ACCC Glossary of Computer Terms, A-C

Contents

Numerics and Others | A | B | C

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List of Defined Words

10BaseT:
:-)
Abend
Academic Computing and Communications Center
Academic Data Network or ADN
Account
ACF
Ada
Address book
ADN
AIFF
ANSI
ADSM
APL
AppleTalk
ARC
Archive
ARCUTIL
ARPANET
Ascenders
ASCII
Assembler
Asynchronous
ATM
ATM address
AU
AUI
AVI
Backbone network
Background
Backup
Bandwidth
Baseband cable
Baseline
base64
BASIC
Batch Jobs or Batch Processing
Baud
Bell 103A
Bell 212A
Binary
BISYNC
Bit
Bitmap
BITNET
Block
BMDP
BMP
BootP
Borg
bpi
bps
Bridge
Broadband cable
Browser
Buffer
Bug
Bulletin board systems
Byte
Cable modems
Carrier detect
CCITT
CDI
CD-R
CGI
Channel
Chicago NAP
CIC and CICNET
Client
Client-server computing
Clock cycle
CMS
Coaxial cable
COBOL
Codec
Color depth
Compiler
COM port
Compression
Connectionless transfer
Continuous tone
Control character
Courseware
Coupler
CP
CPU
Crop
CRT
CSNET
CTS
Cylinder

+--+ Numerics and Others +--+

10BaseT:

The IEEE 802.3 LAN protocol specification which is used on the ADN-ii ethernet network, running at 10Mbps over unshielded twisted pair wiring.

:-)

A "smiley" -- turn your head ninety degrees counter-clockwise and you will see why it is called that. You type this in electronic messages to indicate that what you've just said is meant to be funny. For example: "... Oh, I'm telling your mother on you!!" sounds harsh, but: "... Oh, I'm telling your mother on you!! :-)" would be taken lightly. There are many other recognized smileys which express different emotions, for example, :-(, or which draw the smiley face differently, for example, 8-), a smiley face with glasses. Also called emoticons.

+--+ A +--+

Abend

Abnormal ending. Various things may cause your program to abend, for example, exceeding job resource estimates.

Academic Computing and Communications Center

The UIC Academic Computing and Communications Center, serving the academic- and research-related computing needs of the faculty, staff, and students of the University of Illinois at Chicago. Also known as the ACCC.

Academic Data Network or ADN

A local UIC campus-wide network which is part of the nationwide Internet computer network. The TCP/IP protocol suite is used to communicate on the ADN network. See also FDDI, Ethernet and 10BaseT. Also see the ACCC Computing Services page.

ACCC

See Academic Computing and Communications Center.

Account

A data record in the computer indicating a person's authorization level and available resources. See the ACCC Accounts page for more information on ACCC accounts and on opening yours.

ACF

Obsolete. The Access Control Facility: ACF was a CMS/MVS utility that allowed users to choose who can access their stored data.

Ada

A programming language developed by the Department of Defense in the early 1970's as a standard language for real-time and concurrent applications. It is a general purpose, block-structured language.

address book

A small database in which you store email addresses for the individuals and groups that you correspond with, each labelled with an easy to remember nickname. Use the ACCC Email Address Conversion Utility to convert your addressbooks from one email platform to another.

ADN

See Academic Data Network.

AIFF Audio Interface File Format

A Mac format for 8-bit and 16-bit digital audio.

ANSI

American National Standards Institute: The principle United States organization for the development and publication of industry standards.

ADSM

ADSTAR Distributed Storage Manager: An IBM product which provides services for backing up, archiving and restoring data files by allowing a central workstation to act as a server for networked workstations and personal computers. ADSM is available at UIC, for use with personal computers which are attached to the UIC campus computer network. See ADSM Network Backup. The ADSM service is also available on tigger and icarus.

APL

A Programming Language: A high level computer language used for mathematical manipulations; not available on the ACCC's machines.

AppleTalk

A suite of transport protocols introduced and maintained by Apple. Software that supports AppleTalk protocols is included in all newer versions of MacOS.

ARC

Data compression and file packaging program for personal computers.

Archive

Offline storage system for data which is not actively being used. The ACCC no longer offices data archiving service. (You're much better off using a personal computer that has a CD-ROM read/write drive.) See also Backup.

ARCUTIL

Obsolete. Was an data archiving and encoding system for VM/CMS.

ARPANET

Advanced Research Project Agency Network: A research oriented network developed by the Defense Advanced Research Agency of the Department of Defense (previously called DARPA) using the Internet protocols. ARPANET evolved into the Internet; the name ARPANET was officially retired in 1990.

Ascenders

A text formatting term: The portion of any character which extends above the height of a lower case "m". See also descenders.

ASCII

American Standard Code for Information Interchange: The ANSI standard code for sending alphanumeric characters through electronic equipment such as computers and terminals. ASCII uses an 8-bit code for character representation; 7 data bits and a parity bit. IBM is big and powerful enough to stick with their own code for their mainframe computers: EBCDIC.

Assembler

The assembler language is a symbolic programming language which allows writing machine level instructions with simple mnemonics rather than numeric instructions. The term "the assembler" also refers to a program that translates symbolic machine language into actual machine language.

Asynchronous

A method of transmitting blocks (or packets) of data that permits arbitrary spacing between individual characters. Transmission is controlled by start and stop bits at the beginning of each block.

ATM

Asynchronous Transmission Mode; a high-speed, connection-oriented, transmission standard for WANs and LANs, with 53-byte cells, 5-byte header, and 48-byte payload. For more information, see the A3C Connection article on ATM: Building the Data Highway.

ATM address

a unique 20-byte hierarchical address using prefixes similar to telephone country codes, area codes, and exchanges, identifying every node on any ATM network; ATM addresses label machines in ATM switches' routing tables. Unlike IP addresses (which are carried in the address information with each cell), ATM addresses are only used on an ATM network to set up the path for a connection.

AU

Sound file format, originally for SUN UNIX systems, now also supported on PCs and Macs.

AUI

Attachment Unit Interface: An IEEE 802.3 (ethernet) cable connecting the MAU (Media Access Unit) to the networked device. Also called a transceiver cable.

AVI AudioVideo Interleaved

Microsoft's native video for Windows movie format for storing video with audio.

+--+ B +--+

Backbone network

A local area network like the ACCC's ADN, which acts primarily as a conduit for traffic to and from other networks.

Background

Using computer resources in a non-interactive way, at the discretion of the operating system. Background jobs usually do not interfere with your ability to use your account interactively.

Backup

To make a copy of a data set for safety purposes. Backups can be either to disk or tape. The ACCC does daily and weekly ADSM backups of files on the ACCC UNIX workstations. ADSM backup for registed on-campus personal computers can also be scheduled automatically; see ADSM Network Backup.

Bandwidth

The amount of data that can be carried on a wire or other transmission medium, measured in bits per second, bps; directly related to the difference between the highest and lowest frequencies that can be carried on it. In other words, the range of useful frequencies of a communications signal or channel. See also baseband and broadband.

Baseband cable

A type of cable connection used in computer networks which is highly reliable and easy to manage, but which uses only one carrier frequency, and therefore is capable of transmitting only one message at a time. See also broadband cable.

Baseline

A text formatting term: The baseline of a text is the lowermost point of the body of the letters, not including descenders (the lower parts of letters like "g" and "j").

base64

The binary to 7-bit ASCII encoding scheme developed to allow binary files to be attached to MIME email messages. See also MIME.

BASIC

Beginner's All-purpose Symbolic Instruction Code: A simple to learn and easy to use programming language.

Batch Jobs or Batch Processing

In batch processing, the program and data to be processed is collected with the commands needed to execute the program, and submitted to the operating system. The submitted batch jobs are kept in disk storage until execution; and they are selected for execution by the operating system in order by job class and priority. See also Interactive processing.

Baud

A measure of the speed of data transmission, equal to the number of discrete conditions or signal events that can be sent or received per second. Baud is the same as bps (bits per second) only if each signal event transmits only one bit.

Bell 103A

An AT x standard for modems providing full duplex, 300 bits per second, asynchronous or synchronous transmission over the public telephone network.

Bell 212A

An AT x standard for modems providing full duplex, 1200 bits per second, asynchronous or synchronous transmission over the public telephone network.

Binary

A numbering system with only two digits; 0 and 1, where 0=off and 1=on.

BISYNC

Binary Synchronous Communication, aka BSC. A transmission protocol used by IBM mainframes. BISYNC gathers a number of message characters and puts them in a single, large message block that includes special characters, synchronized bits, and station-addressing information.

Bit

A BInary digiT: The smallest piece of data possible, a "1" or a "0". 8 bits make up a "byte"; one byte can represent a single character.

Bitmap

2-D array of pixels representing video and graphics.

BITNET

Because It's Time NETwork or Because It's There NETwork: A network of educational sites separate from the Internet; . Listservs, the most popular form of email discussion groups, originated on BITNET. UIC was one of the first members of BITNET and one of the last. UIC withdrew from BITNET November 1, 1996.

Block

In communications, a group of individual data elements sent, received or stored as a unit to increase transmission efficiency. See also packet.

Also a text formatting term: In some text editors or word processing packages, there are block commands which allow you to mark a block of text to be treated or processed as a unit.

BMDP

BioMeDical computer Programs: A set computer programs that provide a wide variety of analytical capabilities that range from plots and simple data descriptions to advanced statistical techniques. See the ACCC Statistical Resources and Information page.

BMP

A Windows native format for a bitmapped graphics file. See also Bitmap.

BootP

A protocol that is used by a network node to determine the IP address of its Ethernet interfaces, in order to effect network booting.

Borg

The ACCC's Convex Exemplar supercomputer, borg.uic.edu. See the Borg home page.

bpi

Bits Per Inch per track: A measure of the recording density on magnetic computer tape. For example, on a nine track tape written at 1600 bpi, you can store 1600 bytes (200 80 character records) on an inch of tape.

bps

Bits Per Second: A measure of the speed of transmission of computer data. See also Baud.

Bridge

A communications device which is used to connect two networks which communicate in an essentially similar manner. See also Gateway.

Broadband cable

A type of cable used in computer networks which can carry several messages at the same time, but which is somewhat difficult to install and manage. In contrast to baseband cable, broadband cable multiplexes multiple independent signals onto one cable. For home Internet access, your principal broadband choices are cable modems, which run on Cable TV wiring, and several varieties of DSL (Digital Subscriber Line), which run on standard copper telephone telephone lines.

 

Browser:

A WWW client program that can "speak" at least HTTP and gopher, and can interpret HTML documents. Examples are Mosaic and Netscape (both for Windows, X Windows, and Mac) from NCSA, Lynx (UNIX/VT100) and DosLynx (DOS) from the University of Kansas, and Cello (Windows) and Viola (X Windows) from Cornell. Netscape for Macintosh and Netscape for Windows are included in our Network Services Kit.

Buffer

A storage device which compensates for the differences in the rate of data flow during data transmission between devices.

Bug

An error in either computer hardware or software. Finding and correcting errors is known as debugging.

Bulletin board systems

BBS: An electronic information system. See the ACCC Netnews / Usenet page. See also NETNEWS and USENET.

Byte

A byte is 8 bits; one byte can represent a single character. On most machines, the byte is the basic unit of addressable memory. On IBM mainframes, a word is 4 bytes (32 bits).

+--+ C +--+

Cable modems

A broadband Internet connection method that uses cable TV cabling; see Connecting from Home.

Carrier detect

A signal from an RS-232 connection indicating that a communication connection has been established with a remote system.

CCITT

Comite Consultatif Internationale de Telegraphique et Telephonique, or the Consultative Committee on International Telphone and Telegraphy. The CCITT is now known as the ITU-T (for Telecommunication Standardization Sector of the International Telecommunications Union). An international committee that sets standards for international communications. The CCITT standard data modems needed for telephone communications on the ACCC's public dial-in telephone lines are: CCITT V.32-bis for 14.4 Kbps, CCITT V.34 for 28.8 Kbps and 33.6 Kbps. For more information, see internet.com's PC Webopaedia entry CCITT, or see the ITU home page.

CDI Compact Disc Digital Interactive

A compact disk standard developed by Phillips for CDs containing a mix of sound, images, and interaction; for CD players following the Green Book.

CD-R Compact Disk-Recordable

A multi-session CD-ROM recording format; requires a multi-session CD-ROM drive.

 

CGI:

Common Gateway Interface. A protocol used by HTTPD to channel information from a browser to a custom program (such as a database interface) and to return the result of the custom program to the browser.

Channel

A special purpose computer used for communication between a main computer and an external device, such as a disk or tape. Also, in networking: a communications link between two or more points; also called a circuit, path, or link. (ATM's use of "path" is different, though; see PVP.)

Chicago NAP

Ameritech's Chicago Network Access Point. See also NAP.

CIC

Committee on Institutional Cooperation, academic consortium consisting of the Big Ten universities along with the University of Chicago, the University of Illinois at Chicago, and the University of Pennsylvania. CICNet is a now-retired computer network connecting the CIC universities and other organizations in the Midwest.

Client

A front end device (a node or software program that requests services from a server. See also Server.

Client-server computing

A distributed computing network system in which each transaction is divided into two parts: a front end client, and a back end server, which are two different devices or programs. See RPC. See also Peer-to-peer computing.

Clock cycle

The unit of type used by the basic timing system of a computer. The clock cycle is used to measure the computer's theoretical performance. The clock cycles of the ACCC's IBM 3090/300J/VF computer is 14.5 nanoseconds.

CMS

Conversational Monitor System: The most widely used interactive computer system at UIC. CMS runs under the VM operating system on UICVM.

Coaxial cable

A cable with a hollow outer cylindrical conductor surrounding a single inner while conductor.

COBOL

COmmon Business Oriented Language: An old but still commonly used programming language primarily for business applications.

Codec

Compression/decompression.

Color depth

Number of colors in an image: 8-bit (256 colors), 16-bit (32,768 colors), and 24-bit (16.4 million colors).

Compiler

A program that translates a high level symbolic language to a low level machine language, FORTRAN, Pascal, and PL/I are familiar compilers.

COM port

The DOS name of the serial ports on PC's.

Compression

Running data through an algorithm which reduces its size to reduce the space or bandwidth needed to store or transmit it. See also encoding.

Connectionless transfer

Data transfer without a virtual circuit (a preselected path for the transfer); IP is a connectionless protocol; FTP and ATM are not.

Continuous tone

An image made of blended levels of gray flowing into each other without hard delineations.

Control character

A byte of data (a character) whose occurrence initiates, modifies or stops an operation.

Coupler

An acoustic device sometimes used to establish a phone connection between electronic devices such as a terminal and a computer.

Courseware

Software containing instructional material, educational software, or audiovisual materials.

CP

Control Program: The interactive part of the VM operating system. CMS users encounter CP when they LOGON and LOGOFF, or if their CMS session is interrupted.

CPU

Central Processing Unit: The "brain" of the computer which performs most computing tasks.

Crop

A text formatting term: To trim the edges of a graphic image, removing part of the image.

CRT

Cathode Ray Tube: A terminal with a TV screen and keyboard.

CSNET

Computer Science Network. A larger computer communication network consisting of universities, research institutions, and commercial concerns, which merged with BITNET to form CREN.

CTS

Clear To Send: When using DCE (Data Communications Equipment; a modem is a common example), the CTS indicates that the DCE is ready to accept data.

Cylinder

As related to magnetic disks, a cylinder is a vertical column of tracks on a magnetic disk pack; since the read/write heads can read from any track on the cylinder without being moved in or out, storing multi-track files on cylinders is quite efficient. Cylinder is also used as a unit of storage space. On CMS, a one cylinder minidisk has storage for about 600K bytes.