The Somewhat Complete Computer Glossary
Copyright 2001 by Joanne & Ron Vigneri
All Rights Reserved Rev: 12-28-07
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3D: Everybody knows what 3D is, but what is it in a computer? 3D is generally what is used to refer to the capabilities of the video card. Today's video cards use a variety of instructions built into the video card itself (not software) to achieve more realistic graphics in computer games that appear to have depth. Most of today's video cards have these capabilities, but there are incredibly large differences between specific cards. These 3D capabilities are generally used for games, but high-end video cards are used for creating 3D models and 3D animation. Many of the newer cards have a video RAM capacity of 64 MB.
3D Audio: Again, this is for gaming more than anything else. Sound cards such as the SoundBlaster series use techniques that make your speakers present sound that sounds like it is coming from behind or beside you instead of in front of you where your speakers are. The true effect is best with a set of four speakers.
3DNow!: AMD's set of additional instructions that they integrated into their CPUs. Similar to MMX and SSE/KNI, these instructions are intended to speed up CPU performance. These only appear in AMD CPUs.
A
Absolute cell address: A cell address in a spreadsheet that always refers to the same cell.
Access: The ability to open and read and work on files. Also, the name of a Microsoft database program.
Access arm: The disk drive mechanism used to position the read/write heads over the appropriate track.
Access time: The time interval between the instant a computer makes a request for a transfer of data from disk storage and the instant this operation is completed.
Accumulator: The computer register in which the result of an arithmetic or logic operation is formed (related to arithmetic and logic unit).
Active hub: A device used to amplify transmission signals in certain network topologies. An active hub can be used either to add additional workstations to a network or to lengthen the cable distance between workstations and the file server.
Active window: The window in Microsoft Windows with which the user may interact.
Add-on board: An optional circuit board that conveniently modifies or enhances a personal computer’s capabilities. (i.e. Memory board, Sound Card, Video Board, Network Interface Card.)
Address: (1) A name, numeral, or label that designates a particular location in RAM or disk storage. (2) A location identifier for nodes in a computer network.
Address bus: Pathway through which source and destination addresses are transmitted between RAM, cache memory, and the processor. (See also data bus)
ADSL (Asymmetric Digital Subscriber Line): A digital telecommunnications standard for data delivery over twisted-pair lines with downstream transmission speeds up to 9 M bps.
AGP: Accelerated Graphics Port is a high speed connection only used by video cards, so there is only one of them in a computer (older computers do not have AGP). It is faster than PCI and has direct access to system memory so that the computer's memory can be used in addition to the video card's memory. Default AGP speed is 66 MHz.
Algorithm: A standard method for computing something; essentially, a mathematical recipe.
Alpha: A reference to the letters of the alphabet. (Compare with numeric and alphanumeric.)
Alphanumeric: Pertaining to a character set that contains letters, digits, punctuation, and special symbols. (Related to alpha and numeric.)
America Online (AOL): An online information service.
Analog signal: A continuous waveform signal that can be used to represent such things as sound, temperature, and velocity. (See also digital signal.)
Animation: The rapid repositioning of objects on a display to create movement.
Anonymous FTP site: An Internet site that permits FTP (file transfer protocol) file transfers without prior permission.
ANSI: The American National Standards Institute is a nongovernment standards-settings organization that develops and publishes standards for “voluntary” use in the United States.
API (Application Programming Interface): A defined interface between an application and a software service module or operating system component. Conventionally, an API is defined as a subroutine library with a common definition set that extends across multiple computer platforms and operating systems.
Apache: An open source Web server that dominates the World Wide Web. There are more Apache servers running than all other Web server systems combined.
Applet: A small program sent over the Internet or an intranet that is interpreted and executed by Internet browser software.
Application generator: A system development tool used to actually generate the system programming code based on design specifications.
Application icon: A miniature visual representation of a software application oon a display.
Applications service provider (ASP): An ASP is a company that provides software-based services and solutions to customers via the Internet from a server computer.
Application window: A rectangular window containing an open, or running, application in Microsoft Windows.
Applications programmer: A programmer who translates analyst-prepared system and input/output specifications into programs. Programmers design the logic, then code, debug, test, and document the programs.
Applications software: Software designed and written to address a specific personal, business, or processing task.
Architecture: The particular selection, design, and interconnection of the main hardware and software components of a network.
Archive: To back up data files.
Argument: That portion of a function that identifies the data to be operated on.
Arithmetic and logic unit: That portion of the computer that performs arithmetic and logic operations. (Related to accumulator.)
Arithmetic operators: Mathematical operators (add (+), subtract (-), multiply (*), divide (/), and exponentiation (^) used in programming and in spreadsheet and database software for computations.
ARP (Address Resolution Protocol): The discovery protocol used by host computer systems to establish the correct mapping of Internet layer addresses, also known as IP addresses, to Media Access Control (MAC) layer addresses.
Artificial Intelligence (AI): The ability of a computer to reason, to learn, to strive for self-improvement, and to simulate human sensory capabilities.
AS (Autonomous System): The term used to describe a collection of networks administered by a common network-management organization. The most common use of this term is in interdomain routing, where an AS is used to descraibe a self-connected set of networks that share a common external policy with respect to connectivity, or in other words, networks that generally are operated within the same administrative domain.
ASIC (Application Specific Integrated Circuit): An integrated circuit that is an implementation of a specific software application or algorithm within a silicon engine.
ASII (American Standard Code for Information Inaterchange) : A 7-bit or 8-bit encoding system.
ASCII file: A generic text file that is stripped of program-specific control characters.
ASP (Active Server Pages): Microsoft’s proprietary architecture for developing NT-based dynamic Web server pages.
Assembler language: A programming language that uses easily recognized symbols, called mnemomics, to represent instructions.
Assistant system: This knowledge-based system that hellps users make relatively straightforward decisions. (See also expert system)
Asynchronous transmission: A protocol in which data are transmitted at irregular intervals on an as-needed basis. (See also synchronous transmission.)
ATA: See IDE.
AT/ATX: These are two standard types of motherboards, cases, and power supplies. An ATX motherboard generally must be used in an ATX case with an ATX power supply. When upgrading your computer, you need to know what type you have and what type you will be getting. If they're not compatible they won't work. ATX is becoming the norm, particularly for Pentium II, III, and Celeron computers. Retail computers like Gateway, Dell, Packard Bell, and Compaq often have their own proprietary standards. These often cause problems and prevent users from upgrading their motherboards and other components.
Attached file: A file that is attached and sent with an e-mail message.
Attribute: A field in a dimension table.
Audio file: A file that contains digitized sound.
Audio mail: An electronic mail capability that allows you to speak your message instead of typing it.
Authoring software: Software that lets you create multimedia applications that integrate sound, motion, text, animation, and images.
Automatic teller machine (ATM): An automated deposit/withdrawal device used in banking. {Back to TOP}
B
B-Channel: Refers to a single, full-duplex physical ISDN (Integrated Services Digital Network) interface that operates at 64 Kbps.
Bad block table: A list (kept on a hard disk) of storage on the disk that are physically unable to hold data reliably. The bad block table is usually duplicated on a label on the outside of the disk housing.
Backbone: A system of routers and the associated transmission media that facilitates the interconnection of computer networks.
Back-end applications software: This software on the server computer performs processing tasks in support of its clients, such as tasks associated with storage and maintenance of a centralized corporate database. (See also front-end applications software.)
Background: (1) That part of RAM that contains the lowest priority programs. (2) In Windows, the area of the display over which the foreground is superimposed. (Contrast with foreground)
Backup: Pertaining to equipment, procedures, or databases that can be used to restart the system in the event of system failure.
Backup file: Duplicate of an existing file.
Badge reader: An inpput device that reads data on badges and cards.
Bandwidth: Bandwidth refers to the quantity of data that can travel through your Internet connection per second, typically measured in bits. The greater the bandwidth of your connection, the more information you can send and receive per second.
Banner: A page of a printout that gives information about the file being printed. The banner page identifies the user who printed the file, the name of the file, the directory the file came from, the connection number of the workstation the file was printed from, and the date and time the file was printed. It is the first page printed.
Banner Ad: An advertisement placed on a Web page (often at top), which by convention is 60 pixels high and 468 pixels wide. Other shapes and forms of advertisements are also called banner ads.
Bar code: A graphic encoding technique in which printed vertical bars of varying widths are used to represent data.
Bar graph: A graph that contains bars that represent specified numeric values by their length.
Batch processing: A technique in which transactions and/or jobs are collected into groups (batched) and processed together.
Base I/O address: The beginning address of an I/O port. The base I/O address allows the microprocessor to find the correct port for communicating with a particular device.
Base Memory address: The beginning address of a block of memory. A network interface board uses the base memory address as a buffer where both the computer and the network interface board can leave information and signal the other to pick it up.
Baud: (1) A measure of the maximum number of electronic signals that can be transmitted via a communications channel. (2) Bits per second (common-use definition).
BECN (Backward Explicit Congestion Notification): A notification signal passed to the originator of traffic indicating that the path to the destination exceeds a threshold load level. This signal is defined explicitely in the Frame Relay frame header.
BGP (Border Gateway Protocol): An Internet routing protocol used to pass routing information between different administrative routing domains or AS (Autonomous Systems). The BGP routing protocol does not pass explicit topology information. Instead, it passes a summary of reachability between ASs. BGP is most commonly deployed as an inter-AS protocol.
Binary: A base-2 numbering system made up of a “0” bit and a “1” bit.
Bindery: A database maintained by the file server and used to monitor network resources. The bindery contains a list of “objects” (users, groups, file servers, etc.) and their “properties” (rights, passwords, network addresses, etc.)
BIOS: This is the Basic Input/Output System and is installed on the computer's motherboard. It controls the most basic operations and is responsible for starting your computer up and initializing the hardware. It is data that is usually held in a ROM chip, which can be updated by "flashing". BIOS upgrades may correct errors, support new CPUs, support new hardware, etc.
Bit: In a computer, all digital data is made up of bits and bytes. When computers talk or write to each other, they represent all of the information as “ones and zeros”, known as binary bits (1’s and 0’s) that comprise the binary code (based upon only two states, 1=ON and 0=OFF).
Bit-mapped graphics: Referring to an image that has been projected, or mapped, to a screen based on binary bits. (See also raster graphics)
BPS (Bits per Second): The standard measure of data transmission speeds.
Blocks: A unit of stored data.
BMP: A popular format for bit-mapped files.
Boilerplate: Existing text in a word processing file that can in some way be customized to be used in a variety of word processing applications.
Bold: A font presentation attribute that thickens the lines of a character.
Boot: The procedure for loading the operating system to RAM and readying a computer system for use.
Bootstrap (Bootstrap loader): A program that starts a “cold” computer. Generally, the bootstrap program tells the computer where to find the operating system software so that the computer can load the operating system.
Border router: Generally describes routers on the edge of an AS (Autonomous System). Uses BGP to exchange routing information with another administrative routing domain. However, this term also can describe any router that sits on the edge of a routing subarea, such as an OSPF (Open Shortest Path First) area border router.
BRI (Basic Rate Interface): A user interface to an ISDN (Integrated Services Digital Network) that consists of two 64-Kbps data channels (B-channels) and one 16-Kbps signaling channel (D-channel) sharing a common physical access circuit.
Bridge: A protocol-independent hardware device that permits communication between devices on separate local area networks.
Browsers: Programs that let you navigate to and view the various Internet resources.
Buffer: A storage area in RAM where data that is being transferred may be stored temporarily. Data is placed in buffers when the devices handling the data processes it at different rates. For example, a printer may not be able to process information as fast as a file server can send it. Any information the printer is receiving but cannot process immediately is placed in a buffer until the information can be processed.
Bug: A logic or syntax error in a program, a logic error in the design of a computer system, or a hardware fault. (See also debug)
Burner (CD-ROM): This is a device that allows you to save data to a CD-ROM. Special CD-Rs are required for this. They also allow you to make backup copies of your CDs. There is a large variety of types, including CD-R or CD-R/RW. The latter has support for rewritable CDs, which can be erased and rewritten to, while CD-R only drives can only write to their CDs once. Like CD-ROM drives, burners can be IDE or SCSI. SCSI is definitely preferable when it comes to burners, but a SCSI card is required. Burners are generally quite picky and must have a constant stream of data to work properly. If that stream is interrupted, the burn will fail. This is one reason why SCSI burners tend to be better; SCSI devices can deliver a more reliable stream of data than IDE while other applications are being run as well.
Burstable: The ability to use the full amount of bandwidth your connection can handle if needed at a given time. You usually get billed only on your average bandwidth use.
Bus, Data: The primary bus inside a personal computer, used for transferring data.
Bus, Network: The main network cable or line that connects network stations.
Bus or System Bus: This is just a collection of wires that transmit data from one component to another.
Bus Speed: This is a speed measured in MegaHertz that determines how fast the memory and CPU run. Some recent "official" bus speeds supported by Intel are 100 and 133 MHz. However, numerous others exist (75, 83, 103, 112, 124, 133, 153, etc.). High-quality memory is required for the higher bus speeds. The bus speeds usually determine the speed of the PCI and AGP buses as well. The default PCI bus speed is 33 and the default AGP bus speed is 66 MHz. The CPU speed is determined by a combination of the bus speed and multiplier (i.e. 100 bus speed x 4.5 multiplier = 450 MHz CPU speed).
Bus topology: A computer network form that permits the connection of terminals, peripheral devices, and microcomputers along a properly terminated central cable. There is a continuous progression in increasing bus speeds. (Coaxial cable typically)
Button bar: A software option that contains a group of pictographs that represent a menu option or a command.
Byte: A byte is typically eight bits that represent a character in binary code. (See “bit” above) {Back to TOP}
C
C: A transportable programming language that can be used to develop software.
C++ : An object-oriented version of the C programming language.
Cache: It's said just like cash, but has an entirely different meaning. Cache memory is the fastest type of RAM available and is used in CPUs, hard drives, and a variety of other components. As with RAM, the more cache, the better, but CPU and hard drive cache generally cannot be upgraded. Pentium II CPUs have 512 KiloBytes of cache, and the high-end IBM 9LZX SCSI hard drives have a large 4 MegaBytes cache. Like RAM, data generally passes through cache memory before going to the component that is going to use it (the CPU). It holds the data for quick access as well. The speed of the cache is also very important. Pentium II CPUs have 512 k cache, and Celeron CPUs have 128 k of cache, but the Celeron cache runs at full CPU speed while the Pentium II's cache runs at 1/2 CPU speed. Thus, there is a tradeoff that makes the Celeron run about as fast as the Pentium II CPU. There is a continuous progression toward increased cache levels.
Cache memory: High-speed solid-state memory for program instructions and data.
Carrier: Standard-fixed pin connectors that permit chips to be attached to a circuit board.
Cascading menu: A pop-up menu that is displayed when a command from the active menu is chosed.
Cascading windows: Two or more windows that are displayed on a computer screen in an overlapping manner.
Case: The computer's case is nothing more than its shell or a skeleton. The case performs the function of holding the computer together, cooling (with fans), and grounding the computer components through its steel. Larger cases with a lot of expansion bays are preferable. This way you can have a lot of room to work in your case and be able to upgrade with more hard drives, DVD drives, burners, etc. SuperMicro's SC750-A server tower is an example of a great case. It has a total of 8 external bays, plenty of room to work, and a great cooling setup with space for a lot of fans. Tower cases are generally preferred over desktop cases because they have more room for expansion and better cooling capabilities. A case can be AT or ATX, differing in the way the holes are laid out to connect the motherboard to and the type of power supply if it comes with one. Cases generally come with power supplies, but it is often advisable to get them separately so that you can get high quality parts for both.
CBQ (Class Based Queuing): A queuing method by which traffic is classified into separate classes and queued according to its assigned class in an effort to provide differential forwarding behavior for certain types of network traffic.
CD production station: A device used to duplicate locally produced CD-ROMs.
CD-ROM Burner: See Burner.
CD-ROM Drive: A storage device into which an interchangeable CD-ROM is inserted for processing.
CD writer: A peripheral device that can write once to a CD-R or CD-RW disk to create an audio CD or a CD-ROM.
CD-R (Compact Disc-Recordable): The medium on which CD writers create CDs and CD-ROMs.
CD-Rewritable (CD-RW): This technology allows users to rewrite to the same CD media.
CD-ROM disk (Compact-Disk Read-Only Memory disk): A type of optica laser storage media.
Celeron: A line of Intel microprocessors designed for low-cost PCs.
Cell: The intersection of a particular row and column in a spreadsheet.
Cell address: The location (column and row) of a cell in a spreadsheet.
Central processing unit (CPU): See processor.
Centronics connector: A 36-pin connector that is used for the electronic interconnection of computers, modems, and other peripheral devices.
CGM: A popular vector graphics file format.
Channel: The facility by which data are transmitted between locations in a computer network (e.g., terminal to host, host to printer).
Channel capacity: The number of bits that can be transmitted over a communications channel per second.
CHAP (Challenge Handshake Authentication Protocol): An authentication mechanism for PPP (Point-to-Point Protocol) connections that encrypts the user password.
Character: A unit of information that is usually composed of six, seven, or eight bits. Also, a figure that is a unit of information, such as an “E”.
Character set: The group of characters a computer can recognize and process. PC-compatible computers use an extended ASCII character set which extends from decimal 0 to 255.
Chief Information Officer (CIO): The individual responsible for all the informatiooon services activity in a company.
Chips/Chipsets: These are the little pieces of silicon that hold computer information and instructions. Just about any computer component has at least one chipset on it. Motherboard chipsets control the basic input/output of the computer. Video card chipsets control the rendering of 3D graphics and the output of images to your monitor. The CPU is just a very important chip. Common motherboard chipsets include the BX, i810, i820, and many others.
Choose: To pick a menu item or icon in such a manner as to initiate processing activity.
CIR (Committed Information Rate): A Frame Relay term describing a minimum access rate at which the service provider commits to provide the customer for any given Permanent Virtual Circuit (PVC).
CISC (Complex Instruction Set Computer): A computer design architecture that offers machine language programmers a wide variety of instructions. (Contrast with RISC.)
Click: A single tap on a mouse’s button. (Switch contact)
Client application: (1) An application running on a networked workstation or PC that works in tandem with a server application. (See also server application.) (2) An object linking and embedding the application containing the destination document.
Client Computer: Typically a PC or a workstation that requests processing support or another type of service from one or more server computers. (See also server computer)
Client program: A software program that runs on a PC and works in conjunction with a companion server program that runs on a server computer. (See also server program)
Clients and Servers: Servers, or host computers, “serve” data (ranging from simple text files to software) to a client.
Clip art: Prepackaged electronic images that are stored on disk to be used as needed in computer-based documents.
Clipboard: An intermediate holding area in internal storage for information en route to another application.Allows transfers of Screen Shots when used with Print Screen key on the keyboard.
Clone: A hardware device or a software package that emulates a product with an established reputation and market acceptance.
Cluster: The smallest unit of disk space that can be allocated to a file.
CMOS RAM: Random access memory for storing system configuration data (number of drives, type of drives, amount ;of memory, etc.). The CMOS RAM is battery operated and is not available to the computer’s operating system. (Part of the BIOS system)
Coaxial cable: A shielded wire used as a medium to transmit data between computers and between computers and peripheral devices. Type RG-58 used in Ethernet 10Base 2 network wiring.
COBOL (Common Business Oriented Language): A third-generation programming language designed to handle business problems.
Code: (1) The rules used to translate a bit configuration into alphanumeric characters and symbols. (2) The process of compiling computer instructions into the form of a computer program. (3) The actual computer program.
Cold Boot: To reload a computer’s operating system by turning the computer’s power off and then back on. (If a computer has a reset switch, a cold boot can be performed without turning the power off and on.)
Color Depth: Refers to the number of colors displayed to the monitor by the video card. The more colors used, the more realistic the display. With photographs, changing the computer's color depth may or may not help if the picture is limited to a small amount of colors. Common color depths are 256 colors, 16-bit (65,000 colors), 24-bit, and 32-bit (millions of colors). 24-bit and 32-bit are difficult to differentiate between, but 16-bit and particularly 256 colors will show a noticeable lack of quality or realism.
Command: An instruction to a computer that invokes the execution of a preprogrammed sequence of instructions.
Common carrier: A company that provides channels for data transmission. (ILEC, CLEC types of telephone local exchange carriers)
Communication buffers: Areas in the memory of a file server or bridge that are set aside to temporarily hold packets arriving from the various network stations until the file server or bridge is ready to process them and send them to their destination. Also called “routing buffers.”
Communications channel: The facility by which data are transmitted between locations in a computer network.
Communication medium: The physical device that carries a signal (data) from one place to another. A communication medium may be wiring (such as coaxial cable, twisted-pair cable, or dual-twisted-pair cable), or it may be a non-wire medium such as fiber optics, infrared, or microwave.
Communications protocols: Rules established to govern the way data in a computer network are transmitted.
Communications server: The LAN component that provides external communications links.
Communications software: (1) Software that enables a microcomputer to emulate a terminal and to transfer files between one computer and another computer. (2) Software that enables communication between remote devices in a computer network.
Compact disc-recordable: See CD-R and CD-RW.
Compatibility: Pertaining to the ability of computers and computer components (hardware and software) to work together.
Compile: To translate a high-level programming language into machine language in preparation for execution.
Compiler: A program that translates the instructions of a high-level language to machine language instructions that the computer can interpret and execute.
Compound document: A document, such as a word processing document, that contains one or more linked objects from other applications.
CompuServe: An online information service.
Computer: An electronic device capable of interpreting and executing programmed commands for input, output, computational, and logical operations.
Computer competency: A fundamental understanding of the technology, operation, applications, and issues surrounding computers.
Computer matching: The procedure whereby separate databases are examined and individuals common to both are identified.
Computer monitoring: Observing and regulating employee activities and job performance through the use of computers.
Computer network: An integration of computer systems, terminals, and communications links.
Computer operator: One who performs those hardware-based activities needed to keep production information systems operational in the computer environment.
Computer system: A collective reference to all interconnected computing hardware, including processors, storage devices, input/output devices, and communications equipment.
Computer virus: See virus.
Computer-aided design (CAD): Use of computer graphics in design, drafting, and documentation in product and manufacturing engineering.
Computer-aided software engineering (CASE): An approach to software development that combines automation and the rigors of the engineering discipline.
Computer-based training (CBT): Using computer technologies for training and education.
Computerese: A colloquial reference to the language of computers and information technology.
Configuration: The computer and its peripheral devices.
Configuration hardware: (1) The equipment used on a network (file servers, workstations, printers, cables, network interface boards, bridges, hubs, routers, etc.), and the way it is connected—the physical layout of a network. (2) The specific type of hardware installed in or attached to the computer itself, such as disk subsystems, network interface boards, memory boards, printer boards, etc. (3) A specific set of parameters selected for an electronic computer board or adapter.
Configuration software: The procedure that prepares software programs to run on the computer’s specific hardware, operating system, memory capacity, peripherals, etc.
Connection number: A number assigned to any workstation that logs in to a file server; It may be a different number each time that a workstation logs in. The file server’s operating system uses connection numbers to control each stations communication with other stations.
Connectivity: Pertains to the degree to which hardware devices, software, and databases can be functionally linked to one another.
Console: The monitor and keyboard from which you actually monitor and control computer (standalone, client, or server) activity and operation.
Context-sensitive: Referring to an on-screen explanation that relates to a user’s current software activity.
Controller address: The number that is physically set (usually with jumpers) on a hard disk controller board, and which is used by the operating system to locate the controller on a disk channel.
Controller board: A device that enables a computer to communicate with a particular device (disk, network interface card, tape drive, etc.). The controller board manages input/output and regulates the operation of its associated device.
Control unit: The portion of the processor that interprets program instructions, directs internal operations, and directs the flow of input/output to or from RAM.
Cookie: A message given to the user’s Web browser by the Web server being accessed. The cookie is a text file containing user preference information.
Cooperative processing: An environment in which organizations cooperate internally and externally to take full advantage of available information and to obtain meaningful, accurate, and timely information. (See also intercompany networking.)
CoS (Class of Service): A categorical method of classifying traffic into separate classes to provide differentiated service to each class within the network.
CPE (Customer Premise Equipment): The equipment deployed on the customer’s site when the customer subscribes (or simply connects) to a carrier’s access service.
CPU: The CPU is the computer's control center. Think of it as the brain that does all the thinking (computation), thus it is called the Central Processing Unit. The actual CPU is about 1.5 inches square, yet it is the most critical part of the computer. Having a fast CPU (measured in MegaHertz) greatly aids in the overall speed of your computer. Visit my CPU Page.
Cracker: An overzealous hacker who “cracks” through network security to gain unauthorized access to the network. (Also see hacker)
Crash: A slang term that means hardware or software has stopped working properly.
Cross-platform technologies: Enabling technologies that allow communication and the sharing of resources between different platforms.
CRT (Cathode-Ray Tube): The video monitor component of a terminal.
Cryptography: A communications crime-prevention technology that uses methods of data encryption and decryption that securely scramble codes sent over communications channels.
CSMA/CD access method (Carrier Sense Multiple Access/Collision Detection): A network access method in which nodes on the LAN must contend for the right to send a message. Senses data packet collisions, if none, then allows any node access to send data.
CSU/DSU (Channel Service Unit/Data Service Unit): A Customer Premise Equipment (CPE) device that provides the telephony interface for circuit data services, including the physical framing, clocking, and channelization of the circuit.
Current drive: Distinct, concentric storage areas on a hard disk (roughly corresponding to tracks on a floppy diskette). Generally, the more cylinders a hard disk has, the greater its storage capacity. (See also Default Drive)
Current Window: The window in a GUI in which the user can manipulate text, data, or graphics.
Cursor, graphics: Typically an arrow or a cross hair that can be moved about a monitor’s sceen by a point-and-draw device to create a graphic impage or select an item from a menu.
Cursor, text: A blinking character that indicates the location of the next keyed-in character on the display screen.
Cursor-control keys: The arrow keys on the keyboard that move the cursor vertically and horizontally.
Custom programming: Program development to create software for situations unique to a particular processing environment.
Cyberphobia: The irrational fear of, and aversion to, computers.
Cylinder: A disk-storage concept. A cylinder is that portion of the disk that can be read in any given position of the access arm. (Contrast with sector.)
D-Channel (Data Channel): A full-duplex control and signaling channel on an ISDN BRI (Basic Rate Interface) or PRI (Primary Rate Interface). The D-Channel is 16 Kbps on an ISDN BRI and 64 Kbps on a PRI.
Data: Representations of facts. The raw material of information. (Plural of datum.)
Database: On a network, a collection of data (fields and tables) organized and stored on disk by network users, usually through use of a special application program.
Data bits: A data communications parameter that refers to a timing unit or packet structure.
Data bus: A common pathway between RAM, cache memory, and the processor through which data and instructions are transferred. (See also address bus)
Data cartridge: Magnetic tape storage now usually in a cassette format.
Data communications: The collection and distribution of the electronic representation of information between two locations.
Data compression: A method of reducing disk-storage requirements for computer files.
Data entry: The transcription of source data into a machine-readable format.
Data file: This file contains data organized into records.
Data flow diagram: A design technique that permits documentation of a system or program at several levels of structure.
Data mining: An analytical technique that involves the analysis of large databases, such as data warehouses, to identify possible trends and problems.
Data path: The electronic channel through which data flows within a computer system.
Data processing (DP): Using the computer to perform operations on data.
Data processing (DP) system: Systems concerned with transaction handling and record keeping, usually for a particular functional area.
Data transfer rate: The rate at which data are read/written from/to disk storage to RAM or a device or other data path like a network cable.
Data/voice/fax/modem: A modem that permits data communication with remote computers via a telephone line link and enabling telephone calls and fax machine simulation via a PC.
Data warehouse: An approach to database management that involves moving existing operational files and databases from multiple applications to a data warehouse.
Database: The integrated data resource for a computer-based information system.
Database administrator (DBA): The individual responsible for the physical and logical maintenance of a database.
Database software: Software that permits users to create and maintain a database and to extract information from the database.
DCE (Data Communications Equipment): A device on the network side of a User-to-Network Interface (UNI). Typically, this is the Customer Premise Equipment (CPE), such as a modem or Channel Service Unit/Data Service Unit (CSU/DSU).
DDR: This is a new type of RAM called Double Data Rate RAM. It is used in some of the newer video cards such as the Nvidia GeForce cards.
DE (Discard Eligible): A bit field defined within the Frame Relay header indicating that a frame can be discarded within the Frame Relay switch when the local queuing load exceeds a configured threshold.
Debug: To eliminate bugs in a program or system. (See also bug.)
Decision support system (DSS): An interactive information system that relies on an integrated set of user-friendly hardware and software tools to produce and present information targeted to support management in the decision-making process. (Contrast with management information system and executive information system.)
Decode: To reverse the encoding process. (Contrast with encode)
Decoder: That portion of a processor’s control unit that interprets instructions.
Dedicated keyboard port: A port built into the system board specifically for the keyboard.
Dedicated mouse port: A port built into the system board specifically for the cursor-control device.
Default: A value or option that is chosen automatically when no other value is specified. For example, if a word processing program has a preset page length, it is called the “default” page length.
Default drive: The drive that a workstation is currently using. The drive prompt (A, C, etc.) identifies the default drive letter.
Default options: Preset software options that are assumed valid unless specified otherwise by the user.
Default server: The file to which your default drive is mapped. In other words, the drive you are currently using is mapped to a particular file server; therefore, that file server is your default server. Any commands you enter will be directed automatically to the default server unless you specify otherwise.
Defragmentation: Using utility software to reorganize files on a hard disk such that files are stored in contiguous clusters.
Delimiter: A symbol or character that signals the beginning or end of a command or parameter within a command. For example, in the command CHKVOLA: B:, the blank space between A: and B: is a delimiter that marks two distinct parameters. Other delimiters include the comma (,), the period (.), the slash (/), and the colon (:).
Density: The number of bytes (or bits, pixels, dots, etc.) per linear length or unit area of a recording medium.
Desktop: The screen in Windows upon which icons, windows, a background, and so on are displayed.
Desktop PC: A nonportable personal computer that is designed to rest on the top of a desk. (Contrast with laptop PC and tower PC forms)
Desktop publishing software (DTP): Software that allows users to produce near-typeset-quality copy for newsletters, advertisements, and many other printing needs, all from the confines of a microcomputer.
Destination: The computer or network station, directory, drive, printer, etc., to which data is sent.
Destination application, clipboard: The software application into which the clipboard contents are to be pasted. (Contrast with source application)
Detailed system design: That portion of the systems development process in which the target system is defined in detail.
Device controller: Microprocessors that control the operation of peripheral devices.
Device driver software: Software that contains instructions needed by the operating system to communicate with the peripheral device.
DHCP (Dynamic Host Configuration Protocol): A protocol that is used on server or end-system computers to automatically obtain an IP (Internet Protocol) host address, subnet mask, and local gateway information. A DHCP server dynamically supplies this information in response to workstation (client) or end-system broadcast requests.
Diagnostic: A procedure used to detect and isolate a malfunction or mistake.
Dialog box: A window that is displayed when the user must choose parameters or enter further information before the chosen menu option can be executed.
Dial-up connection: Temporary modem-based communications link with another computer.
Dial-up: A dial-up Internet account allows you to use a computer with a modem and appropriate software to connect to the Internet through an Internet Service Provider (ISP). The software “dials” the ISP’s access numbers and you can then send e-mail, browse the World Wide Web or engage in other Internet activities.
Digital: A reference to any system based on discrete data, such as the binary nature of computers.
Digital Camera: This is a camera that does not use film, but instead stores the photographs in a digital format in memory on the camera. These images can then be downloaded to a computer.
Digital convergence: The integration of computers, communications, and consumer electronics, with all being digitally compatible.
Digital ID: A digital code that can be attached to an electronic message that uniquely identifies the sender.
Digital signal: Electronic signals that are transmitted as in strings of 1s and 0s. (See also analog signal)
Digital video disk (DVD): The successor technology to the CD-ROM that can store up to 10 gigabytes.
Digitize: To translate data or an image into a discrete digital format that can be interpreted by computers.
Digitizer tablet and pen: A pressure-sensitive tablet with the same x-y coordinates as a computer-generated screen. The outline of an image drawn on a tablet with a stylus (pen) or puck is reproduced on the display.
DIMM (Dual In-line Memory Module): A small circuit board, capable of holding several memory chips, that has a 64-bit data path and can be easily connected to a pC’s system board. (Contrast with SIMM)
Dimmed: A menu option, whish is usually gray, that is disabled or unavailable.
Direct conversion: An approach to system conversion whereby operational support by the new system is begun when the existing system is terminated.
Direct-access storage device (DASD): A random-access disk storage device.
Direct memory access (DMA): A technology that may increase file server speed. The file server processor passes parameters to a special integrated circuit (chip) that controls the reading and writing of memory, independent of the file server processor. This enables the file server processor to perform other tasks. (Most Intel x86-based machines, perform better when DMA is not used.)
Directory: (1) A logical portion of disk space that is named. The user creates directories (folders) and assigns them names. A directory may be part of another directory, and may contain several other directories. The different “levels” of directories on any disk form a hierarchical “directory structure”. Directories contain files, grouping them together conveniently. (2) The list of files that are contained in a directory. This list is displayed when the DOS directory command DIR is issued at any directory level.
Directory caching: A method of decreasing the time it takes to determine a files’ location on a disk. The file allocation table and directory entry are written into the file servers’ memory. A files’ location can then be read from memory, which is much faster that reading from the disk.
Directory name: A name that both identifies a directory and reflects its position within a directory structure. On a network, the full directory name lists the name of the file server, the volume, and each subdirectory leading down to the directory you need to access. The directory name is also called the directory path.
Directory path: See Directory Name.
Directory server: A data warehouse that keeps track of all the users of a system as well as all the resources available on the system, such as database servers, file servers, printers, and communications resources.
Directory structure: the different levels of directories (parent directories, subdirectories, etc.) organized to form a hierarchy. (See also Directory Name)
Directory table (hard disk): A table (kept on a hard disk) that contains information about each file and directory, such as the name, creation date, size, date and time of each update, file attributes, trustees, etc.
Disable: (1) To turn off, to render inactive. For example, the console command DISABLE LOGIN prevents workstations from logging in to the file server. (2) To prevent certain interrupts from occurring in a processing unit (such as a network interface board) by setting a switch or a jumper, or through some other means.
Disk: A magnetically encoded storage medium in the form of a plate (also called a platter). Disks used with personal computers are usually divided into two types: hard and floppy. Hard disks use a metallic base and usually are fixed within a computer or installable unit (they may be removable). Floppy disks (called diskettes) use a polyester base and are always removable. Can also refer to the device that physically transfers data to and from a disk.
Disk address: The physical location of a particular set of data or a program on a magnetic disk.
Disk caching: A hardware/software technique in which frequently referenced disk-based data are placed in an area or RAM that simulates disk storage.
Disk controller: A controller board that regulates the operation of a disk drive.
Disk coprocessor board (DCB): An intelligent board that acts as an interface between the host microprocessor and the disk controller. The Disk Coprocessor board relieves the host microprocessor of data storage and retrieval tasks, thus increasing the computers’ performance time. A disk Coprocessor board and its disk subsystems make up a disk channel.
Disk density: The number of bits that can be stored per unit of area on the disk-face surface.
Disk drive: A device that can write to a disk (store data) and read from a disk (retrieve data). A disk drive can be internal (built into the computer) or external (attached as a peripheral to the computer). The disk controller regulates the disk drives’ operation.
Disk duplexing: A method of safeguarding data in which the same data is copied simultaneously to two hard disks on separate channels. Also known as “disk mirroring” or “disk striping” in certain methods. If one channel fails, the data on the other channel remains unharmed. When data is duplexed, read requests are sent to whichever disk in the pair that can respond faster, thus increasing the file servers’ efficiency. When two or more read requests occur together, the requests are split and can be processed at once.
Disk interface board: An add-on board that acts as an interface between the host microprocessor and the disk controller.
Disk drive, magnetic: A magnetic storage device that records data on flat rotating disks. (Compare with tape drive, magnetic)
Disk, magnetic: A storage medium for random-access data storage available in permanently installed or interchangeable formats.
Disk optimizer: A program that reorganizes files on a hard disk to eliminate file fragmentation.
Disk subsystem: An external unit that attaches to the file server and may contain hard disk drives, a tape drive, or both. The disk subsystem gives the file server more storage capacity. A disk channel can accommodate up to eight disk subsystems.
Diskette: A thin interchangeable disk for secondary random-access data storage (same as floppy disk).
DLCI (Data Link Connection Identifier): A numerical identifier given to the local end of a Frame Relay Virtual Circuit (VC). The local nature of the DLCI is that it spans only the distance between the first-hop Frame-Relay switch and the router, whereas a VC spans the entire distance of an end-to-end connection between two routers that use the Frame Relay network for link-layer connectivity.
DLSw (Data Link Switching): Provides a standards-based method for forwarding SNA (Systems Network Architecture) traffic over TCP/IP (Transmission Control Protocol/Internet Protocol) networks using encapsulation. DLSw provides enhancements to traditional RSRB (Remote Source-Route Bridging) encapsulation by eliminating hop-count limitation, removes unnecessary broadcasts and acknowledgements, and provides flow-control.
DNS (Domain Name Server): Connected to the Internet, they translate the letters in Internet addresses into numerical designations. Why? Because it’s easier for most of us to remember http://www.getwireless.net/ than the corresponding IP address, 199.234.153.10.
Docking station: A device into which a notebook PC is inserted to give the notebook PC expanded capabilities, such as a high-capacity disk, interchangeable disk options, a tape backup unit, a large monitor, and so on.
Document: A generic reference to whatever is currently displayed in a software package’s work area or to a permanent file containing document contents.
Document file: The result when work with an applications program, such as word processing, is saved to disk storage.
Document icon: A pictograph used by Windows within an application to represent a minimized document window.
Document window: Window within an application window that is used to display a separate document created or used by that application.
Domain Name: The unique name of a computer connected to the Internet. In the address, sales@getwireless.net, Getwireless is the domain name and the extension “net” (the domain indicates that Getwireless.net is a network. “sales” is a mailbox. In addition to “net,” other top-level domains are “com” (commercial ventures), “org” (ususally a non-profit organization), “edu” (educational institutions), “gov” (governments) and “mil” (military).
DOS (Disk Operating System): An operating system for individual personal computers that is stored on disk. (See also Operating System)
Dot pitch: The distance between the centers of adjacent pixels on a display.
Dot-matrix printer: A printer that arranges printed dots to form characters and images.
Double-click: Tapping a button on a point-and-draw device twice in rapid succession.
Download: The transmission of data from a remote computer to a local computer.
Downstream rate: The data communications rate from server computer to client computer.
Downtime: The time during which a computer system is not operational.
DPI ( Dots per Inch): Measurement used both on monitors and printers. The measurements are done different ways though. The higher numbers on printers generally represent more detailed print quality (i.e. 1200x1200) would be very high resolution printing). The lower numbers on monitors represent clearer picture quality (i.e. .22 dpi would be a very high quality monitor).
Drag: A point-and-draw device procedure by which an object is moved or a contiguous area on the display is marked for processing.
Drive: A device that reads information from a disk or tape. The term may refer to the actual hardware that reads the information (physical drive), or it may be used as an abstract identification for a storage location (logical drive). A local drive is physically attached to the workstation; a network drive reads information from a specific directory on the network, rather than from a local disk.
Driver: The software that enables interaction between the operating system and a specific peripheral device.
Drive letter: A letter that represents a local drive or logical drive.
Driver module: The program module that calls other subordinate program modules to be executed as they are needed (also see main program).
DS0 (Digital Signal Level 0): A circuit-framing specification for transmitting digital signals over a single channel at 64 Kbps on a T1 facility.
DS1 (Digital Signal Level 1): A circuit-framing specification for transmitting digital signals at 1.544 Mbps on a T1 facility in the United States, or at 2.108 Mbps on an E1 facility elsewhere.
DS3 (Digital Signal Level 3) A circuit-framing specification for transmitting digital signals at 44.736 Mbps on a T3 facility.
DSBM (Designated Subnet Bandwidth Manager): A device on a managed subnetwork that acts as the Subnet Bandwidth Manager (SBM) for subnetwork to which it is attached. This is done through a complicated election process specified in the SBM protocol specification. The SBM protocol is a proposal in the IETF (Internet Engineering Task Force) for handling resource reservations on shared and switched IEEE (The Institute of Electrical and Electronics Engineers) 802 style local area media.
DSL (Digital Subscriber Line): Similar to a cable modem but uses phone lines.
DTE (Data Terminal Equipment): A device on the user side of a User-to-Network Interface (UNI). Typically, this is a computer or a router.
DVD-ROM Drive: Similar to a CD-ROM drive, a DVD Drive reads CDs, CD-ROMs, and the newer DVDs. The acronym DVD originally had no meaning, but has since been referred to as Digital Video Disk and Digital Versatile Disk. DVD's advantage over CDs is that it holds many times the capacity of a single CD. DVDs can also hold full-length movies and can be used double-sided for extra storage. Currently very few software titles are available only on DVD-ROM, but are also available on CD-ROM, usually requiring multiple CDs. DVD videos are only available on DVD though. DVD also requires and MPEG decoder card to view the Videos. Software DVD decoding can be done on very fast machines, but hardware decoding (simply meaning a piece of hardware is added to the computer along with the drive - a decoder card) will work much better.
Dynamic Memory: A form of memory that requires a continual rewriting of all stored information. A continuous electrical current is necessary to maintain dynamic memory. A common example is dynamic RAM: all data is lost when the power supply is turned off.
E1: A WAN (Wide-Area Network) transmission circuit that carries data at a rate of 2.048 Mbps. Predominantly used outside the United States.
E3: A WAN transmission circuit that carries data at a rate of 34.368 Mbps. Predominantly used outside he United States.
EBCDIC (Extended Binary Coded Decimal Interchange Code): An 8-bit encoding system.
Echo: A host computer’s retransmission of characters back to the sending device.
E-commerce (electronic commerce): Business conducted online, primarily over the Internet.
Edge device: Any device on the edge or periphery of an administrative boundary.
Electronic data interchange (EDI): The use of computers and data communications to transmit data electronically between companies.
Embedded SCSI: A hard disk that uses a SCSI interface and has a controller board built into the hard disk unit.
Emulation: On a network, the imitation of all or part of one device by another so that the mimicking device can accept the same data and perform the same functions as the actual device.
Enable: (1) To turn on, especially to restore a feature that has been disabled. For example, the console command ENABLE LOGIN allows workstations to log in to the file server after they have been prevented from doing so. (2) To place in a state that will allow certain interrupts to occur in a processing unit (such as a network interface board). Interrupts are usually enabled by setting a switch or a jumper.
Encode: To apply the rules of a code. (Contrast with decode.)
Encoding system: A system that permits alpha-numeric characters and symbols to be coded in terms of bits.
End-system: Any device that terminates an end-to-end communications relationship
EPS (Encapsulated PostScript): A vector graphics file format used by the PostScript language.
ESDI : Enhanced Small Device Interface
Ethernet: A transport method (protocol) used to connect computers to a LAN (Local Area Network) and exchange data.
Executable program file: A file that contains programs that can be executed and run on a computer.
Execution time (E-time): The elapsed time it takes to execute a computer instruction and store the results.
Exit routine: A software procedure that returns you to a GUI, an operating system prompt, or a higher-level applications program.
Expansion board: These add-on circuit boards contain the electronic circuitry for many supplemental capabilities, such as a fax modem, and are made to fit a particular type of bus (also referred to as expansion cards).
Expansion bus: An extension of the common electrical bus that accepts the expansion boards that control the video display, disks, and other peripherals. (see also bus).
Expansion slots: Slots within the processing component of a microcomputer into which optional add-on circuit boards may be inserted.
Export: The process of converting a file in the format of the current program to a format that can be used by another program. (Contrast with import).
Extended memory: In a personal computer running DOS, extended memory is memory above the 1MB address range. Normally, this memory is available to DOS only as a virtual disk (memory that is treated as though it were a disk drive).
Extranet: An extension of an intranet such that it is partially accessible to authorized outsiders, such as customers and suppliers. {Back to TOP}
F
Facsimile (fax): The transferring of images, usually of hard-copy documents, via telephone lines to another device that can receive and interpret the images.
FAQ (Frequently Asked Questions): Compiled lists of the most frequent questions and their answers on a particular topic. A FAQ generally can be found in various formats, such as HTML (Hyper Text Markup Language) Web pages, as well as traditional printed material.
Fax modem: A modem that enables a PC to emulate a facsimile machine.
Feedback loop: A closed loop in which a computer-controlled process generates data that becomes input to the computer.
Fetch instruction: That part of the instruction cycle in which the control unit retrieves a program instruction from RAM and loads it to the processor.
Fiber optic cable: A data transmission medium that carries data in the form of light in very thin transparent fibers. Usually operates utilizing laser light sources.
Field: The smallest logical unit of data in a database. Examples of three fields in a database table are employee number, first name, and price.
FIFO (First-In-First-Out): Refers to a caching methodology in which the oldest item in a queue is the first to be retrieved.
File: (1) A collection of related records. (2) A named area on a disk-storage device that contains a program or digitized information (text, image, sound, and so on). (3) A component of an overall program or appliocation.
File allocation table (FAT): MS-DOS’s method of storing and keeping track of files on a disk.
File attributes: Designations that regulate how a file may be handled on the network. For example, a file can be assigned the attributes “Shareable” and “Read/Only.” “Shareable” means that more than one user may access the file at the same time; “Read/Only” means that users may read the file, but they cannot alter it.
File compression: A technique by which the size of a file can be reduced.