===========================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.