advance Quality Planning
 ARAM  Audio RAM (defective DRAM)
 AP/PO Accounts Payable/Purchase Order
 ARO   After Receipt of Order
 ARP   Address Resolution Protocol
 AS    Advanced Schottky
 ASAP  As Soon As Possible
 ASCII American Standard code for Information Interchange
 ASD   Analog Software Development; Analytical Software Development
 ASIC  Application Specific Integrated Circuit
 ASIM  Application Specific Integrated Module
 ASIP  Advanced System and Interface Product
 ASN   Advanced Shipping Notice
 ASP   Average Selling Price
 ASPC  Automated Semiconductor Planning and Control
 ASQC  American Society for Quality Control
 ASSP  Application Specific Standard Parts
 ASSY  ASSemblY
 ATE   Automated Test Equipment
 ATM   Area Technical Manager
 ATS   Available To Sell
 ATSP  Application Targeted System ProductAT&T -QR; AT&T Quality Registrar
 AVI   Audio Video Interleaved
 AWB   AirWayBill
 AWS   Alternative Work Schedule
[Image]  Top

 B/L   Backlog
 BASIC Beginners All-purpose Symbolic Instruction Code
 BBS   Bulletin Board System
 BC    Business Center
 BCAE  Business Center Applications Engineer
 BCD   Binary Coded Decimal
 BCM   Business Center Manager
 BCME  Business Center Marketing Engineer
 BCP   Biphase Communications Processor
 BCT   BiCMOS TTL, mix of bipolar and CMOS depends on vendor
 BCU   Business Center Unit
 BE    Break Even
 BEM   Building Emergency Manager
 BI    Burn-In
 BIC   Best In Class
 BiCMOSPart Bipolar, Part CMOS, percent mix variable
 BiFET Bipolar Field Effect Transistor
 BIOS  Basic Input/Output
 BIST  Built In Self Test
 BOE   Buffered Oxide Etch
 BOF   Business Opportunity Forecast
 BOM   Business Office Manager
 BP    Business Planning
 BPP   Biased Pressure Pot = Biased ACLV
 BPS   Bit Per Second
 BPSG  Boron Phosphor Silicate Glass
 BS    Build Sheet
 BUM   Business Unit Manager
 BTL   Backplane Transceiver Logic, bipolar process
 BTW   By The Way
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 CA      Corrective Action
 CAC     Career Action Center
 CAD     Computer Aided Design
 CAE     Computer Aided Engineering
 CAI     Computer Aided Instruction
 CAM     Computer Aided Manufacturing
 CAM     Content Addressable Memory
 CAN     Car Area Network
 CAPS    Commute Alternative Program System
 CAO     Chief Administrative Officer
 CASE    Computer-aided Software Engineering
 CAT     Corporate Action Team (to analyze Employee Survey Results)
 CATV    Cable Television
 C & C   Communications and Computing (Division)
 C&T     Computing & Telecommunications
 CBD     Coefficient of Bureaucratic Drag
 CBI     Critical Business Issue
 CBS     Corporate Business Systems
 CBT     Computer Based Testing
 C of C  Certificate of Compliance
 CCD     Charge Coupled Device
 CCG     Communications and Computing Group
 CCIM    Corporate CIM
 CCM     Configurable Controller Methodology
 CCV     Closed Circuit Voltage
 CD      Collision Detection
 CDA     Clean Dry Air; Corporate Design Automation
 CDE     Common Design Environment
 CDF     Customer Drawing File
 CDI     Compact Disk Interactive
 CDROM   Compact Disc Read Only Memory
 CEG     Computer Enchancement Group
 CEO     Chief Executive Officer
 C & F   Cost and Freight
 CFAP    Customer Forecasting Automation Process
 CFO     Chief Financial Officer
 CGI     Common Gateway Interface
 CHD     Corporate Help Desk
 CHIPS   Center for Health Improvement and Personal Success
 CIA     Cash In Advance
 CIF     Cost, Insurance and Freight
 CIM     Computer Integrated Manufacturer
 CIRM    Certification in Integrated Resource Management
 CIS     Contact Image Sensor
 CISC    Complex Instruction Set Computing
 CLASIC  Custom Linear ASIC
 CLAY    Configureable Logic Array
 CLD     Custom Logic Device
 CLIC    Consumer Linear Integrated Circuit (previous NSC product group)
 CM      Configuration Management
 CMF     Customer Master File
 CMIP    Common Management Information Protocol
 CMOS    Complimentary Metal Oxide Silicon
 CMR     Customer Material Return
 CMS     Conversational Monitor System
 CMYK    Cyan-Magenta_Yellow_Key (usually black)
 CODEC   COmpressor/DECompressor
 COMETS  Comprehensive On-line Manufacturing Engineering Tracking System
 COO     Chief Operations Officer
 COP     Calculator On Processor
 COS     Cost Of Sales
 COT     Customer Owned Tooling
 CP      Control Program
 CPC     Central Production Control
 CPD     Power Dissipation Capacitance
 CPE     Customer Premise Equipment
 CPK     Process Capability Index
 CPL     Certified Parts List; Customer Product List
 CPM     Critical Path Method; Corporate Product Manager
 CPN     Customer Part Number
 CPR     Continued Processing Request
 CPS     Corporate Planning System; Customer Profile System
 CPU     Central Processing Unit
 CQF     Customer Qualification Form
 CRC     Customer Response Center
 CRD     Customer Return Debits; Customer Request Date
 CRS     Capacity Reservation System; Channel Reservation System
 CRT     Cathode Ray Tube
 CS      Customer Service
 CSC     Customer Support Center
 CSD     Contract Sales Debits; Current Schedule Date
 CSMA    Carrier Sense Multiple Access
 CSMA/CD Carrier Sense Multiple Access and Collision Detection
 CSP     Contract Sales Price; Customer Specific Product
 CSTF    Corporate Strategy Task Force
 CT      Cold Test; Cycle Time; Computer Tomography (replacement for CAT)
 CTC     Career Transition Center
 CTG     Corporate Technology Group
 CTM     Customer

 CTP     Customer Tooled Products; Customization Technologies & Products
         (ASIC in LAN)
 CUBA    CUstomer Base Analysis
 CTO     Chief Technical Officer
 CY      Calendar Year
 CYA     Cover Your Assets
 CVD     Chemical Vapor Deposition
 CVP     Cooperative Vendor Program
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 DA    Design Automation
 DAC   Digital to Analog Converter
 DAM   Digital Answering Machine
 DARPA Defense Advanced Research Projects Agency (US government)
 DAS   Device Analysis Services; Data Acquisition System
 DASK  Digital Implementation for Amplitude Shift Keying
 DAT   Digital Audio Tape
 DBI   Database Interface
 DBU   Distribution Business Unit
 DCE   Data Communication Equipment
 DCF   Document Composition Facility
 DD    Defect Density
 DDI   Direct Data Interface
 DDS   Device Detail Sheet
 DE    Design Engineering
 DEC   Digital Equipment Corporation
 DECT  Digital European Cordless Telecommunications
 DESC  Defense Electronic Supply Commission
 DFT   Design For Test
 DHTL  Dynamic High Temp. Life (OPL)
 DI    Develop Inspect
 DLM   Dual Layer Metal
 DIP   Dual In-line Package
 DIW   Distributed Inside Wire
 DMA   Direct Memory Access
 DMD   Data Management Group
 DNA   Digital Network Architecture
 DNI   SunMicrosystem DECnet-compatible products
 DNR   Dynamic Noise Reduction
 DOA   Dead On Arrival
 DOD   Department Of Defense (US government)
 DOE   Design Of Experiments
 DOS   Disk Operating System for personal computer
 DP    Data Processing
 DPI   Data Processing Interface
 DPS   Desktop Personal Systems
 DPW   Die Per Wafer
 DRAM  Dynamic Random Access Memory
 DRC   Design Rules Check
 DSM   Distributor Sales Manager
 DS    Data Sheet; Development System
 DSO   Distributor Sales Out (resales)
 DSP   Digital Signal Processor
 DTAM  Distribution Total Available Market
 DTE   Data Terminal Equipment
 DTP   Data grade unshielded Twisted Pair; Data Transmission Products
 DTP   Desk Top Publishing
 DUT   Device Under Test
 DWF   Die in Wafer Form
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 EAO    European Automotive Operations
 EAP    Employee Assistance Program
 EB     East Bangkok assembly & test facility
 EBIC   Electron Beam Induced Current
 EBS    Electronic Build Sheet
 EC&I   Embedded Controllers & Imaging
 ECC    Engineering Computer Center
 ECD    Embedded Control Division
 ECG    Embedded Control Group
 ECL    Emitter-Coupled Logic, bipolar process
 ECLIPS Motorola's Advanced ECL
 ECN    Engineering Change Notice
 EDA    Electronic Design Automation
 EDB    Engineering Data Base
 EDI    Electronic Data Interchange
 EDIF   Electronic Data Interchange Format
 EDN    Electronic Design News
 EDP    Electronic Data Processing
 EDS    Energy Dispersive Spectroscopy
 EDX    Energy Dispersive X_ray Spectroscopy
 EEPROM Electronically Eraseable Programmable Read Only Memory
 EF     Early Failure
 EFR    Early Failure Rate
 EI     Environmental Improvement
 EIA    Electronics Industries Association
 EIAJ   Electronics Industries Association of Japan
 EISA   Electronics Industry Standard Architecture
 ELF    Extremely Low Frequency
 EM     Mallaca, Malaysia; ElectroMigration
 EMAIL  Electronic Mail
 EMC    ElectroMagnetic Compatibility
 EMI    Electromagnetic Interference
 EMS    Emission Microscope System
 EMU    EMUlator
 EOF    End Of Field
 EOL    End of Life; End of Line
 EON    Engineering Order Number
 EOS    Electrical OverStress
 EP     EndPoint
 EPROM  Eraseable Programmable Read Only Memory
 EPS    Earnings Per Share
 EPU    Evaluation and Programming Unit
 EQR    Electronic Industries Quality Registrar
 ERC    Engineering Response Center
 ERDM   Electronic Reliability Data Management
 ESA    Enterprise Systems Architecture
 ESCA   Electron Spectroscopy for Chemical Analysis
 ESD    Electro Static Discharge; Embedded Systems Division
 ERT    Emergency Response Team
 ESF    Executive Strategic Forum
 ESS    Environmental Stress Screening
 ET     Electric Test (before WS)
 ETA    Estimated Time of Arrival
 ETD    Estimated Time of Departure
 ETS    Educational Testing Society
 EUR    EURope
[Image]  Top

 F100KFairchild 100K ECL Logic
 FA   Failure Analysis
 FAB  FABrication (Plant)
 FACT Fairchild Advanced CMOS Technology
 FAE  Field Applications Engineer
 FAQ  Frequently Asked Question
 FASB Financial Accounting Standards Board
 FAT  Functionality Application Test
 FAX  Facsimile
 FCC  Federal Communications Commission
 FCS  Frame Check Sequence
 FCST ForeCaST
 FCT  FAST CMOS with TTL-level input threshold (NSC's is NOT bipolar)
 FCTA Higher speed version of FCT
 FCTB AMD29c8xx equivalent FCT
 FDC  Floppy Disk Controller
 FDDI Fiber Distributed Data Interface
 FEA  Finite Element Analysis
 FEP  Front End Processor
 FET  Field Effect Transistor
 FFF  Form, Fit, and Function
 FIBS Focused Ion Beam System
 FIFO First in First Out
 FISH First In, Still Here
 FIT  Failures In Time (Failures per billion operating device-hours)
 FLA  Four Letter Acronym; Five Letter Acronym
 FMC  Field Marketing Center; Fixed Manufacturing Costs
 FMEA Failure Mode Effect Analysis
 FMM  Field Marketing Manager
 FOB  Free On Board
 FOX  Field OXide
 FPA  Floating Point Accelerator
 FPLA Field Programmable Logic Array
 FRC  Fairchild Research Center
 FRP  Fast Reaction Program
 FRU  Field Replaceable Unit
 FS   Field Sales
 FSE  Field Sales Engineer
 FT   Final Test; Fast Test; Feed Through
 FTA  Field Target Account
 FTP  File Transfer Protocol
 FUD  Fear, Uncertainty, Doubt
 FY   Fiscal Year
 FYA  For Your Amusement
 FYI  For Your Information
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 G&A  General and Administrative
 GAAP Generally Accepted Accounting Principles
 GaAS Galluim Arsenide
 GAL  General Array Logic
 GDW  Gross Die per Wafer
 GE   GErmany
 GIC  Guaranteed Investment Contract
 GIGO Garbage In, Garbage Out
 GIF  Graphic Interchange Format
 GIP  Group Incentive Plan
 GL   General Ledger
 GLT  Guaranteed Lead Time
 GM   Gross Margin
 GMC  Global Marketing Council
 GML  Generalized Markup Language
 GNP  Gross National Product
 GOP  Gross Operating Profit
 GOS  Gate Oxide Short
 GP   Gross Profit
 GPIB General Purpose Instrument Bus
 GPM  Gross Profit Margin
 GPO  General Post Office
 GT   Greater Than
 GTO  Gradual Turn-On (circuit for reducing ground bounce)
 GUI  Graphical User Interface
 GV   Geometry Verification
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 HAST Highly Accelerated Stress Test
 HAWB House AirWayBill
 HC   High-speed CMOS with CMOS-level input threshold
 HCMOSHigh-speed CMOS
 HCT  High-speed CMOS with TTL-level input threshold (NOT bipolar)
 HDL  High Level Design Language
 HDTV High Definition Television
 HLL  High Level Language
 HMMP Hazardous Material Management Plan
 HP   Hewlett Packard
 HPC  High Performance Controller; High Performance Contacts
 HPS  High Performance System
 HR   Human Resources
 HRD  Human Resource Development
 HT   Hot Test
 HTH  Hope This Helps
 HTML HyperText Markup Language
 HTRB High Temperature Reverse Bias
 HTSL High Temperature Storage Life
 HTTP HperText Transport Protocol
 HV   High Voltage

 HVAC Heating, Venting, and Air Conditioning; High Voltage Alternating
      Current
 HW   HardWare
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 IBE   International Business Element
 IBEM  Intermediate Business Element Manager
 IBG   International Business Group
 IBM   International Business Machines (a company name or a PC type)
 IBR   International Business Review
 IC    Integrated Circuit
 ICC   Power Supply Current
 ICCD  Dynamic Power Dissipation Current (given in mA/MHz)
 ICCT  Additional ICC (IDD) due to CMOS input at TTL level
 ICMP  Internet Control Message Protocol
 ICR   Intelligent Character Recognition
 ICT   In-Circuit Tester
 ICU   Intensive Care Unit
 IDB   Integrated Database
 IDD   Power Supply Current (MOS)
 IDE   Integrated Drive Electronics
 IDS   Integrated Diagnostic System
 IEE   Power Supply Current ECL
 IEEE  Institute of Electrical and Electronic Engineers
 I/F   Interface
 IIH   Input Current High
 IIL   Input Current Low
 IIN   Input Leakage Current(if IIH=IIL)
 IIT   Integrated Information Technology
 ILD   Inner Layer Dielectric
 IMHO  In My Humble Opinion
 IMNSHOIn My NOT SO Humble Opinion
 INN   InterNational News
 IO    Input-Output
 IOH   Output Current High
 IOHD  Dynamic IOH (used ti guarantee CMOS line driving)
 IOL   Output Current Low
 IOLD  Dynamic IOL (used to guarantee CMOS line driving)
 IOS   Output Short Circuit Current
 IOZ   Output Current Tristate
 IOZT  I/O Current Tristate for Transceiver
 IP    Internet Protocol
 IPG   Innovative Products Group
 IR    InfraRed
 IrDA  Infrared Data Association
 IRQ   Interrupt Request Line
 IRR   Internal Rate of Return
 IS    Information Systems
 ISA   Internal Sales Administrator
 ISDN  Integrated Services Digital Network
 ISE   In System Emulator
 ISG   Information Systems Group
 ISIR  Initial Sample Information Report
 ISO   International Standards Organization
 ISP   Internet Service Provider
 I/T   In Transit
 ITR   Inspection Trouble Report
 IVHS  Intelligent Vehicle Highway System
[Image]  Top

 JANS Joint Army Navy Space
 JAP  JAPan
 JEDECJoint Electrical Defense Engineering Council
 JETAGJoint European Test Action Group
 JFET Junction Field Effect Transistor
 JIT  Just In Time
 JMI  Johnson Matthey Incorporated
 JPEG Joint Photographic Experts Group
 JV   Journal Voucher
[Image]  Top

 KEIPKey Employee Incentive Program
 KGD Known Good Die
[Image]  Top

 LA     Lot Acceptance
 LAN    Local Area Network
 LAT    Lot Acceptance Test
 LC     Letter of Credit
 LCC    Leadless Chip Carrier = LLCC
 LCD    Liquid Crystal Display
 LD     LeaD
 LDCC   LeaDed Chip Carrier
 LDO    Low-Dropout Regulator
 LED    Light Emitting Diode
 LERIC  Lite Repeater Interface Controller
 LIFO   Last In, First Out
 LLC    Logical Link Control
 LLCC   LeadLess Chip Carrier
 LNA    Low Noise Amplifier
 LOA    Leave Of Absence
 LOTS   Lot Order Tracking System (tracks WIP)
 LP     Late Programming
 LPCVD  Low Pressure CVD
 LRT    Lab Resource Team
 LSB    Least Significant Bit
 LS/LPS Low Power Schottky Logic
 LSI    Large Scale Integration
 L/T    LeadTime
 LT     Long Term; Less Than
 LTO    Low Temperature Oxide
 LVS    Layout Versus Schematic
[Image]  Top

 MA     Market Analysis
 MAC    Media Access Control
 MACSI  Media Access Controller and System Interface
 MAN    Metropolitan Area Network
 MAPL   Multiple Array Programmable Logic
 MARCOMMMARketing COMMunications
 MAU    Multi-station Access Unit
 MAWB   Master AirWayBill
 MBA    Master of Business Administration
 MBO    Management By Objectives
 MBNQA  Malcolm Baldridge National Quality Award
 MBPS   Megabits Per Second
 MBWA   Management By Walking Around
 MCA    Micro Channel Architecture
 MCC    Microelectronics and Computing Consortium
 MCP    Multi-Chip Package
 MCR    Materials Characterization Repository
 MCT    Micro Component Technology
 MECL   Motorola ECL
 MER    Material Engineering Requisition
 M&L    Materials & Logistics
 MET    Master Edit Table
 MFG    ManuFacturinG
 MFM    Major Failure Mode
 MH     Midgel Haemek
 MILAEROMILitary, AEROspace
 MIME   Multipurpose Internet Mail Extension
 MIPS   Million Instructions Per Second
 MIR    Managing Interpersonal Relationships
 MIS    Management Information System
 MIWU   Multi-Input WakeUp
 MMU    Memory Management Unit
 MOLE   Microcontroller On-Line Emulator
 MORE   Migrate Onwards to Real Expectations
 MOS    Metal-Oxide-Silicon, type of transistor structure
 MOSFET Metal-Oxide-Silicon Field Effect Transistor
 MPEG   Motion Picture Experts Group
 MPD    Memory Products Division
 MPL    Master Price List
 MPO    Master Purchase Order
 MPU    Microprocessor Unit
 MRC    Manufacturing Release Checklist
 MS     Mail Stop
 MSDOS  Microsoft's Disk Operating System
 MSA    Measurement System Analysis
 MSB    Most Significant Bit
 MSC    Marketing Status Code
 MSP    Military Special Products
 MSI    Medium Scale Integration
 MT     Medium Term
 MTBF   Mean Time Between Failures
 MTS    Member of Technical Staff
 MTTR   Mean Time To Repair
 MVS    Multiple Virtual Storage
 MUX    Multiplexer
[Image]  Top

 NABC   North America Business Center
 NAD    North America Division
 NDW    Net Die per Wafer
 NAUs   Network Addressable Units
 NBP    New Business Plan
 NBS    National Bureau of Standards
 NCSA   National center for Supercomputing Applications
 NCP    Network Control Program
 NDA    Non-Disclosure Agreement
 NET    Network Equipment Technologies
 NETBIOSNetwork Basic Input/Output
 NGP    Next General Product, internal code for advanced BiCMOS
 NFARS  Network File Access Routines
 NFC    Need For Change
 NFS    Network File System
 NFT    Network File Transfer
 NIC    Network Interface Controller
 NICE   NSC Integrated Customer Service Envelope
 NISO   N-well ISOlation (mixed signal)
 NIST   National Institute of Standards and Technology
 NIH    Not Invented Here
 NLM    NetWare-Loadable Module
 NMM    National Marketing Manager
 NMOS   MOS transistor with N-type channels N-channel Metal Oxide Silicon
 NOVA   NSC On- line Viewing Access system
 NPBA   New Products Business Analysis
 NPD    New Product Development
 NPEP   New Product Execution Plan
 NPI    New Product Introduction
 NPIM   New Package Introduction Method
 NPPRS  New Product Phase Review System
 NPS    National Planning System defines the strategic planning process
 NRE    Non-Recurring Engineering (charge)
 NS     National Semiconductor
 NSA    National Security Agency
 NSID   NSC internal part IDentification
 NSC    National Semiconductor Corp.
 NSQ    Non-Stop Quality
 NSR    Network Service Request
 NSCB   NSC Cebu, Philippines Site
 NSEM   NSC Malacca, Malaysia Site
 NSEP   NSC Penang, Malaysia Site
 NSFM   NSC S. Portland, Maine Site
 NSJK   NSC Chiba Shi, Japan Site
 NSSC   NSC Santa Clara, Ca site
 NSSG   NSC Singapore Site
 NSSL   NSC West Jordan, Utah Site
 NSTE   NSC Arlington, Texas Site
 NSUK   NSC Greenock, Scotland Site
 NSVM   Natioanl Shareholder Value Management
 NSQ    Non-Stop Quality
 NSVDT  Negotiating Skills Value Delivery Team
 NTPRS  New Technology Phase Review System
 NTS    Net Trade Sales
 NVD    Non-Volatile Device
 NVM    Non-Volatile Memory
[Image]  Top

 OBM Operations Business Manager, heads up production control
 OCR Optical Character Recognition
 OEM Original Equipment Manufacturer
 OLE Object Linking and Embedding
 OS  Operating System

 OSD Original Schedule Delivery, the % of orders we deliver when we said we
     would
 OSI Open System Interconnection
 OTP One-Time Programmable
 OV  Office Vision
[Image]  Top

 P & L Profit and Loss
 PA    Product Announcement
 PABX  Private Automatic Branch Exchange
 PAD   Packet Assembler/Disassembler
 PAE   Product Application Engineer
 PAL   Programmable Array Logic
 PAP   Price, Availability Process
 PAT   Plant Action Team; Profit After Tax
 PBC   Product Business Case
 PBID  PriceBook IDentifier
 PBT   Price Before Tax; Profit Before Tax
 PC    Personal Computer; Production Control
 PCB   Printed Circuit Board
 PCI   Peripheral Component Interconnect
 PCM   Pulse Code Modulation
 PCMCIAPersonal Computer Memory Card International Association
 PCN   Product Change Notice
 PCP   Personal Computer Peripheral(s)
 PCS   Personal Communication System
 PCTCP Personal Computer Transfer Control Protocol
 Pd    Period
 PDA   Personal Digital Assistance
 PDAL  Product Definition Approval List
 PDF   Product Discontinuance Form
 PDP   Product Development Plan
 PDS   Product Definition System
 PDT   Product Development Technology
 PE    Product Engineer(ing)
 PECL  Positive Rail ECL
 PECVD Plasma Etch CVD
 PEF   Process Experiment Form
 PEM   Product Engineering Manager
 PEP   Performance Enhancement Program
 PERL  Practical Extraction and Report Language
 PERT  Project Evaluation and Review Technique
 PGA   Pin Grid Array
 PHEMOSPHoto Emission MicrOScope
 PIQ   Polyimide
 PL    Product Line
 PLA   Programmable Logic Array
 PLBS  Product Line Business Strategy
 PLCC  Plastic Lead Chip Carrier
 PLD   Programmable Logic Device; Product Line Director
 PLL   Phased Locked Loop
 PLM   Product Line Manager
 PLP   Product Launch Plan
 PLPC  Product Line Production Control
 PLSM  Plasma Laboratory
 PM    Product Management; Preventative Maintenance
 PME   Product Marketing Engineer
 PMF   Product Master File
 PMM   Product Marketing Manager
 PMOS  P-channel Metal Oxide Silicon
 PMP   Product Migration Plan
 PMS   Product Marketing Status
 PO    Purchase Order
 POA   Potential Opportunity Analysis
 POD   Point Of Delivery
 POE   Pursuit Of Excellence
 POM   Product Of the Month
 POP   Process Oriented EPROM
 POS   Point Of Sales
 POTS  Plain Old Telephone Service
 PPA   Project Proposal Approval; Potential Problem Analysis
 PPBC  Preliminary Product Business Case
 PPDP  Preliminary Product Development Plan
 PPG   Programmable Products Group
 PPI   Plan Position Indicator
 PPM   Parts Per Million
 PPRS  Preliminary Product Requirements Specification
 PPS   Portable Personal Systems
 PPT   Personal Productivity Tools
 PQA   Product Quality Assurance Correlation request
 PQFP  Plastic Quad Flat Package
 PR    Publicity Release; Purchase Requisition; Public Relations
 PRL   Port Recreation Logic (pearl die)
 PROM  Programmable Read Only Memory
 PRS   Product Requirements Specification
 PS    Personal Systems; Product Strategy
 PSAD  Programmable Sense Amp Delay
 PSR   Photoresist Stripper Rinse
 PSW   Processor Status Word
 PTD   Period To Date
 PTG   Packaging Technology Group
 PU    Physical Unit
 PWM   Pulse Width Modulation
[Image]  Top

 QA    Quality Assurance
 QABB  Quality Bulletin Board
 QASD  Quality Assurance Systems Development
 QA & RQuality, Assurance and Reliability
 QBR   Quarter Business Review
 QBE   Query By Example
 QDR   Quantity Discrepancy claim Request
 QE    Quality Express
 QC    Quality Control
 QFD   Quality Function Deployment
 QFP   Quad Flat Pack
 QIP   Quality Improvement Plan
 QOS   Quality Operating System
 QP    Qual Plan
 QPL   Qualified Parts List
 QS    FACT Quiet Series
 QSA   Quality System Assessment
 QTD   Quarter To Date
 QTL   Q2 Test Language
 QTR   Quarter
 QUIC  QUality Information & Communications System
[Image]  Top

 R&A  Returns and Allowances
 R & DResearch and Development
 RAM  Random Access Memory
 RASP Retirement And Savings Plan
 RBC  Regional Business Center
 RBD  Regional Business Division
 REL  RELiability
 REV  REVision
 RF   Radio Frequency
 RFC  Request For Comments (Internet proposed standard doc)
 RFI  Radio Frequency Interference; Request For Information
 RFQ  Request For Quotation
 RFS  Request For Shipment
 RFSS Request For System Support
 RIC  Repeater Interface Controller
 RIE  Reactive Ion Etch
 RISC Reduced Instruction Set Computing
 RMA  Return Material Authorization
 RMC  Rack Mount Computer
 RMOS Reference Material Ordering System (x6684)
 RMP  Reliability Monitor Program
 ROCA Return On Controllable Assets (Mil-Aero)
 ROE  Return On Equity
 ROI  Return On Investment
 ROM  Read Only Memory
 RONA Return On Net Assets
 RSCS Remote Spooling Communications Subsystem
 RSM  Regional Sales Manager
 RSVP Reward Services and Value Provided
 RTS  Reliability Test Services
 RTC  Real Time Clock
 RTFDBRead the Flipping Data Book
 RUBY Random Unit BuYoff
[Image]  Top

 S      Schottky Logic
 SAC    Semiconductor Assembly Council
 SAG    Situation at A Glance
 SAM    Served Available Market
 SAMARI Sales And Marketing Analysis of Resales and Inventory
 SAS    Statistical Analysis Software
 SBE    Strategic Business Element
 SBEM   Strategic Business Element Manager
 SBI    Strategic Business Initiative
 SBP    Strategic Business Plan
 SBP1   Strategic Business Plan 1, the 5 yr. strategic plan
 SBP2   Strategic Business Plan 2, the 5 yr. financial/operations plan
 SBU    Strategic Business Unit
 SC     Santa Clara
 SCAN   Serial Control Access Network, NSC's boundary-scan family
 SCEM   Small Computer Expendability Module
 SCOPE  System Controllability, Observability, Partitioning Environment
 SCP    Single Chip Package
 SCSI   Small Computer Systems Interface
 SCVC   Santa Clara Valley Chapter
 SDK    Software Development Kit
 SDP    Standard Digital Products
 SDLC   Synchronous Data-Link Control
 SE     Sales Engineer
 SEA    South East Asia
 SEC    Securities and Exchange Commission
 SEM    Scanning Electronic Microscope
 SEMI   Semiconductor Equipment and Materials International
 SFAS   Statement of Financial Accounting Standards
 SGML   Standard Graphic Mark-up Language
 SIMM   Single In-line Memory Module
 SIMS   Secondary Ion Mass Spectrum
 SIO    Super I/O
 SIP    Single In-line Package
 SISO   Serial In Serial Out
 SLIC   Standard Linear Integrated Circuit
 SLIC   Subscriber Line Interface Circuit
 SLM    Single Layer Metal
 SLMC   Supply Line Management Center
 SMART  Sales & Marketing Analysis, Reporting & Tracking
 SMCC   Sun Microsystems Computer Corporation
 SMD    Surface Mounted Device
 SMM    Senior Marketing Manager; Strategic Marketing Manager
 SMS    Sales and Marketing Synergy; Semiconductor Material System
 SMS    Strategic Market Segment
 SMSC   SMS Steering Committee
 SMT    Surface Mount Technology
 SMTP   Simple Mail Transfer Protocol
 SNA    System Network Architecture (IBM term)
 SNI    Serial Network Interface
 SNIC   Serial Network Interface controller
 SNMP   Simple Network Management Protocol
 SO     Small Outline (package)
 SOG    Spin On Glass
 SOIC   Small Outline Integrated Circuit
 SOM    Share Of Market
 SONIC  System Oriented Network Interface Controller
 SOP    Standard Operating Procedure
 SPARC  Scalable Processor ARChitecture
 SP     System Product
 SPC    Statistical Process Control
 SPDT   Single Pole, Single Throw
 SPEC   SPECification
 SPG    Standard Products Group
 SQC    Statistical Quality Control
 SQL    Structured Query Language
 SRAM   Static Random Access Memory
 SRC    Signal Routing Card; Semiconductor Research Center
 SRD    Software Requirement Document;Spin Rinse Dryer
 SRP    Spreading Resistance Probe
 SRT    Source Routing Transparent
 STD    STanDard
 STI    STrategic Inventory
 STP    Shielded Twisted Pair
 SVG    Staggered Virtual Ground
 SVGA   SuperVGA
 SW     SoftWare
 SWISS  Semiconductor Worldwide Integrated Service System
[Image]  Top

 T&H    Temperature & Humidity (REL test)
 TA     Travel Authorization
 TA     Tel Aviv, NSC at Israel
 TAB    Tape Automated Bonding
 TAM    Total Available Market; Telecommunications Access Method
 TAS    Training Audit System
 TBA    To Be Announced
 TDB    To Be Determined
 TCP/IP Transmission Control Protocol/Internet Protocol
 TCV    Technology Characterization Vehicle
 TDDB   Time Dependent Dielectric Breakdown
 TE     Terminal Emulation; Test Engineer(ing)
 TEAM   Technology Evolution And Management
 TECN   Temporary ECN
 TEM    Transmission Electron Microscopy
 THBT   Temperature & Humidity Biased Test = T&H
 TJV    Transfer Journal Voucher
 TLA    Three Letter Acronym
 TLT    Team Leader Training
 TMCL   Temperature Cycle (REL test)
 TM     Trade Mark
 TMP    Terminal Management Processor
 T0     Time 0
 TP     Test Program
 TPX    Terminal Productivity eXtension
 TQ     Total Quality
 TQC    Total Quality Control
 TQM    Total Quality Manager

 TQRDCEBTechnology Quality Responsiveness Delivery Cost Environmental
        Awareness & Business Practice
 TRIC   Token Ring Interface Controller
 TROPIC Token Ring Protocol Interface Controller
 TPX    Terminal Productivity eXtension
 TSM    Target Segment Marketing; Target System Marketing
 TSO    Time Sharing Option

 TSR    Total Shareholder Return; Terminate and Stay Resident (software
        Program)
 TSS    Time Sharing System
 TTBE   Time To Break Even
 TTL    Transistor-Transistor Logic
 TVS    Triangular Voltage Sweep
[Image]  Top

 UARTUniversal Asynchronous Receiver-Transmitter
 uC  microController
 UDP User Datagram Protocol
 ULSIUltra LSI
 uP  microProcessor
 UPH Units Per Hour
 URD User Requirement Document
 URL Uniform Resource Locator
 USC UnderShoot Corrector (circuit for reducing undershoot)
 USG Undoped Silicon Glass
 UT  Ultra Tech
 UTP Untwisted Pair (wiring)
 UV  UltraViolet
[Image]  Top

 VAN  Vehicle Area Network
 VAR  Value-Added Reseller
 VAX  Virtual Address eXtension
 VBB  ECL Threshold Bias Voltage
 VCC  IC Power Supply Voltage (TTL)
 VDD  IC Power Supply Voltage (MOS)
 VEE  IC Power Voltage DC (ECL)
 VESA Video Equipment Standards Association
 VGA  Video Graphics Array
 VFPT Very Fine Pitch Technology ( < 15 mils)
 VHSICVery High Speed Integrated circuit
 VIH  Voltage Input High
 VIHD Dynamic VIH (IC Switching)
 VIL  Voltage Input Low
 VILD Dynamic VIL (IC Switching)
 VIP  Variable Incentive Program
 VLB  VESA Local Bus
 VLSI Very LSI
 VM   Virtual Machine
 VOH  Voltage Output High
 VOHP Quiet Output HIGH Noise Voltage, positive peak (overshoot)
 VOHV Output HIGH Noise Voltage, negative valley (VCC drop)
 VOL  Voltage Output Low
 VOLP Quiet Output LOW Noise Voltage, positive peak (ground bounce)
 VOLV Output LOW Noise Voltage, negative valley (undershoot)
 VOM  Vapox On Metal
 VP   Vice President
 VP/GMVice President & General Manager
 VPNP Vertical PNP
 VTR  Vertical Thermal Reactor
 VVC  Volume Variable Costs
[Image]  Top

 WAN     Wide Area Network
 WAW     Why Ask Why?
 WDS     Wavelength Dispersive Microscopy
 WINN    Working In the New National
 WIP     Work In Process
 WLR     Wafer Level Reliability
 WOF     Wall Of Fame
 WYSIWYG What You See Is What You Get
 WW      Work Week; World Wide
 WWW     WorldWideWeb

 XTALCrysTAL oscillator

 YTD Year To Date

 ZIFZero Insertion Force
 ZTT
    Zero Test Time



  [Multi monitor news]

Definition - Low Voltage Differential Signaling is a low noise, low
power, low amplitude method for high-speed (gigabits per second) data
transmission over copper wire.

LVDS differs from normal input/output (I/O ) in a few ways:

Normal digital I/O works with 5 volts as a high (binary 1) and 0 volts as
a low (binary 0). When you use a differential, you add a third option
(-5 volts), which provides an extra level with which to encode and
results in a higher maximum data transfer rate.

   A higher data transfer rate means fewer wires are required, as in UW
   (Ultra Wide) and UW-2/3 SCSI hard disks, which use only 68 wires. These
   devices require a high transfer rate over short distances. Using
   standard I/O transfer, SCSI hard drives would require a lot more than
   68 wires.

   Low voltage means that the standard 5 volts is replaced by either
   3.3 volts or 1.5 volts.

   LVDS uses a dual wire system, running 180 degrees of each other. This
   enables noise to travel at the same level, which in turn can get
   filtered more easily and effectively.

   With standard I/0 signaling, data storage is contingent upon the actual
   voltage level. Voltage level can be affected by wire length (longer
   wires increase resistance, which lowers voltage). But with LVDS,
   data storage is distinguished only by positive and negative voltage
   values, not the voltage level. Therefore, data can travel over greater
   lengths of wire while maintaining a clear and consistent data stream.
   Low Voltage Differential Signaling (LVDS) Technology: The Basics Low
   Voltage Differential Signaling (LVDS) technology is redefining data
   transmission at the physical layer interface. It is bringing high
   speeds and low power to this critical interface -- an essential step
   in meeting the high bandwidth requirements of tomorrow's networking,
   telecommunications and multimedia applications. This backgrounder
   answers the basic questions regarding LVDS technology: what is it,
   where is it used, why is it important and how does it work.

   What is LVDS?  LVDS is a new data interface standard that is defined
   in the TIA/EIA-644 and the IEEE 1596.3 standards. It is essentially
   a signaling method used for high-speed transmission of binary data
   over copper. It uses a lower voltage swing than other transmission
   standards. This low voltage differential is what delivers higher
   data transmission speeds and inherently greater bandwidth at lower
   power consumption.

   LVDS can achieve signaling rates as high as 655 megabits per second
   (Mbps). It consumes as little as one-eighth the power of RS-422
   drivers. Since the receivers respond only to differential voltages,
   they are relatively immune to noise such as common-mode signal
   reflections. In addition, LVDS emits less electromagnetic interference
   (EMI) than other data transmission standards.

   Where is LVDS used?  General purpose LVDS technology addresses
   point-to-point physical layer interfaces. These include intra-system
   connections via printed circuit board traces or cables. The ultimate
   rate and distance of LVDS data transfer is dependent on the attenuation
   characteristics of the media and the noise coupling to the environment.

   Applications for general purpose LVDS include central office, PBXs,
   switches, repeaters and basestations -- all in the telecommunications
   field. In addition, it is used in hubs and routers in data
   communications, and other applications such as digital cameras,
   printers and copiers.

   Outside the TIA/EIA 644 standard lies multipoint LVDS. Multipoint
   LVDS supports backplane applications such as proprietary buses and
   small computer system interface or SCSI. SCSI is a high-performance
   peripheral interface that distributes data independently of the
   host computer.  It's used with devices such as hard disk drives,
   tape drives, CD-ROMs and scanners.

   In addition to general purpose point-to-point applications and
   multipoint applications, LVDS has been used for several years as an
   interface to flat panel displays. As a result, it is used extensively
   in notebook computers.

   Why is LVDS important?  Physical layer interfaces are often a critical
   bottleneck in any application that requires high bandwidths, such as
   telecommunications and high-speed networking. For example, achieving
   higher data transmission on the backplane in a wireless basestation is
   critical to increasing the variety of services offered over wireless
   phones -- services such as full Internet capability, sending and
   receiving email and someday, even high-quality video.

   With its high speeds, low power and low cost profile, LVDS is today the
   most promising technology to address the physical layer interface. A
   direct comparison of LVDS to other data interface standards can
   be found in the accompanying fact sheet: "Profiles of Today's Data
   Transmission Standards."

   How does LVDS work?  In LVDS driver converts a TTL/CMOS signal into a
   low-voltage differential signal. This differential signal can travel
   at rates up to 655 Mbps over media such as copper cables or printed
   circuit board traces to the LVDS receiver. The receiver then translates
   the differential signal back into a TTL/CMOS signal.

   Using a differential signal reduces the system's susceptibility to
   noise and reduces EMI emissions -- in addition, to delivering high
   speeds. This results in a very cost-effective solution to some of
   the greatest bandwidth bottlenecks in many transmission applications.

   LVDS offers designers flexibility around their power supply solution,
   working equally well at 5V, 3.3V and lower. As a result, designers
   can reuse their LVDS solution even as systems move to lower voltages.

   Finally, LVDS has simple termination requirements -- usually one
   resistor at the inputs of the receiver compared to multiple resistor
   solutions for other standards.

   Texas Instruments and LVDS Texas Instruments (TI) introduced its first
   LVDS devices in 1996. Since then, the TI LVDS portfolio has grown
   to 17 devices -- making it one of the broadest in the industry. TI
   offers designers a variety of footprints, allowing them to choose
   the configuration that best fits their design application.

   In addition, TI's LVDS product line is fully supported with
   documentation and evaluation tools. TI offers a Data Transmission data
   book to help designers select the appropriate LVDS device. The LVDS
   Designers Guide offers advice for effectively implementing an LVDS
   solution. Application notes offer designers solutions to their design
   challenges. In addition, evaluation modules (EVMs) are available to
   help designers evaluate TI's LVDS products.

   TI is committed to LVDS technology and brings 30 years of leadership
   experience in data transmission to the LVDS market.

   Flat Panel Display Interface The Flat Panel Display Interface
   product family is composed of two classes of chipsets. The first is
   FPD-Link which provides a narrow high speed interface between graphic
   controllers on the motherboard and the TFT-LCD panel in Notebook
   applications. The second class is LDI (LVDS Display Interface) which
   is enhanced from FPD-Link by supporting long cable drive for flat panel
   desktop monitor applications. Each class of product is described below.

   LVDS Display Interface (LDI) The LDI chipset is a family of interface
   devices specifically configured to support data transmission from the
   graphics controller to LCD Panels in Desktop Monitor applications. To
   support long cable applications (>10m), an enhanced version of LVDS
   is employed. The enhancements include in the transmitters: selectable
   pre-emphasis and a simple low power DC Balancing scheme to open the eye
   pattern. The Receiver also offers a cable deskew function, that enables
   standard twisted pair cables to be used. LVDS delivers high speed,
   low power, low noise data transfer.  5.38Gbps of bandwidth is provided
   by the chipset at a 112MHz clock rate. With the use of MUX/DEMUX
   circuitry the overall size of the bus is reduced. This enables high
   resolution panels to be supported over a small cabled interface. The
   chipset supports SVGA, XGA, SXGA, UXGA, HDTV, and QXGA panels for
   high-resolution desktop displays and other image applications.


   Definition - Low Voltage Differential Signaling is a low noise,
   low power, low amplitude method for high-speed (gigabits per second)
   data transmission over copper wire.

   LVDS differs from normal input/output (I/O ) in a few ways:

   Normal digital I/O works with 5 volts as a high (binary 1) and 0
   volts as a low (binary 0). When you use a differential, you add a
   third option (-5 volts), which provides an extra level with which to
   encode and results in a higher maximum data transfer rate.

   A higher data transfer rate means fewer wires are required, as in UW
   (Ultra Wide) and UW-2/3 SCSI hard disks, which use only 68 wires. These
   devices require a high transfer rate over short distances. Using
   standard I/O transfer, SCSI hard drives would require a lot more than
   68 wires.

   Low voltage means that the standard 5 volts is replaced by either
   3.3 volts or 1.5 volts.

   LVDS uses a dual wire system, running 180 degrees of each other. This
   enables noise to travel at the same level, which in turn can get
   filtered more easily and effectively.

   With standard I/0 signaling, data storage is contingent upon the actual
   voltage level. Voltage level can be affected by wire length (longer
   wires increase resistance, which lowers voltage). But with LVDS,
   data storage is distinguished only by positive and negative voltage
   values, not the voltage level. Therefore, data can travel over greater
   lengths of wire while maintaining a clear and consistent data stream.
   Low Voltage Differential Signaling (LVDS) Technology: The Basics Low
   Voltage Differential Signaling (LVDS) technology is redefining data
   transmission at the physical layer interface. It is bringing high
   speeds and low power to this critical interface -- an essential step
   in meeting the high bandwidth requirements of tomorrow's networking,
   telecommunications and multimedia applications. This backgrounder
   answers the basic questions regarding LVDS technology: what is it,
   where is it used, why is it important and how does it work.

   What is LVDS?  LVDS is a new data interface standard that is defined
   in the TIA/EIA-644 and the IEEE 1596.3 standards. It is essentially
   a signaling method used for high-speed transmission of binary data
   over copper. It uses a lower voltage swing than other transmission
   standards. This low voltage differential is what delivers higher
   data transmission speeds and inherently greater bandwidth at lower
   power consumption.

   LVDS can achieve signaling rates as high as 655 megabits per second
   (Mbps). It consumes as little as one-eighth the power of RS-422
   drivers. Since the receivers respond only to differential voltages,
   they are relatively immune to noise such as common-mode signal
   reflections. In addition, LVDS emits less electromagnetic interference
   (EMI) than other data transmission standards.

   Where is LVDS used?  General purpose LVDS technology addresses
   point-to-point physical layer interfaces. These include intra-system
   connections via printed circuit board traces or cables. The ultimate
   rate and distance of LVDS data transfer is dependent on the attenuation
   characteristics of the media and the noise coupling to the environment.

   Applications for general purpose LVDS include central office, PBXs,
   switches, repeaters and basestations -- all in the telecommunications
   field. In addition, it is used in hubs and routers in data
   communications, and other applications such as digital cameras,
   printers and copiers.

   Outside the TIA/EIA 644 standard lies multipoint LVDS. Multipoint
   LVDS supports backplane applications such as proprietary buses and
   small computer system interface or SCSI. SCSI is a high-performance
   peripheral interface that distributes data independently of the
   host computer.  It's used with devices such as hard disk drives,
   tape drives, CD-ROMs and scanners.

   In addition to general purpose point-to-point applications and
   multipoint applications, LVDS has been used for several years as an
   interface to flat panel displays. As a result, it is used extensively
   in notebook computers.

   Why is LVDS important?  Physical layer interfaces are often a critical
   bottleneck in any application that requires high bandwidths, such as
   telecommunications and high-speed networking. For example, achieving
   higher data transmission on the backplane in a wireless basestation is
   critical to increasing the variety of services offered over wireless
   phones -- services such as full Internet capability, sending and
   receiving email and someday, even high-quality video.

   With its high speeds, low power and low cost profile, LVDS is today the
   most promising technology to address the physical layer interface. A
   direct comparison of LVDS to other data interface standards can
   be found in the accompanying fact sheet: "Profiles of Today's Data
   Transmission Standards."

   How does LVDS work?  In LVDS driver converts a TTL/CMOS signal into a
   low-voltage differential signal. This differential signal can travel
   at rates up to 655 Mbps over media such as copper cables or printed
   circuit board traces to the LVDS receiver. The receiver then translates
   the differential signal back into a TTL/CMOS signal.

   Using a differential signal reduces the system's susceptibility to
   noise and reduces EMI emissions -- in addition, to delivering high
   speeds. This results in a very cost-effective solution to some of
   the greatest bandwidth bottlenecks in many transmission applications.

   LVDS offers designers flexibility around their power supply solution,
   working equally well at 5V, 3.3V and lower. As a result, designers
   can reuse their LVDS solution even as systems move to lower voltages.

   Finally, LVDS has simple termination requirements -- usually one
   resistor at the inputs of the receiver compared to multiple resistor
   solutions for other standards.

   Texas Instruments and LVDS Texas Instruments (TI) introduced its first
   LVDS devices in 1996. Since then, the TI LVDS portfolio has grown
   to 17 devices -- making it one of the broadest in the industry. TI
   offers designers a variety of footprints, allowing them to choose
   the configuration that best fits their design application.

   In addition, TI's LVDS product line is fully supported with
   documentation and evaluation tools. TI offers a Data Transmission data
   book to help designers select the appropriate LVDS device. The LVDS
   Designers Guide offers advice for effectively implementing an LVDS
   solution. Application notes offer designers solutions to their design
   challenges. In addition, evaluation modules (EVMs) are available to
   help designers evaluate TI's LVDS products.

   TI is committed to LVDS technology and brings 30 years of leadership
   experience in data transmission to the LVDS market.

   Flat Panel Display Interface The Flat Panel Display Interface
   product family is composed of two classes of chipsets. The first is
   FPD-Link which provides a narrow high speed interface between graphic
   controllers on the motherboard and the TFT-LCD panel in Notebook
   applications. The second class is LDI (LVDS Display Interface) which
   is enhanced from FPD-Link by supporting long cable drive for flat panel
   desktop monitor applications. Each class of product is described below.

   LVDS Display Interface (LDI) The LDI chipset is a family of interface
   devices specifically configured to support data transmission from the
   graphics controller to LCD Panels in Desktop Monitor applications. To
   support long cable applications (>10m), an enhanced version of LVDS
   is employed. The enhancements include in the transmitters: selectable
   pre-emphasis and a simple low power DC Balancing scheme to open the eye
   pattern. The Receiver also offers a cable deskew function, that enables
   standard twisted pair cables to be used. LVDS delivers high speed,
   low power, low noise data transfer.  5.38Gbps of bandwidth is provided
   by the chipset at a 112MHz clock rate. With the use of MUX/DEMUX
   circuitry the overall size of the bus is reduced. This enables high
   resolution panels to be supported over a small cabled interface. The
   chipset supports SVGA, XGA, SXGA, UXGA, HDTV, and QXGA panels for
   high-resolution desktop displays and other image applications.