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									                     Queens University
                     (Prepared by: Prof. Md. Abdul Mannan Sarker)

                       GLOSSARY OF IT TERMINOLOGY:

This Glossary is a comprehensive summary of the terms used within the Computer (IT)
field. Whether you’re a computer novice or an experienced computer operator, engineer,
programmer, vendor, businessmen, executive, Govt. Non-Government officials this
glossary will serve as a convenient reference whenever you need to clarify a term or to
reinforce your understanding of a term. You can use this book as a handbook of
Computer (IT) Glossary for your ready reference. Glossary is a very important
fundamental subject of the Information Technology. Without the profound knowledge of
IT Glossary, nobody can show his/her skills in the IT field. Glossary is a good friend of
the IT journey of your IT life. So everybody should know the Glossary of IT, those who
are interested to maintain a leadership in this line also. Anyone from any profession may
preserve the Glossary within his/her knowledge in the IT Century for himself and others.

Abend: Message indicating an “abnormal ending” to a program execution.
Abort: To conclude a program.
ABS: Absolute magnitude. The absolute value of a number, ignoring any sign. Thus,
ABS (-25)=25.
Absent data check: That part of a data validation program that checks for missing items.
Absolute address: Actual location in storage of a particular nit of data. Also called
machine address.
Access: The processes of finding, reading, and retrieving data from storage. A disk drive
is used to access data on a disk.
Access time: The amount of time it takes to complete a request for data to be retrieved
from storage. A measurement of disk speed where the lower the access time the faster
the disk drive.
Accounting package: Application software that manages finances.
Accumulator: A register in the CPU that holds the results of ALU operations.
Acoustic coupler: A device that allows a telephone handset to be connected to a
computer by translating between electronic signals and audio signals.
Acronym: A word formed from the first letters of several other words. DOS is an
acronym for Disk Operating System.

Active key: Key with the lowest value among those being processed while merging or
updating sequential files.
Activity rate: Frequency with which records are accessed by a given application.
Actual key: In COBOL, a data item used for a machine address.
Ada: High-level computer language named after Augusta Ada Byron, world’s first
Adapter: Connector within a system or subsystem, or between systems and/or
ADC: Analog-to-digital converter.
Adder: Device that outputs the sum of two or more input numbers.
Add-on memories: In large-scale integration, memory boards added as needed to
enhance a unit’s overall capability.
Address: A unique location in memory or in auxiliary storage where data or programs
are stored for future use. A coding scheme used to store and retrieve data from memory
or auxiliary storage,
Address register: Indicates the location of data to be stored or retrieved from primary
A/D Interface: “Building block” subsystem for implementing ADC
AI: Artificial Intelligence. The programs can enable a computer to simulate human
thought and judgment. Such programs are known as artificial intelligence (AI)
ALGOL: Algorithmic Language, a contemporary computer language.
Algorithm: Series of orderly steps for defining and solving specific problem.
Alphabetic: In COBOL, of data consisting only of the letters A-Z and blank spaces.
Alphanumeric: Consisting of any combination of letters, numbers, and special symbols.
Alt: Abbreviation for the alternate key found on most personal computer keyboards.
Used to access special functions including system boot. The Alt key functions the same
way the Shift key does. To use a function that requires the Alt key hold it down while
striking the other keys.
Alternating format: Logic used to locate desired data in a table through comparison
with a search argument.
Amblent conditions: Atmosphere; surroundings including such factors as noise,
pressure, etc.
Analog: Describing a signal that has a continuous range of voltage or current values.
Analog computer: A computer that operates by creating a physical (usually electrical)
analogy of the mathematical problem to be solved.
Analog interface: Circuit that enables a personal microcomputer to monitor and control
no digital universe.
AND: A logical operator that’s used in a comparison of two or more values. If the action
indicated in the comparison is to occur, all of the portions of the comparison must be true.
For example, if A=B and C=D then go to 40.
AND/OR test: A statement (using AND or OR) that forces the computer to check to
determine if more that one specified condition is true.
Animation: Optical illusion created when pages of slightly different graphics text are
displayed on a CRT in rapid succession.
ANSI: Acronym for the American National Standards Institute, which sets the standards
for computer languages.

Answer string: A code that enables a modem to answer a telephone.
APL: Acronym of A Programming Language, a contemporary programming language.
Append: Instruction to a telecommunications program to add downloaded data to a
capture file.
Application software: (application package). A collection of related programs or sub-
programs designed to accomplish some specified set of tasks.
APT: Language used to program numerically controlled machine tools.
Architecture: The logical design of the Central Processing Unit or computer system.
Archival file: Permanent copy of records designated for long-term storage.
Argument: The key in a table that locates the desired data.
Arithmetic-Logic Unit (ALU): The part of a CPU that performs): mathematical and
logical operations and manipulates values based on logical comparisons.
Array: A group of logically sequential memory spaces in which data can be stored.
Arrows: Keyboard symbols used to l. move cursor, and 2. Link flowchart symbols.
Artificial Intelligence (AI): The branch of computer science concerned with b building
systems that imitate human thought processes or decision-making. (Programs can enable
a computer to simulate human thought and judgment. Such programs are known as AI)
ASC: Function that returns the computer’s code value of any character.
Ascending: Describing a sequence of data such that each number is larger than its
ASCII: Abbreviation for American Standard Code for Information Interchange. A
system of coding used by most personal computers to represent numbers, letters and
special symbols internally. A binary coding scheme used to store data in a computer.
ASR keyboard: Acronym for automatic send-receive keyboard, a unit modeled after the
33-key teletypewriter keyboard.
Assembler: A computer routine for converting assembly language into machine language.
Assembly language: A low-level, machine-specific programming language that allows
programmers to use mnemonics for operations and symbols for variables.
Astable circuit: A circuit that alternates continuously between its two unstable states.
Asterisk (*): Wildcard key.
Asynchronous Communications Interface Adapter (ACIA): A device providing the
data formatting and control necessary to interface serial asynchronous data
communications information to bus-organized systems.
Asynchronous transmission:           The sending of one character at a time over
communications channels.
(@): Function used to control the location on the screen where data is displayed.
Authorization: Processing control function that permits or forbids the acceptance of
Autoexec: A batch file that automatically executes every time a computer is turned on or
rebooted. An abbreviation for automatically executed.
Auto log file: A set of instructions for accessing telecommunications service.
Automated teller machine (ATM): A remote terminal programmed to perform many of
the functions of human bank tellers, such as dispensing cash, receiving deposits and
payments, and reporting account balances.

Auxiliary storage: Location for storing data in a permanent form for later use. Disks,
diskettes, tapes, and CD-ROM are all examples of auxiliary storage. A device used for
the permanent storage of data on a computer.
Avalanche diode: A diode that switches the circuit through it rapidly whenever the
applied voltage increases. Also called breakdown diode or zener diode.

Background: A method by which two jobs or functions can be processed at the same
time. (One is in the “foreground” the other is in the “background”.) Frequently used with
printers, the computer will process the print function while running another program. A
job that has low priority that will be processed when the computer is not being used for a
high priority job.
Back plane: Connector blocks and wiring units that form system circuitry.
Backspace key: Key that enables the user to move the cursor one space to the left (and,
in some programs, to delete).
Backup: The term used to describe the process of making copies of data or a program in
case the original is lost, destroyed, or becomes unusable.
Badge reader: Industrial device that senses data from a badge inserted by an employees.
Balance line algorithm: Generalized approach to sequential file updating that provides a
control key value against which other keys are balanced.
Balancing: Processing-control technique in which a computed value is compared with an
independent value specifically entered for control purposes.
Bandwidth: The range of frequencies that can be accurately transmitted over a
communications channel.
Bar codes: A means of representing data as a series of machine-readable white and black
BASIC: Acronym for Beginners All-Purpose Symbolic Instruction Code.                     A
programming language that’s supplied with most personal computers. A multipurpose
language that’s easy to learn and use.
Basic Data Processing Cycle: Any facts are entered into the Computer that controlled,
stored and arithmetic operations by CPU and displayed on the screen or printed in
finished or edited forms. The functions of the refined data are collectively called Basic
Data Processing Cycle.
Batch: l. A method of processing a set of commands from start to finish without user
intervention. A user will submit the initial command to start a batch process after which
no interaction is required.. 2. To process a group of data at one time. For example,
processing a month’s worth of receipts at the end of the month.
Batch file: A collection of commands stored in the same file that will be processed in a
batch. Batch files usually have a BAT extension.
Battery pack: Back;\up power-supply unit for RAM and other components.
Baud: A unit used to measure transmission speed, equivalent to bits-per-second.
Baud rate: The speed at which data is transmitted over a cable. Usually refers to
telephone line transmission. Common baud rates are 300, 1200,2400, and 9600. The
higher the baud rates the faster the transmission speed.

BBD: Bucket brigade device: Charge-transfer device in a semiconductor.
Bbox: Address-3 modification registers.
Benchmark program: Routine program for testing or comparing different types of
Bezel: Protective plate over computer area where optional equipment may be added.
Bi-directional bus: Data bus in which digital information can be transferred in either
Bi-directional printing: Capability of a serial printer to print both left-to-right and right-
to left.
BiMOS: Technology combining MOS and bipolar devices on the same chip
Binary-coded decimal: A method of coding data using only the numbers one and zero.
The method of representing data that most computers use. A coding system in which the
number one usually represents on, true, positive, or yes, and zero is usually used to
represent off, false, negative, or no.
Binary digit: Refers to the numbers one or zero when used in binary code.
Binary search: Type of search in which a sequentially ordered table is iteratively divided
in half to search for a given value.
Binary system: A number system in which the digits of each number indicate what
powers of 2(1,2,4,8,16, etc.) it contains.
Binary tree: Special type of tree data structure with nodes in ascending order.
Binding: Assignment of absolute addresses to a program.
Blochip: Hypothetical organic computer chip.
Bipolar: A technology of integrated circuit fabrication, which uses transistor switching
elements for amplification and switching.
Bipolar PROM: Programmable ROM with very fast access time.
Bit: One binary digit, either a 0 or 1.
Black box: The internal components and functioning of a computer that perform in an
unknown n manner.
Blast: The release of various specified areas or blocks of storage that are no longer
essential to the program at hand.
Block: A group of records handled as a unit in order to speed processing.
Blow up: To lose (a program) due to error.
Board: A sheet used for mounting integrated circuits.
Bonding pad: The metallic area on a chip designed for the connection of wires.
Boolean algebra: Mathematical system of logic functions using operators such as AND,
OR, etc.
Boot: To start or reset a computer. To boot a personal computer the user can simply turn
the power on if DOS is available to the computer. If the computer is already on the user
can hit the Control, Alt, and Delete keys at the same time. The word boot is derived from
the world bootstrap.
Bootstrap: Device designed to bring itself into a desired state through its own actions. To
function as or use a bootstrap.
BPI: Bits-per-inch the unit of measurement for the density of data on a tape or disk.
Branch: To jump to an alternative action, rather than to the next instruction in sequence.
Breadboard: A temporary arrangement of electronic components fastened to a board for
purposes of experiment; a model.

BREAK: Keyword used to stop a program or list.
Break key: Keyboard key whose function depends on the computer program in place.
Breakpoint: The point in a program or routine where a scheduled interruption takes-or
may take-place.
B register: A computer register in which is stored a word capable of changing a given
instruction as desired.
Broadband channels: Communications pathways with a bandwidth greater than 3000
hertz and a transmission rate as high as several million characters-per-second.
Browse: A feature of data base software programs that allows the user to view all the
records in the database.
Bubble: Circular symbol representing processing step in a data-flow diagram.
Bubble memory: Memory system that stores information in the form of tiny magnetic

Bubble sort: A method of arranging records so that the smallest (lightest) values “float”
to the top.
Buffer: A temporary storage location where data is stored until it can be used. Data sent
to a printer is often stored in a buffer until the printer is ready for it.
Bug: Term used to denote a problem or error in a program.
Bulletin board: A service that allows user computers to communicate with a central
point over telephone lines for the sharing or transferring of data, programs, and
Burst: In data transmission, a series of signals reckoned as a single unit.
Bus: A group of wires that connect the various internal and external components of a
computer system with its CPU.
Bus driver: A specially designed IC in the data bus system that facilitates drive to the
Byte: A group of bits.

C: A high-level programming language.
Cache memory: Very fast but spatially limited semiconductor memory.
CAD: Acronym for Computer-Aided Design. Refers to software that supports graphic
and drafting functions.
Calculator: Elementary computational device operated by pressing keys.
CALL: COBOL verb used in joint subprogram/main program applications.
Called program: A program invoked in its object state to which control is transferred
from a calling program.
Caller: A line in a program that requests a branch to a subroutine.
Calling program: A program in which a CALL command is introduced to transfer
program control to a called program. Also called main program.
CAM: Computer-aided manufacturing; content-addressable memory.
Capacitor: A device for storing electrically separated charges.

Caps Lock key: Keyboard key used for extended capitalization.
Capstan: A rotary device within a tape drives that friction-feet’s tape for reading or
writing upon.
Capture file: In telecommunications, the repository of the data downloaded from a
Card: A collection of electronic components mounted on a flat surface usually designed
for a specific function. Most personal computers have several cards. A group of
electronic components that can be inserted into or removed from a computer as a single
Card reader: A device that “senses” the coded holes a punched card, and translates them
into bit patterns.
Carriage control: The printer-control function that establishes the pattern of vertical line
spacing in a printed report.
Cartridges: Electronic circuit boards containing programs and information.
Case construct: The control structure within a structured program that’s designed to
select between or among processing alternatives.
Cassette: A two-reel magnetic tape cartridge used for storing computer programs and
processing data.
Cathode-ray tube (CRT): A device in which a raster scan technique produces images on
a screen; the basis of the majority of computer displays now in use.
CCD: Acronym for charge-coupled device, a semiconductor that stores and, when
stimulated, transfers a charge representing digital information.
CCITT: Acronym for International Telegraph and Telephone Consultative Committee.
The worldwide committee that establishes standards for the communications industry and
computer equipment that use telephone and telegraph to transmit and receive data.
CD-ROM: Stands for Compact Disk Read-Only Memory. A device used to store data
from a computer digitally onto a compact disk through the use of a laser. Once stored,
this data becomes permanent and can be recalled using the same device. A device similar
to audio compact disc players but is used to store and retrieve computer data.
Cell: Each usable position in an electronic spreadsheet identified by its row and column.
Call address: A designation that specifies the cell’s exact position in a worksheet.
Cell pointer: Marks the location in an electronic spreadsheet where data can be entered
or commands initiated.
Central Processing Unit (CPU): The collective name for the registers, the arithmetic
and logic unit, and the main control unit of a computer system.
Compiler: A general-purpose micro processing programming language.
CGA: An acronym for color graphic adaptor. A device that allows a computer to utilize
color and graphic functions on a display. CGA is the oldest of the color adaptors and has
the fewest number of functions. Chad: The tiny piece of paper displaced when a hole is
punched into a card or paper tape.
Chaining: A technique for dividing a lengthy computer program into two or more
smaller, more manageable units.
Chain pointer: The data field added to a home address record to note the address of a
Channels: Special-purpose microcomputers or minicomputers that control the movement
of data between a CPU and input/outpour devices.

Character: The smallest unit of computer data-a single letter, numeral, or symbol.
Character printers: Machines that print a single character at a time, one after another,
across the paper from margin to margin.
Character string: A sequence of characters.
Character testing: A validating process that tests whether input characters are
acceptable for processing and/or storage.
Charting program: A program that produces graphs, plots and charts from numeric data
transferred from spreadsheet or data base file.
Check register: Register designated for the temporary storage of information.
Child: One of the two or more lower-level nodes in a tree data structure. Also called
Chip: An electronic component cut from silicon and having circuits etched into it. Most
chips are smaller than a fingernail. Common examples include RAM and ROM memory
CIRCLE: BASIC keyword that allows for the drawing of circles, ellipses, and arcs on a
graphics screen.
CIS: Acronym for Computer Information System.
Class condition: The presence within a field of data of wholly numeric or alphabetic
Class interrupt: An interrupt used to report on results of internal checking by the CPU.
Class test: In a COBOL selection statement, a condition test aimed at verifying data
Clause: One part or element of a program sentence or statement.
CLEAR: The keyword that reserves extra memory space for string variables.
Clipboard: A temporary file for holding excised portions of text.
CLOAD: The command for accessing a saved BASIC program from tape.
Clone IBM compatible.
CLOSE: l. An I/O verb in COBOL 2. The BASIC keyword that ends access to a
previously opened disk or tape file.
CLS: Screen-clearing keyword.
CMOS: Acronym for complementary metal oxide semiconductor, a semiconductor
manufacturing technology distinguished by low power dissipation but somewhat
compromised by product size.
COBOL: A high-level programming language used primarily for business applications.
COBOL is an acronym for Common Business Oriented Languages.
CODASYL: Acronym for the Conference on Data Systems Language, from which
conclave the development of COBOL proceeded.
Code: A system used to describe something in another form. Codes are used to condense
information into the smallest possible space thereby saving memory and disk capacity. A
typical example of a code use din computers is Binary Code.
Codec: The microelectronic coder-decoder, a unit that translates analog voice signals
into digital pulse-code modulation, and vice versa.
Coding: The process of expressing computer algorithm in standard programming
Cohesion: The condition of interrelatedness among the elements in a program module.

Coincidental Cohesion: The lowest-level and least desirable form of interrelated-ness
of module contents.
Collate: A program routine for merging records.
Collating sequence: The relative values assigned to the characters on a computer
Collator: A punched-card machine for merging two sets of cards into one.
COLOR: BASIC keyword that sets the default colors for foreground and background.
Colpitts oscillator: A type of oscillator consisting of two resonant-circuit capacitors and
a tap.
Command: A word, sentence, or symbol that when entered into a computer causes a
particular function to be performed. The DOS copy command is an example. When the
user types the word “copy” with the correct parameters, the computer will execute the
instructions to create a copy of a file.
Command line: The point on the screen where the instructions appear in a spreadsheet.
Comment: A statement used to provide information to the user, but ignored by the
computer during program execution. Also called comment line.
Communicational cohesion: Cohesion resulting from the processing of identical input
or output data items by multiple instructions, or elements, of a single module.
Communications: Term used to describe the transfer of data usually over cables or
telephone lines between computer systems.
Communications package: Software that allows one computer to “talk” to another.
Compatible: Of an item of computer hardware or software, adaptable to the hardware of
more than one manufacturer.
Compilation: The translation by a compiler of source instructions in order to generate a
machine-language object program.
Compiler: A program used to translate a high level language, e.g. , COBOL, into
machine readable instructions.
Compile-time table: A table used in COBOL to convert codes to descriptions.
Completely modular computer: An extremely expandable computer using individual
circuit boards.
Component: One of the parts of which a whole is composed.
Compound comparison: A statement (using AND or OR) that forces the computer to
heck to determine if more than one specified condition is true.
COMPUTE: I/O verb used in COBOL to perform multiple math functions in one
Computer: An electronic device that allows instructions and programs to be stored and
executed so that meaningful tasks can be performed.
Computer-aided design (CAD): The application of interactive computer graphics to
product design.
Computer-aided Engineering (CAE): The application of computer programs that
simulate complex electrical or mechanical systems to the design and development of
Computer-aided manufacturing (CAM): The application of shared databases and
computers to all aspects of production.
Computer-assisted instruction (CAI): The use of computers to facilitate the process of

Computer-based monitoring: Constant evaluation by computer of an employee’s
performance in terms of time, quantity, and quality.
Computer conferencing: The use of a telecommunications link to join distant
computers and terminals so that users can exchange information or messages
immediately and directly.
Computer-information system (CIS): A total computer system, including hardware,
software, appropriates personnel, and other resources.
Computer-input microfilm (CIM): Computer input in the form of micro images
recorded on film.
Computer-output microfilm (COM): Computer output in the form of Micro images
recorded on film.
Computer program: A precise, ordered group of statements that specifies how a
computer is to execute a well-defined task.
COMTRAN: A pre-COBOL business-oriented programming language.
Concatenation: The combination of multiple string values into a single value.
Concentrator: A device for multiplexing a number of low-speed communications lines
into one high-speed line.
Condition code: A code containing information on the results of the most recent CPU
Condition name test: A condition test for determining whether a user-defined
descriptive term is true for a value (or set of values) that applies to the data item under
Configure: To set up a computer, peripheral device, or program for the first time. This
process allows the user to define how and when an item will be used.
Connect message: In telecommunications, a signal indicating an open line to the
number called.
Connector symbol: A circular symbol indicating the next instruction to be performed on
a flowchart.
Console: The control panel used by mainframe computer operator to enter commands.
Constant: A data element that maintains the same value throughout a program. Any
value that doesn’t change. An example of constant is “2120F is the boiling poi nt point
for water”
Continue: The keyword used to restart a program.
Content-addressable memory access: The capability of some read/write RAMs to
produce data addresses in response to certain inputs.
Content coupling: The least desirable form of coupling.
Control break. 1.The point in a program where some special process takes place. 2. A
change in program action due to a change in the control field.
 Control coupling: Coupling that occurs when one module passes a control field directly
into the inner structure of another module.
Control field: A field (group of bytes) used to identify a group of records.
Control key: l. A keyboard key used in conjunction with another key to send a command
to the computer.
Controlled loop technique: A method of establishing a fixed number of iterations
within a program.
Controller ambiguity: Inherent error due to multiple bit changes.

Control report: An interim report for checking the accuracy and completeness of
processed data.
Control structure: The patter of logic flow in a given computer program.
Control total: The accumulated numeric data fields used to check data accuracy.
Control Unit: The element in a CPU or Microprocessor that interprets instructions and
regulates data movement through computer storage.
Coprocessor: A hardware device that’s inserted into the system unit that does some of
the work the CPU would normally handle allowing the computer to complete requests
faster. Usually used with complex math functions and applications that require many
mathematical calculations.
COPY: The instruction to duplicate a program, or to file it on another disk.
Copy protected: Term used to describe software that has some form of security built in
that prevents unauthorized copies. Refers to methods used to prevent copy violations.
Coupling: The interdependency of program modules.
CPI: Acronym for Characters-per-inch. A unit of measurement that refers to the number
of letters or numbers a printer can print in one horizontal inch across a page.
CPS: Acronym for characters-per-second. A common rating for the speed at which a
printer works.
CPU: Acronym for Central Processing Unit. That part of a computer that performs
calculations and carries out instructions.
Crash: To cease to function due to internal error or hardware/software malfunction.
Crippled leapfrog test: A program designed to uncover computer malfunction.
CROM: Control ROM, a specific read-only memory designed to decode control logic.
Cross assembler: A program runs on one computer for the purpose of translating
instructions for a second computer.
Cross foot: The addition of several horizontal fields of information from cards or across
a document.
Cross-reference listing: Printout showing l. all data name in a program, and 2. The
name of the module where such data names are referenced.
CRT: Acronym for cathode-ray tube. Refers to the television like screen or monitor that
personal computers use for input and output of data.
CSAVE: A BASIC command to the computer to save a program on a tape cassette.
Cursor: A blinking underscore, vertical bar, or box that marks the exact position on a
screen where text is to be inserted or where some other operation is to occur.
Cut-and-paste: A word-processing feature that lets the user select a part of a document
and move it somewhere else in the document.
CVSD: Acronym for continuous variable-slope delta-modulation detector, a device that
uses a ROM code to create a facsimile of a sound waveform.
CWP: Acronym for communicating word processors, a special desktop computer
embodying copying and communications capabilities.
Cycle time: The time required for a component to complete its operation.

D/A: Digital-to-Analog. Of a code, converting from digital (computer) to analog signal.
Also written to a.
DAC: Acronym for digital-to-analog converter, a device that converts a digital signal into a continuous
electrical signal suitable for input to an analog computer.
Daisy-wheel printer: A type of printer that has a print device that resembles a wheel where each character
is on a spoke and the wheel is rotated to produce the characters. A type of letter quality printer.
Data: Information input that has not been processed.
DATA: In BASIC, a statement that holds numeric or string data accessed when a READ command is
Data access register (DAR): A register that performs memory address arithmetic for RAM resident stack
Data area: Disk area containing an indexed-sequential file.
Data base or database: A collection of related or similar data files that together can be processed as a
single unit.
Data base management package: Software that allows the user to organize the access to large quantities
of information.
Data bus: The set of channels that carries data between computer components.
Data communications: The transmission of data between geographically separated computers.
Data coupling: Coupling that occurs when two or more modules share the use of local data fields.
Data dictionary: Set of specifications for the data elements in a data base or application files.
Data entry: Keying data to be used as input to a computer system.
Data file: A group of related data records stored in the same computer file.
Data jack: A device for connecting a user modem to a telephone network.
Data processing: The transformation of data into usable form by sorting, classifying, etc.
Daughter boards: The individual circuit boards that comprise a completely modular computer.
DBMS: Acronym for data base management system, a software program for controlling the accumulation
of data within an organization.
DCB: Acronym for data control block, used in COBOL to describe to the system certain facts about a file’s
data contents.
DDD statement: In COBOL, a statement describing a specific data set or sets.
Debugging: The process of detecting, locating, and correcting logic errors (or bugs) in a computer program.
Decimal number system: The base-l0 number system used in ordinary counting, employing the symbols 0
through 9.
Decision box: A flowchart symbol indicating such alternative paths as the program allows.
Decision table: A table of conditions and actions (IF/THEN) statements that assists a programmer in
designing a table.
Decision tree: A graphic representation using nodes and interconnecting branches, popular as a decision-
making resource.
Decrement: To decrease the value of a number.
Defaults: In word-processing programs, reestablished settings for line length and spacing.
Defensive programming: The use of program instructions to test for and react to anomalous data
Del: Denotes the delete key on most computer keyboards. Used to delete characters from the display.
Delete: To erase or remove a program or file. A physically deleted file or program can no longer be sued.
Delimiter: A character or set of characters that signals the beginning and ending of computer data. A
control character.

Delta clock: A clock that restarts the computer after a momentary fault halts it, or throws it into a closed
programming loop.
Demodulator: A device that detects a modulating signal, removes the carrier signal, and reconstitutes the
Descending: Data arranged so that each unit is smaller than its predecessor.
Desktop publishing: A series of programs that provides text, graphics, page layout, and other features that
allow the user to create newsletters, booklets, and other printed materials in final form.
Destructive writing: Storage-device function designed to erase previously recorded data.
Detail line: An individual line of output pertaining to a single person, thing, or group.
Detail report: A list of all records within a computer-maintained report. Also called detail listing.
Diagnostic: A program that’s used to check computer hardware and search for malfunctioning parts.
Digital: Describing a signal made up of two noncontiguous values, 0 and l.
Digital computer: A computer that processes information represented by combinations of discontinuous
Digital filtering: Computer filtering of a digitized signal.
Digitize: To convert a chart, diagram, or picture into a form that can be stored on a computer.
Digit portion: The last four bits of a byte in the EBCDIC code.
DIM (ensign): The command that reserves consecutive locations in computer memory for the storage of a
table or array.
Diode: The two-terminal component of second-generation computers.
DIP: Acronym for dual in-line package, a type of plastic IC popular in the l970s.
Dip switch: Two-way switches that allow for user specified changes in the way a device will perform.
Dir. : A command to the computer to display an index of diskette files.
Direct access: A method of retrieving information so that only the needed portions are read therefore
avoiding data that may be stored before or after. Disks and diskettes allow for this type of access.
Direct-access medium: A storage medium that allows any particular item to be read at any time without
having to go through all of the preceding items.
Direct-connect modems: Modulating/demodulating devices that plug into standard phone jacks.
Disk: A magnetic storage medium that’s composed of a one or more disks. The term “disk” usually refers
to permanent or fixed units rather than removable ones.
Disk crash: The destruction of data on a disk due to disk drive and/or access arm malfunction.
Disk drive: A device, which is used to read and write data to a disk. Disk drives are usually referred to by
a single letter followed by a colon; e.g. C.
Diskette: A removable magnetic storage medium similar in design to a disk but with smaller capacity.
The common sizes are 3 ½ and 5 ¼ inches.
DISP: In COBOL, abbreviation of disposition (of a data set).
Display: An output device, similar to a television screen, that presents text and graphics. DISPLAY: I/O
verb used in COBOL to contact a printer or other output device.
Division: One of the four basic parts into which all CONBOL program coding is organized.
Documentation: A written record of the development and operation of a computer program or item of
computer equipment.
Doping: The introduction of phosphorus or boron to pure silicon in order to produce a current-carrying
DOS: Short for Disk Operating System. The standard set of programs that run on IBM and IBM
compatible personal computers. A particular computer operating system.
Dot matrix: A type of printer that forms images by creating a pattern of dots on the page.
Double density: A diskette that’s rated to store twice as much data over the same area.
Double-sided diskette: A diskette that’s designed to store data on both sides.
Do until loop: Iteration control structure in which the condition is tested after the resulting action.
Do while loop: Iteration control structure in which the condition is tested before the resulting action.
Download: To copy a file from a host computer, usually a mainframe, to personal computer. This concept
is used when computers are linked together in some type of network.
Downtime: Period of time during which a computer can’t be used because of maintenance, repairs, etc.
DRAW: BASIC keyword that lets user sketch lines on the screen.
Drive:      Electromechanical device that rotates a disk as read/write head moves across disk.
Drop-dead halt: An irreversible program halt.

Drop out: The momentary loss of a data transmission signal due to noise or system malfunction.
DSN: Acronym for data set name, which in COBOL identifies both the user’s unique account identification
and file name.
DTL: Acronym for diode-transistor logic, which describes logic featuring diodes (with transistors used
only as inverting amplifiers).
Dummy record: Normal record definition that includes specifications of fields for record keys, a record-
type identifier, and the rest of the record.
Dump: To transfer the contents of one storage device to another, as from main memory to printer.
Duplex: In communications, simultaneous independent transmission in both directions.
Dynamic access: Access that permits both sequential and random use of a file.
Dynamic stop: A stop in a loop consisting of a single jump instruction.
Dynamic table: A table that’s defined as the program is written and compiled, but whose actual data
contents are loaded from an external storage medium when the program executes

EAROM: Acronym for electrically alterable ROM, a nonvolatile random access re-write memory.
EBCDIC: Pronounced ebb-see-dick. Acronym for Extended Binary-Coded Decimal Interchange Code, a
code used internally by a computer.
Echo: A part of a command or signal that’s repeated on the computer display.
ECL: Acronym for emitter-coupled logic, a bipolar digital IC family four times faster than TTL.
Edge: The node-connecting line in a data structure graph.
Edit: To add, change, or delete a document, file, or program on a computer.
EDIT: BASIC command that allows programmer to alter a statement.
Editor: A program or set of programs that allows the user to edit items contained on a computer.
Edlin: The t3ex6 editor that’s standard with DOS.
EDP: Acronym for electronic data processing.
EEPROM: Acronym for electrically erasable programmable ROM, a memory that may
also be reprogrammed electrically.
EGA: Acronym for extended graphics adaptor. A hardware device that offers enhancements to the color
graphics adaptor (CGA). A device that supports color and graphics on computer displays.
Electronic bulletin boards: Data communications networks that provide means for their users to
exchange messages, programming tips, advice, comments, and software.
Electronic cottage: Workplace/abode of a person connected to his employer by computer.
Electronic data processing (EDP): The automatic entry, receipt, classification, recording, etc., of
alphabetical, numerical, and/or statistical data without the use of tabulating cards.
Electronic funds transfer (EFT): The movement of money into, out of, and between bank accounts by
means of computers and telecommunications technology.
Electronic journaling: Procedure for logging transactions into a computer system.
Electronic mail: A data communications service that employs computers and telecommunications lines to
send and store messages that would otherwise take the form of a phone call, memo, or letter.
ELSE: The element of an IF/THEN statement that causes alternate processing when a condition is false.
Emulation: The process of imitating a computer system device that’s accomplished with hardware and
software. A method that allows different types of devices to work together.
END: Statement that terminates a program.
End key: The key on a computer keyboard that allows the user to return to a previous point in text.
End of file: A pointer that signals that the last record in a file has been reached and there
is no more data.
ENIAC: Acronym for Electronic Numerical Integrator and Computer, the first l940s) large-scale digital
ENTER: A statement signaling that input to the computer is forthcoming.
Enter key: Keyboard key used to skip a line.
Eof: Acronym for end of file.

EPROM: Acronym for electrically programmable ROM, a memory designed for high performance
microcomputer systems.
Erase: To delete or remove an item stored in a computer.
Ergonomics: The study of people’s physical, psychological, and anatomical relationship to their working
Error message: A message that lists problems with a command or program and possible solutions. Error
messages can be looked up in most computer manuals for more information.
Error-trapping: A programming technique designed to head off the entry of invalid data.
Escape key: Key that cancels input that has gone before.
Escape sequence: A set of characters that specify some action of the display screen.
EVALIOATE: COBOL verb used as an alternative to nested Ifs.
Even parity: A magnetic tape pattern used to check character validity.
Exception report: A computer report noting that conditions are outside the range defined as normal
Exclusive-NOR gate: A two-input logic circuit.
Exclusive-OR: A logical operator.
Executive: To complete or to run an instruction or set of instructions on a computer.
Executive: A program for scheduling, loading, and executing predictable system software modules.
EXIT: A COBOL verb used for paragraphing.
EXP(onential): The inverse function to the LOG function.
Expansion board (card, adapter): A circuit board that plugs into an expansion slot.
Expansion slot: an internal connector that allows additional circuit boards containing extra components to
be plugged in.
Expert (power user): Someone who is very comfortable using a computer and who knows how to
manipulate software to produce desired results.
Expert systems: Area of artificial intelligence based on a series of human expert’s judgments.
Exponentiation: The raising of a number to a given power.
Extension: The three-character suffix used in naming computer files. The extension comes after the
period and usually denotes the type of file. For example; BAK, backup copy; BAS, basic program; BAT,
batch file, DAT, data file, EXE, executable file; TXT, text file.
External command: An instruction or procedure, which is, not store in memory and must be loaded from
auxiliary storage. Format and disk copy are examples of external commands.
External delay: Computer downtime attributable to neither system nor human failure.
Extra code: A sequence of machine code instructions, stored either in ROM or within
the system, that’s used to simulate hardware functions.
Facsimile transmission (FAX): A process by which text and fixed graphic images are
optically scanned, converted into electronic signals, sent over communications lines, and
reproduced at a remote location.
FACT: Pre-COBOL business-oriented programming language.
Fall-soft system: A computer system that will continue to run despite localized system failure.
Fallback: A condition in which emergency (including manual) functions must be substituted for failed or
flawed system functions.
Fall-through execution: The content coupling that occurs when the execution of instructions continues
directly from one module into another without any termination procedures.
Fan-fold paper: Sheets of paper joined along-and folded on- perforations. Also called Z-fold paper.
Father: A higher-level node in a tree diagram.
Fax board: A circuit board that fits into a microcomputer’s expansion slot and acts as a specialized high-
speed modem.
FET: Acronym of field-effect transistor, a device that functions similarly to-but much faster than-the
vacuum tubes.
Fetch: To find the contents of a specific memory location and read it into the CPU.
Fiber optics: A technology based on the transmission of information by the modulation of light through
small-diameter glass fibers.

Field: Part of a data file or collection of data that can’t be broken down into smaller parts without losing
meaning. An example of a field would be LAST-NAME. A last name is a piece of data that can’t be
broken down into smaller components without losing meaning.
Figurative constant: In COBOL, a constant represented by a reserved word to which the compiler assigns
a specific value.
File: A collection of records of related type tat have a common use, function, or purpose. A computer file
is a method to store similar items on a computer.
File description: A statement as to the identification and physical structure of a file.
File dump: The operation that prints out the unformatted contents of a computer file.
File name: A name or symbol that identifies a particular file to the computer. A file name is composed of
two parts; the name followed by a period or dot and the extension. The first portion is used to identify the
contents or purpose of the file; the second denotes the type of file.
File server: The computer within a network that stores data and programs and allows other computers in
the network to access them.
Firmware: A program stored in permanent memory.
First-in-first-out (FIDFO): Phrase describing a certain processing order in a data queue.
Fixed disk: No removable magnetic disk, usually with a large capacity for storage.
Fixed-point arithmetic: Condition in computer calculations in which the user must keep track of the
decimal point.
Flag: A data item in a program used to signal the occurrence of a specific event or condition during
Flip-flop: A bitable circuit capable of storing one bit of information.
Floating-point arithmetic: Condition in computer calculation in which the computer keeps track of the
decimal point.
Floppy: Name given to removable diskettes because they are not hard.
Flowchart: A pictorial representation of a problem. A chart that defines steps to be taken to solve a
computer problem.
Flowmatic: Pre-COBOL business-oriented programming language.
Font (typeface): A set of letters, numbers, punctuation marks, and other symbols with a consistent
Footer: Standard material that repeats at the bottom of every text page.
FOR: The statement that opens a FOR/NEXT loop.
Forced execution: An option available on some COBOL compilers for forcing the execution of a program
in spite of syntactical error.
Foreground: A computer job that has a high priority. Any computer program that’s the primary user of
resources. The opposite of background.
Format: The layout or design of disk storage. Disks are “formatted” in a particular mapping sequence so
that a computer can read and write from the. To prepare a disk to be used by a computer.
Formula: An expression that instructs a spreadsheet program to perform calculations or other
manipulations on the contents of specified cells.
FOR/NEXT: A loop consisting of a fixed number of iterations.
FORTH: A contemporary programming language.
FORTRAN: A computer programming language specifically designed for mathematical and scientific
applications. A programming language that derives its name from the words FORmula TRANslation.
FREE: The BASIC function that returns the number of unused granules on a disk.
Free-form entry: Processing technique in which the user indicates the services and/or functions required.
Frequency: A measurement of the speed at which an electrical signal repeats itself. A standard measure
for the speed of a computer. The unit used to denote frequency is the hertz unit.
Friction feed: A method of feeding paper into a printer similar to that used by a typewriter where pressure
from the platen keeps the paper in place.
Full card: Term used to describe a computer card that’s large enough to require an entire expansion slot.
Full duplex: The transmission of data in both directions (send and receive) at the same time.
Fully inverted: A term describing a file or database that has become a collection of inverted lists of fields.
Function: A useable item of data in a table.
Functional cohesion: State of cohesion within a module in which all instructions contribute to the
performance of a single specific task.

Function keys: Special keys on a personal computer’s keyboard that reduce certain often=-used
commands to single keystrokes.


Gate: A circuit with one output and several inputs. In computer termin0ology, also
called logic circuit.
GENERATE: An I/O verb use din COBOL.
GET: The BASIC keyword that copies a record from the direct disk file and puts it into the buffer.
Gettering: The reduction of defects and impurities on a wafer through the use of chemicals, lasers, etc.
Gigabyte: One billion bytes.
GIGO: Garbage in, garbage out”, if you put incorrect data into a computer, you will take incorrect results
Glitch: A fluctuation in power or signal that can damage computer components and/or cause program
Global data: In COBOL, data defined in the DATA DIVISION.
GOSUB: Instruction to branch to a subroutine.
GOTO: A command used to coordinate branching.
GPIB: Pronounced gee-pib. Acronym for General Purpose Interface Bus, a computer code used to connect
analog devices to a computer.
Grandfather cycle: Period during which magnetic tape records are preserved.
Granule: One of the two elements into which each disk track is divided.
Graphics: Term used to refer to the ability of a computer to display charts, graphs, and pictures on a
monitor. The three major graphics adaptors are CGA, EGA, and VGA.
Graphics mode: The computer state in which the CRT screen is adjusted to accommodate graphics, video
games, etc.
Graphics package: Software that produces pictures and charts.
Group item: A data field made up of sub –fields that can be used separately.


Half adder: A circuit with two input and two output channels for binary signals.
Half card: A type of computer option card that’s small enough to take up only half of a full expansion slot.
Half duplex: Method of data transmission where signals travel in one direction at a time.
Halfword: A continuous sequence of bits or characters representing only half a computer word but
addressable as a unit.
Halt: Instruction to the computer to leave the Run mode.
Hamming code: An error correcting code system containing four information bits and
three check bits.
Handshake: Term given to the process that occurs when two or more computer devices acknowledge each
other. A series of control codes that are exchanged when computers are linked that determine
Hang-up: Malfunction of the central processor of a computer, characterized by an unplanned stop or delay
in the execution of a routine or the solution of a problem.
Hang up string: A set of codes that tells the modem when to hang up the phone.
Hard copy: Any form of permanent computer output that a user can read.
Hard disk: Name given to fixed or permanent disks because they are not flexible like diskettes.
Hard disk drive: A disk drive with vast, high-capacity, rigid magnetic disks.
Hardware: The physical parts of a computer. The parts of a computer that can be touched. Those parts of
a computer that are not user written. The opposite of software.

Hard-wired: Of a computer program or control system, permanently connected by the manufacturer and
hence un-programmable thereafter.
Hartley: A unit of computer information equal to 3.32 bits.
Hash: Noise consisting of electrical interference from a vibrator or commutator. Hashing function: An
algorithm that performs a mathematical calculation on a record key in order to convert it to a relative
address. Also called randomizing algorithm.
Hash total: The sum of the values within no significant data fields.
Hayes compatible: Modem compatible with the industry standard.
Head: The first cell on a list.
Header: Standard material that repeats at the top of every page of text.
Hertz: A unit of measure of frequency used to determine the speed of a computer. The larger the number
of hertz the faster the computer. Personal computers run at speeds measured in hertz.
Hexadecimal number system: A base-16 number system using symbols 0 through 0, and the letters A
through F.
Hidden file: A file, which is not displayed through the use of the standard directory command. A file
that’s not seen by the user and usually contains special system or program functions.
Hierarchy: A top-to-bottom multilevel organizational scheme.
High-level language: A computer programming language that when compiled expands into multiple
machine language instructions for each programming command entered. A computer programming
language resembles English language instructions; e.g. COBOL, FORTRAN.
Highlighting: Varying a CRT display for emphasis, as by blinking, changing colors underlining, etc.
HIPO: A hierarchy chart and IPO regarded as an interrelated whole.
History file: The chronological record of a master file.
HMOS: Extremely fast, high-performance silicon-gage technology based on MOS (metal-oxide
semiconductor) techniques.
Hold: A computer instruction ordering data to be called from but at the same time retained in storage.
Holerith card: The eighty-column punched card used to input data to a computer.
Holofiche memory: Memory containing millions of bits of data, much used for the
storage of medical records, credit information etc..
Home key: The key that returns the cursor to the upper left-hand screen position.
Host: The primary or controlling computer in a multiple-computer operation.
Hybrid computer: A computer having both analog and digital characteristics.


IBM card: The punched card used to input data into a computer.
IBM compatible (clone): A computer made to perform the same tasks, run the same programs, and accept
the same hardware components as an IBM Personal Computer.
IDCAMS: A COBOL system utility (MVS environment).
Identifier: A key name, as of a program, subroutine,etc.
Idle time: The interval between computer runs.
IEEE448: The Institute of Electrical and Electronics Engineers standard relative to the general-purpose
interfaces used to connect analog devices to computers.
IF: A word that poses a question concerning a condition.
IF/THEN: The statement used to check whether a certain condition is true or false.
Illegal: In computer parlance, a word descriptive of a character or combination of bits that the computer
rejects as invalid or inappropriate.
Imbedded sign¨A+ or –stored as a zone bit in an input data field.
Impact printer: A printer that makes images on paper by making physical contact with a ribbon and
paper. A printer that makes images on paper in the same method a typewriter would.
Implication: An IF/THEN logic operation.

Implied decimal point: The indication of the position of the decimal point in a numeric data field,
represented in COBOL by the symbol V.
Increment: To increase, as a number stored in a counter.
Index: A pointer to a file or program. A tool used to show the order items are stored on a computer.
Indexed file: A file that’s processed using pointers or indexes. A file that’s bit processed in a sequential
Inference engine: A set of programmed rules used as the basis of an expert system.
Infix notation: The natural form of expressing mathematical relationships, with the
operators (+, =, etc.) appearing between the symbols upon which they operate (thus,
Information: Data that’s meaningful to the user, Processed data.
Information services: Organizations that offer interactive networking to users who have terminals or
personal computers.
Inherited error: Computer error traceable to incorrect initial values.
Inhibiting input: A computer gate input capable of preventing any scheduled output.
Inhibition gate: A gate circuit used as a switch.
Inhibit pulse: A computer drive impulse that acts upon other drive impulses.
Initialization routine: The series of steps that prepares the computer to receive and process data.
Initialize: Top assign starting values to the variables in a given computer program.
INKEY$: The function that scans the keyboard to see which key is being pressed.
INPUT: A keyword that allows data to be entered while a program is running.
Input: Data that is entered into the system to be used by a program. Input can be from a disk, keyboard,
or other device.
Ins: Denotes the insert key on most computer keyboards. A key which allows the user to add letters,
numbers, or words into existing text.
Insert mode: When activated in word processing, all characters keyed in at the current cursor position
push any text to the right.
Insertion character: In COBOL, one of several special characters used to punctuate numeric data.
Instruction: A single command to a computer. A part of a computer program that performs a single
 Instruction counter: A multiple-bit register that keeps track of the address of the current instruction.
INT(eger): A computer function that supplies whole numbers, eliminating any decimal fractions.
Integer variable: In FORTRAN, a series of not more than six characters (plus special characters).
Integrated Circuit: An interconnected array of active and passive elements integrated with or on a
semiconductor substrate. Also called IC.
Integrated circuits: Small solid pieces of silicon containing the equivalent of many discrete electronic
Integrated software: A software package that combines more than one application.
Intelligent terminals: Terminals that can be adapted to communicate with a range of host computers.
Interactive: A method of processing that requires interaction with the user. The opposite of batch
Interface: A common link between system components. A card, board, or cable that links two hare ware
components together,. An electronic device that allows two or more system components to communicate.
Interlace: To assign successive storage numbers to physically separate storage locations of magnetic
media, thus reducing access time.
Interleaving: The insertion of segments of cone computer program in to another program.
Interlock: A protective feature designed to prevent unwarranted disturbance of or interference with
normal data processing or transmission procedures.
Internal arithmetic: Computations performed by the arithmetic unit of a computer.
Internal command: An instruction or command that’s loaded into memory when the operating system is
loaded and therefore does not have to be reloaded to be used. The DOS /DIR command is an example of
an internal command
Internal interrupt: A special control signal that diverts the attention of the computer to an extraordinary
even or set of circumstances.

Interpreter: A program that translates a high-level language program into machine executable code one
line at a time allowing for immediate execution of commands. BASIC is an example of a language that
uses an interpreter.
Interrecord gap: A blank space between records on magnetic media.
Interrupt: A deliberate break in the normal flow of a system or routine, usually accomplished by an
externally generated signal. To cause an interruption.
Involuntary interrupt: An interrupt, which though not caused by an object program, nevertheless affects
the operation of that program.
I/O: Abbreviation for Input/Output. A device or process whereby data is both read and written.
I/O bound: Descriptive of a condition that identifies the speed at which a computer can run a program
when that speed is limited by how fast data can enter and exit memory.
I/O buffer: A device that permits data word transfer to and from memory.
Ion implantation: A process related to the use of dopants. Also called ½
I/O Port: A channel connecting a computer to external input and/or output devices.
IOP selector: An input/output-processing unit for accomplishing bi-directional data transfer.
I/O scan: The time required for a processor to monitor all inputs and control all outputs.
I/O verbs: Input/Output verbs, such READ, WRITE, etc.
IPL: Initial Program Loader. A term used to refer to the process of starting a computer.
IPO: Acronym for input-process-output chart, a graphic aid much-used in COBOL.
Ips: Inches-per-second a measure of the speed at which magnetic tape moves.
ISAM: Acronym for indexed sequential access method, a file-management technique.
Iteration: Repetition. The number of iterations is the essence of a looping activity.


Jack: A socket to which circuit wires are connected at one end, and into which a plug is
inserted at the other.
Jitter: Short-term signal instability.
Job: A group of programs, instructions, or commands that are to be processed together that the computer
will treat as one unit.
Job control language (JCL): A language used to command the operating system of, usually, a mainframe
Job step: A combination of main program and one or more called programs under JCL control. Also
called run unit.
Josephson device: A digital LSI circuit that operates as a semiconductor at very low temperatures.
Joystick: A cursor-control device.
Jump: Instruction to a computer to shift operations from one program point to another.
Jumper-selectable: Describing a type of interrupt request that can be automatically generated by the
programmable peripheral interface.
Junction diode: A two-terminal semiconductor device whose key feature is that it conducts current more
easily in one direction that the other.
Justified: Spaces are inserted in each line of text so that every line is flush left and flush right.

Karnaugh map: A chart or table for simplifying networks of logical expressions.
Kernel: Lowest level of an operating system, at the heart of the “supervisory” function.
Key: A control field within a record. A keyboard button.
Keyed sequential access method (KSAM): A combination of file structure and interrelated library routines that
allows records to be read directly from a file.
Keyboard: The primary device for entering data and telling the computer what to do.
Key in: To input.

Keypad: Small keyboard with reduced number of keys.
Keypunch machine: A device for punching computer data holes in a card.
Keyword: Command to a computer, such as PRINT or SAVE.
Keyword-in-context (KWIC): An index listing available computer programs alphabetically.
KILL: BASIC command to delete.
Kilobytes: Unit for measuring computer memory. One kilobyte equals 1024 bytes or two to the tenth power.
Abbreviated as k or KB.
Kipp relay: a circuit with one stable and one unstable state. Also called monostable multivibrator.
Knowledge engineer: The expert whose input forms the base matter of an expert system.


Ladder diagram: The standard schematic for representing control logic relay systems.
LAN: Local Area Network. The physical linking of two or more computers was one act as a host for
programs and data and the others access the host as required. A method of attaching multiple computers
together over a small area directly with cables. A network in which the furthest points are no more than
five miles apart.
Language: In computer context, a carefully defined set of characters used to form works, symbols, etc.,
such as COBOL or FORTARAN.
Large-scale integration (LSI): Component density of more than n l00-per-chip.
Laser printers: Page printers in which laser beams reflected from spinning disks onto electrically charged
paper form electrostatic images that attract the oppositely charged particles of an ink toner.
Last-in-first-out (LIFO): Phrase describing a certain processing order in a stack data structure.
Latching: An arrangement whereby a circuit is held in position until some change in position is desired.
Also called locking.
Latency: The time required by a digital computer to deliver information from its memory.
Layout form: Worksheet used in programming and systems development.
LCD: Acronym for liquid crystal diode, an electronic device used to create alphanumeric displays in
computers and peripherals.
Leapfrog test: A program designed to uncover computer malfunction.
LED: Acronym for light-emitting diode, an electronic device used in computer monitoring and in
alphanumeric displays.
LEFT4: The BASIC function that extracts the leftmost characters from a string.
Leg: The vertical dimension of a structure chart.
LEN(gth): A function that examines a string or string variable and reports on the number of bytes it
LET: The statement that assigns a value to a variable.
Letter quality: Term used to denote a printer that can produce documents in a quality suitable for business
Library program: An organized set of computer programs, routines, special software, etc.
Light pen: A pen like device placed against a video screen in order to input or select data.
Light pipe: In fiber optic data transmission, an optical fiber that conducts light pulses.
Limiter: A transducer in which, above a certain value, the output doesn’t vary.
Limit test: A type of validating process.
LINE: A keyword that allows for the drawing of a straight line or rectangle.
Linear circuit: A circuit whose output is amplification or other variation of its input.
Line code: A single instruction to a computer to solve a specific problem.
LINE INPUT: A BASIC keyword that accepts an entire line of input from the keyboard.
Line number: The number that begins every BASIC statement, showing the order of statements within the
Line printer: A high-speed computer controlled printer capable of producing an entire line at one time.
Link: The field within a data item that specifies the location of the next logical element in a list.
Link bit: A one-bit diagnostic resister designed to indicate accumulator overflow.
LISP: Acronym for List Processor, a programming language.
LIST: A command to the computer to list a program beginning at a specified line.

LOAD: The command to bring a previously saved program from a diskette to RAM.
Load: To read a program from auxiliary storage into main memory prior to execution. To place a value on
a computer register.
Load and go: A computer operation in which pseudolanguage is directly converted to machine language.
Loader: A program for transferring information from off-line to on-line memory.
Lockout: An interval in the buffer cycle during which either the logic or arithmetic unit must cease
 Logging on (signing on): The process by which users of time-sharing systems identify themselves as
being authorized to gain access.
Logic: In computer terminology, the mathematical adaptation of formal logic into relationships that can be
expressed by switching circuits and/or gates.
Logical cohesion: The low-level cohesion that results when module elements are related through
superficial logic only. Also called spaghetti programming.
Logical operator: In a COBOL decision statement, an AND, OR, NOR, etc.
Logic error: Error due to faulty reasoning.
Logic gate: An electrical component capable of performing a logical operation.
LOGO: A programming language.
Look ahead: A CPU feature that permits the masking of an interrupt request until after the next instruction
has been completed.
Loop: A series of statements or instructions in a computer program that are repeated. A look can be
executed any number of ties and is one of the features that makes a computer handle repetitive tasks easily.
Low-level language: A machine-oriented language, such as Assembler.
LPT1: Name commonly given to a printer attached to a personal computer. Name used to refer to the first
printer attached to a computer.
LSI: Acronym for large-scale integration, the accumulations of a large number of circuits on a single
semiconductor chip.

Machine language: A programming language that’s unique to each type of computer
where the commands are composed of strings of ones and zeros.
Machine reel: A tape-drive reel used to hold unwound tape. Also called take-up reel.
Macro: A set of instructions that performs a single task grouped together that can be reused in many
Macro assembler: A code-simplification feature usually located in RAM.
Macro facility: In FORTRAN programs, an assembler feature that facilitates the modification of an object
tape of FORTRAN.
Magnetic disks: Oxide-coated hard metal or “floppy” plastic platters for recording computer data.
Magnetic tape: Oxide-coated Mylar plastic tape for recording computer data.
Mailbox: A set of locations in a common RAM storage area.
Mail merge: A word-processing feature that allows the user to merge a file of names from a mailing list
with the text of a form letter.
Mainframe: A large-scale, high-speed computer that usually serves hundreds of users at the same time ad
is principally used by large organizations and government agencies.
Main memory: A device connected to the computer processor unit that supports the handling of data by
the control unit or ALU.
Main program: Calling program.
Major key: The name of the highest order of precedence of two or more record keys.
Marker: A symbol indicating the beginning or end of a specific set of data.
Masked: A central processing unit, protected against certain types of interruptions.0master: In a multi
computer configuration, the dominant unit that controls, schedules, and transmits tasks to its “slave”
Master file: A permanent file of computer data.
Math chips: Processors that perform basic arithmetic, logarithmic, etc., functions for a microcomputer.

Matrix: A system for determining the spatial location of points by reference to horizontal and vertical
Mean-time-to-failure (MTTF): The average time a system or system component operates before failing.
ME code: The instructions to a computer printer in a merge operation.
Megabyte: Equal to l, 048,576 bytes or l000 k or two to the twentieth power. Abbreviated as M or Mb.
MEM: BASIC function that returns the number of free bytes in RAM.
Memory: The part of a computer that stores information while a program is executing. Memory is a
temporary storage medium and is erased when the power is turned off.
Memory bus: The bus by means of which the CPU communicates with memory and I/O devices. Also
called I/O bus.
Menu: A program which lists possible options that a user can choose. The user picks the item he wishes,
enters the number that corresponds with the selection, and the desired program executes.
Merging: A computer technique for personalizing letters or other documents through recoding.
Micro: A single, brief command to the computer.
Microcomputer: A computer designed for personal or small business use with circuits contained in chip
form. Most microcomputers are small enough to be kept on a desktop.
Micro controller: A micro programmed machine; a microprocessor; or a microcomputer used in a control
Microfiche: A sheet of film used for recording and storing micro images.
Micro program: A program of computer instructions that doesn’t reference main memory.
Microsecond: One millionth of a second.
MICR scans: Sensing of the characters, marks, or codes printed in magnetic ink on bank drafts.
MID$: A BASIC function that accesses the character sin the middle of string.
Minicomputer: A computer system, which is larger in memory and faster than a single
use microcomputer but smaller in memory and slower than a mainframe.
Minimal recalculation: That technique of spreadsheet editing in which the revision of values and/or figures
is kept to a minimum.
Minor key: Any record key other than that used in sorting records for sequential files.
Mnemonics: l. The art of improving the efficiency of the memory. 2. Words specifically designed to job
the memory by suggestion/recollection.
Mode: The status of a device as graphics mode, for example.
Modem: A device used to transmit and receive data over a telephone line. A device named from the
words Modulate DEModulate.
Modula 2: A programming language.
Modulation: The conversion digital signals into analog signals.
Module: A relatively independent group of related program statements that can safely be treated as one
Monitor: A high-resolution video screen.
Monochrome display: A display or monitor on which data appears in only one color. Monochrome
displays are usually available in green or amber.
Monostable multivibrator: A circuit with one stable and one unstable state. Also called Kipp relay.
MOS: Acronym for metal-oxide semiconductor, the device that forms the gate structure for an FET.
Motherboard: The piece of computer hardware that all the computer cards plug into. The main board in a
Mouse: An input device consisting of a small plastic box with either wheels or a ball roller that produces
electrical pulses when rolled on a flat surface; it allows the user to manipulate objects on the display screen.
MOVE: An I/O verb used in COBOL to shift data from one location to another.
Moving-domain memory (MOD): A small, fast, easily fabricated memory.
MP/M (Multiprogramming Control Program for Microprocessors): An operating system providing
multiterminal access, with multiprogramming at each terminal.
MPU: Acronym for Microprocesing unit.
MS-DOS: Microsoft-Disk Operating System. A version of DOS written by the Microsoft Company.
Multilevel control break: Phase describing a condition of a COBOL problem in which two or more
variables are involved.
Multilist: A linear link list in which more than one set of attribute values are linked.

Multipass program: A computer program requiring a series of intermediate outputs that need additional
processing in order to reach the desired end result.
Multiplexing: In communications, the concurrent transmission of more than one information stream on a
single channel.
Multiprocessing: The ability of a computer with more than one CPU to run several programs
Multiprogramming: The concurrent time-sharing of computer components by a number of unrelated
Multitasking: The ability of an operating system to run more than one program currently by rapidly
switching between them.
MUMPS: A text-oriented programming language much used in hospital applications.

Named constant: In COBOL, a constant with a specific function within a program.
NAND: A logic operator that’s the invert of AND; a negated AND.
Nanosecond: One billionth of a second.
Narrowband channels: Communications pathways with a bandwidth of less than 3000 hertz and
transmission rate between 5 and 30 characters-per-second.
Near letter quality: A term used to describe a printer that produces documents that have a quality of print
very close to letter quality. An abbreviated as NLQ.
Nesistor: A transistor that’s dependent upon a bipolar field effect.
Nested IF test: A series of condition tests involving two or more levels of selection statements.
Nested loop: A loop within a loop.
Network: A group or series of computers interconnected where one computer will store and maintain the
programs and data and the others will access it when required.
Network data structure: A data structure in which any element may access any other element.
NEW: The BASIC command to erase RAM.
NEXT: The statement concluding a FOR/NEXT loop.
Nibble: Four bits; half a byte.
Node: A single entity in a network.
Noise: Electrical interference or static that can occur on an electrical power line or a communications line.
No-op Instruction: An instruction to be computer to do nothing except process the next instruction in
NOR gate: A circuit whose single output is energized only if all inputs are zero.
NOT: A logical operator that causes a relation to be not true.
Number crunching: Computer processing that involves extensive arithmetic operations.
Numeric: Describing data consisting only of the digits O-9, indicated in COBOL by the symbol 9.
Numeric Lock key: A keyboard key used in conjunction with numbers on a screen. It is also called Num
Lock key.
Numeric variable: A field that can contain only numbers during program execution.

Object code: Name given to computer programs that have been compiled or translated into executable
Octal: Base-8 shorthand computer number system.
Odd-even check: An automatic computer check in which an extra digit is carried along with each word.
Office automation: The application of new electronic, telecommunications, and computer technology in
the white-collar workplace.
Off-line: Not directly connected to the computer.
One-way list: A linked linear list whose data items are connected by pointers within a single sequence.
On-line: Directly connected to the computer.

Op code: Operation code-the portion of machine-language instructions that specifies the operation to be
OPEN: l. An I/O verb in COBOL 2. A BASIC keyword that permits access to a disk file.
Operand: The name of a data location.
Operating system: A set of programs or instructions that make a computer perform assigned tasks.
Operating systems are provided with most computers. The standard operating system for personal
computers is MS-DOS.
Operator: A symbol, such * or +, that tells a computer to perform an operation.
OR: A logical operator that’s used in a comparison of two or more values. If the action indicated in the
comparison is to occur, only one portion of the comparison need be true.
Order of arithmetic operations: The pre-determined order in which arithmetic functions are always
executed under the COBOL COMPUTE command.
OS/2: Short for Operating System 2, a new operating system designed by IBM to be used with PS/2
personal computers.
Oscillator: A device that provides alternating current of any frequency, sustained in a circuit by a vacuum
tube or transistor.
Output: Information that’s obtained from a computer. Output may be displayed on the CRT, produced as
hard copy by the printer, or stored.
Output enable: The signal that controls the output.
Overlay: A technique for bringing routines into high-speed memory during processing.
Overwrite: To place information in a location while destroying the information previously stored there.


Pack: The combination of several field of information into one machine word.
Packaged: A general, prewritten, and debugged software program.
Page: A 4096 byte segment of a computer program that’s read and processed at one time. A group of
consecutive bytes of storage that’s processed as a unit.
Page layout package: Software that allows the user to integrate graphics and text into a single document.
Page Up/Page Down keys: The keys that shift text on a monitor from page to page.
PAINT: A BASIC instruction that allows for the coloring in of a shape on or a section of the screen.
Paper tape: Strips of paper that have been punched, printed, or otherwise provided with computer-readable
Paragraph: In COBOL, one or more sentences constituting a logical processing unit.
Parallel: A method of attachment where each wire is directly connected to allow for simultaneous
transmission. Refers to the method of attaching printers to a personal computer.
Parameter: A portion of a command or instruction that provides specifics on the scope, range, and
performance of the command. For example, the copy command requires two parameters, the name and
location of the source of the copy and the name and location of the target of the copy.
Parametron: A device composed of two stable states of oscillation, and able to store one binary digit.
Parent: A higher-level node in a data structure.
Parity: A system designed to check for integrity in transmitted data and to correct errors that may occur.
Parity bit: A binary digit that’s used in error checking.
Part: A command which causes the read/write heads of a fixed drive to stop over an unused portion of the
disk before turning off the power or moving the computer. The park command is designed to help prevent
data loss on fixed disks and protect the drive from damage during transportation.
Partial RAM: A memory chip containing some unusable bit locations.
Partition: A segment of a unit. A part of a disk dedicated to a particular function; e.g., storage of an
operating system.
PASCAL: A high-level programming language designed to teach structure programming. A language
used in scientific and mathematical applications.
Passivation: The formation of an insulating layer over a semiconductor surface in order to protect it from
moisture, contaminants, etc.

Password: A security tool that allows only those who know a preset code to enter or use a computer or
Patch: A portion of code inserted in a program to modify or debug it.
Path: A list of directories and subdirectories to be searched when a command or program is called. A
command used to designate where the computer should look for a program or file stored on disk.
Pause: A temporary stop inserted in a program in order to give the user reading time.
PC: 1. Personal Computer. 2. Printed Circuit.
PCLS: The BASIC screen-clearing keyword.
PEEK: A computer function that permits the examination of a particular memory location.
PERFORM: A COBOL verb used to cause the execution of a logic module not in line.
Peripheral: A piece of equipment that’s separate from the CPU but under the control of the CPU.
Personal computer: A microcomputer that’s predominantly designed for personal use or for small
businesses. Abbreviated as PC.
Personal identification number (PIN): An entry control code number for accessing an automatic teller
PERT: Acronym for Program Evaluation and Review Technique, a critical-path analysis using computer
Phase logic: Means of transferring computer action from one operational phase to another.
Phase shift: The time difference between the input and output signals of system.
Photodiode: A two-electrode semiconductor device made up of a photo conducting cell and a junction
Photo resist: Masking material used in the etching of semiconductor devices.
Pico second: One trillionth of a second
PILOT: A programming language:
PIN: Personal identification number.
Pin feed: A method for feeding paper into a printer using tiny holes on both edges of the paper and gears
on the printer that pulls the paper through. Same as tractor feed.
Pipeline computer: A computer that executes serial programs only.
Pipelining: The overlapping of the fetch and execute cycles when a processor.
Pitch: The number of characters and spaces-per-inch.
Pixel: Abbreviation for Picture Element. The name given to the tiny dots of light that make up the display
on a computer monitor.
PL/l: A general-purpose high level programming language.
PLA: Acronym for programmed logic array, a combination logic device sometimes used as an alternative
to ROM.
PLAY: A BASIC: keyword that allows for the sounding of notes at a specific pitch, volume, and length.
PL/M: A powerful high-level algorithmic programming language.
PLMX: A universal high-level microprocessor language.
Plotter: An output device that can chart pictures, graphs, and drawings, used extensively in drafting and
CAD operations.
Plug board: A removable computer board equipped with many electrical terminals into which connecting
cords can be inserted.
PMODE: The BASIC command that establishes degree of resolution, number of pages, and number of
colors in the graphics mode.
Point-of-sale (POS) systems: One or more intelligent terminals located at check-out counter sin stores
used to pass inventory information to the store’s central computer.
POKE: A computer operation that loads a value into a specific memory location.
Polling: A technique used by a multiprocessor to identify the source of an interrupt request.
Port: A point on a computer to allow for the attaching of a peripheral device. A place on a device or
computer to plug in a cable. (Where the printer plugs into the computer.)
Portability: The degree to which a module can be used with other programs.
Post byte: A byte, following the op code that identifies the register(s) to be used by the instruction.
Post mortem: A diagnostic routine for pinpointing the cause of a computer error or malfunction.
Power-fall logic: Logic circuitry that protects a system in the event of power failure.
Power supply: A computer’s source of electrical power; it contains transformer to lower and regulate the
voltage level of electricity provided to the computer.

Power up: The orderly startup of a computer system.
PPM: Abbreviation for Pages-Per-Minute. The unit of measurement used to denote the speed of a printer.
Pages-Per Minute is used with printers that print an entire page at a time especially lasers printers.
Precondition: The preliminary logic instruction that precedes an output instruction.
Primary key: A key that establishes the most important reference for a given data item.
PRINT: A command to the computer to display information on the screen.
Printed circuit (PC): An electrical circuit imprinted on plastic.
Printer: A piece of peripheral equipment that produces hard copy of text and graphics.
Printer spacing chart: A special form used to design the appearance of output prior to coding.
Print head: That part of a printer that actually makes contact with the ribbon and paper to form an image.
Print layout: A diagram showing the planned format and content of a printed report.
Printout: A printed copy of computer produced data.
Print Screen key: Keyboard key used in conjunction with the Control or Shift key.
PRINT USING: A BASIC command for formatting numeric output.
Print zone: Division of the screen into approximately 16 positions.
Procedural cohesion: Cohesion that results when the primary relationship among the elements within a
module is the control-flow sequence.
Procedure: An operation that’s performed in order to reach an objective.
Processing box: A flowchart symbol describing the steps (such as arithmetic, for example) that will take
place within a computer program.
Processing control: A routine that permits or prohibits the processing of records on the basis of data
content and format.
Processor: 1. A digital device capable of performing certain operations on a digital representation of data.
2. A computer program that performs certain functions, such as compiling or assembling, for a specific
programming language.
Program: A series of instructing or commands grouped together which when executed on a computer
perform a complete task.
Program counter (PC): A unit that contains the address of the next instruction byte to be fetched from
Program design aid: A tool, such as a pseudocode or flowchart, useful in creating a computer program.
Program development process: A series of steps to be followed in creating a successful computer program.
Programmable logic: The totality of devices and systems capable of solving problems ranging from the
simple to the extremely complex.
Programmer: An individual who writes the instructions for the computer using computer language.
Programming language: A set of rules and meanings used to write computer programs. A method to
express computer programs into English like statements.
Program requirements: The essentials of a finished and effective computer program.
Program status word (PSW): A computer word containing information used in interrupt processing (and
Progressive overflow: A method for handling synonyms, in which the synonyms for a given record are
written in the next available position after the record position. Also called open addressing.
PROM: Acronym for programmable ROM, a read-only memory that can be altered by the user.
Prompt: A line, symbol, sentence, or group of words which requests input from a user.
Protectable memory: Memory that doesn’t fail because of power loss.
Protocol: Term used to describe the rules used for the transmission of data between computers especially
in telecommunications.
Prototype: The working model of some putative entity, as, for example, a proposed computer program.
PSET: A keyword used with graphics displays.
Pseudocode: A problem-solving technique based on a series of numbered steps.
Pulsed logic: A signal modification that produces output independently of input signal duration. Also
called one-shot logic.
Purse generator: A generator specially designed to produce pulses for purposes of special timing or
gating in a digital computer.
Punched card: A thin cardboard card pierced with holes in a definite pattern that represents data.
Purging: Removing a record from a file, and then closing up the blank created thereby.
Pushdown list: A stack of items maintained in LIFO order.

Qualifier: In COBOL, a word added (with IN or OF) to a name in order to make it unique.
Quanta: In a time-sharing system, the units of processing time allocated to a given program during its turn
in the computer.
Quantitative information: In a report, the variable content or value of a detail line.
Query: A specific request for information, instructions, etc., during computer operation.
Query language: A computer language resembling English, designed to allow non-programmers to
address the computer.
Queue: A structure used to store objects or commands in which inputting and outputting may occur only
from an end of the queue. Queues are used frequently with printers. A file is sent to a print queue and at
the proper time is printed.
Quiescing: Stoppage of a multi programmed system.
Quit: Command used to cease operations connected to a spreadsheet program.

RAM: Acronym for Random-Access Memory. That memory which is available to the
user for programs and data. This type of memory is deleted when the computer is turned
Random access: direct access.
Random file: A computer file in which the records are not arranged in any logical order
or sequence.
Raster: The exposed area of a CRT screen.
Raster scans: A technique for presenting images on a video screen by illuminating a
series of dots.
Reactive mode: The condition existing between a computer and one or more remote
terminals in which each entry causes a computer action.
READ: 1. An I/O verb used in COBOL. 2. The BASIC commands that assigns values to
numeric or string variables.
Read in: To place data in storage at a specified address.
Readout: A technique by means of which a computer furnishes processed information in
the form of a visual display, punched tape, etc.
Read/write head: The part of a disk drive that actually stores and retrieves data from a
Real-time processing: The immediate processing of data by a computer.
Reboot: To turn a computer off and then on.
Record: A collection of data fields that have a similar purpose or meaning. Fields
containing name, address, and zip code might all be in the same record due to their
relationship to each other.
Recoverable error: An error condition in the computer that doesn’t interfere with
continued program execution.
Rectifier: A device for converting alternating current into direct current.
Recursion: Continuous repetition of the same operation or series of operations.
REDEFINE: In COBOL, an instruction to the compiler to rename-not replace-an
existing area.

Red-tape operation: A data-processing operation, which, though necessary, doesn’t
contribute to the end result of the program.
Reentrant code: A code executed simultaneously by more than one software module.
Register: Word of fast memory used for temporary data storage.
Relational database: A collection of files with different record structures, but with at
least one field that’s duplicated in another file.
Relational operator: A symbol, such as=, that represents the comparison of two values.
Relational test: In a COBOL decision statement, a condition tests involving a logical
comparison of two data items.
Relative file: A file in which the address of a record is expressed in terms of its position
relative to the rest records. Also called direct file.
Relay: An electromechanical device in which contacts are opened or closed by circuit
REM(ark): A symbol that introduces an explanatory comment on a program.
Remote: A terminal or computer that’s in another location that can be accessed via
communications lines.
Rename: A command issued to alter a file name.
RENUM(ber): A BASIC command for resetting line numbers.
Replace: An instruction to a telecommunications program to replace existing data in the
capture file with newly downloaded data./
Replacement character: In COBOL, a character that substitutes for a leading, no
significant zero in a numeric data field.
REPORTWRITER: A special COBOL feature designed specifically for handling the
writing of reports.
Rerun point: A reselected point in a computer program at which a program may resume
(rather than having to return to the beginning of the program). Rescue dump: A disk or
tape recording of the entire memory, made as a precaution against power failure or other
mishap. Also called R dump.
Reserved word: In COBOL, a word with a special, predefined meaning and strictly
limited applications.
Reset: To set all hardware and software to their original configurations.
Resident macro assembler: The feature that enables a computer user to translate
assembly-language programs into machine-language instructions.
Resolution: Quality of a displayed image, as determined by the number or pixels per
square inch on the screen.
Response time: The interval between an interrupt and the initiation of the interrupt
handling subroutine.
RESTORE: A BASIC command that resets an internal pointer to the beginning of the
DATA statements.
RETURN: An instruction to go back to the caller of the subroutine.
Return from Interrupt (RTI): An instruction to the computer to bring registers contents
back from the sacks.
Return key: Enter key.
Return stack: The area of main storage where instruction addresses are stored.
REWRITE: An I/O verb used in COBOL.
RIGHT$: The BASIC function that accesses the rightmost characters in a string.

Rigid disk: A hard metal platter for recording computer programs and data.
RJE: Acronym for emote Job Entry, a feature that allows a number of systems to share
the resources of a batch-oriented computer.
RND: A function that generates a range of random numbers without any apparent
pattern or significance.
Robotics: The use of automated computer controlled devices to perform functions in,
usually, industrial environments.
Rolling total: A feature of a control break program that provides for transferring an
accumulated total to the next higher summary level.
ROM: Acronym for Read-Only Memory. That memory which is specifically allocated
tot the system functions of a computer. This type of memory may be read and used but
not changed or deleted by the user. ROM is not deleted when the computer is turned off.
Root director: The list of files, documents, or programs in the highest-level directory.
The root directory can also contain other directories called subdirectories.
Rooted node: Describing tree data structure in which one node is super ordinate to all
Root node: The highest-level super ordinate node in a tree data structure.
Routine: A computer program subdivision that directs the computer to perform a certain
RS-232: The EIA standard connector used on most computers for the attachment of
peripheral equipment.
RUN: A command to the computer to executive a program.
Run data: The day on which a report is prepared.
Run phase: The execution of a target program after compilation.

Sandwich: A combination of individual chips.
Satellite computer: A computer used to relieve a central processing unit of certain basic, time-consuming
SAVE: An instruction to the computer to record a program (with variables) on disk, cassette, or other
Scan: To search an array, as to determine the frequency of a certain character.
Scan rate: The frequency with which data are compared or read.
Scanner: A device used to convert graphs, charts, pictures, or printed text into a form that can be stored
and used by a computer. A device, which digitizes information.
Scatter loading: A technique of loading main memory in such a way that, although each program segment
occupies its own memory area, these are not necessarily adjacent.
Schottky barrier diode: A high-frequency junction diode used for ultra-high-speed switching.
Scope terminator: In COBOL, a verb used to indicate where another verb’s scope ends.
Scratchpad: CPU memory.
SCREEN: A BASIC statement relative to color (graphics mode).
Scrolling: The ability to move lines of text up or down on a display screen.
Scroll Lock key: A keyboard key used for scanning.
SEARCH: A COBOL verb used with tables of values.
Search and replace: A word-processing feature that lets the user search for a character, word, or phrase
and replace it with something else.
Secondary memory: Memory usually of large capacity but with longer access time.
Section: A major unit within a division of a COBOL program.

Sector: Name given to the divisions of the concentric rings on a disk that are used to store information
Seek: A computer process for locating specific data in random access storage.
SELECT: In COBOL, a clause used in file control.
Selection control structure: A programming technique that requires the computer to make a choice.
Self-adapting: The ability to change performance characteristics in response to environmental variations.
Self-test: A set of procedures a computer or peripheral performs to determine if it’s functioning properly.
A method that allows the user to determine if a problem is with a particular device or with the way several
devices are attached to each other.
Semaphore: A flip-flop used to synchronize data transfer between a computer and a peripheral device.
Semiconductor: 1. A material with an electrical conductivity between that of a metal and that of an
insulator. 2. An electronic device composed, in part, of semiconductor materials.
Semi modular computer: A computer with a single computer board, but with some empty slots..
Sentence: A complete, syntactically correct COBOL statement terminated by a period.
Sentinel value: A value higher than any real value in a file, serving as an end of file indicator.
Sequence control structure: A programming technique spelling out the step-by-step behavior rewired in
order to solve a given problem.
Sequential file: A file that is processed one record after another in the order they occur.
Serial: A method of transmitting data by sending one part after another over a line. A method of attaching
printers to a personal computer.
Servomechanism: A closed-cycle system in which a small input power controls a much larger output
SET: 1. A COBOL verb used in manipulating indexes. 2. A BASIC keyword that displays a large pixel
(text mode).
SGN: A function used to determine if a given value is positive, negative, or zero.
Shannon equation: An equation that places a theoretical limit on the rate of transmission of binary digits.
Shared-bus system: A technique by means of which free access is provided to both memory and
peripheral devices.
Sheet feed: To place paper into a printer one sheet at a time either manually or automatically through the
use of a feeding device.
Shift key: A keyboard device for printing capital letters.
Short-haul modem: A device for transmitting data over short distances.
Signature analysis: The conversion, for testing purposes, of bit patterns into their alphanumeric
Significant digit: A digit that contributes to the precision of a number.
Signing on: As same as logging on.
Sign test: In a COBOL selection statement, a test for determining the condition of the algebraic sign of a
numeric field.
Simplex: A data communications method that allows for one-way transmission at a time either sending or
Single-board computer: An inexpensive computer consisting of one circuit board.
Single-pass program: A computer program that produces the desired end result in one run.
Single-sided diskette: A diskette that’s designed to record data on one side only.
Skeleton programming: The use of pre-existing program components to shorten the program-writing
Skip bus: A central processor bus shared by a number of I/O interfaces.
Skip instruction: A blank instruction, which the computer “skips” as it, proceeds to the next.
Slave: A unit of electronic gear controlled by signals from some type of super ordinate, or “master”,
Slicing: Breaking a string value into sections. Also called sub stringing.
Smoke text: An equipment test for possible overheating.
SNOBOL: Acronym for String-Oriented Symbolic Language, a programming language.
Soft error: Occasional random loss of data for reasons unknown.
Software: Controlling programs that tell the hardware comprising a computer system what to do.
Solid-state: Electronic components composed of or operating within solid materials (as distinct from
vacuum and gas tubes.)

SORT: A COBOL verb use to arrange data in some predetermined order or sequence.
Sorting: The sequencing of input data into alphabetic or numeric order.
SOS: Acronym for silicon-on-sapphire, a semiconductor manufacturing technology combining those two
materials (the sapphire being synthetic, however).
SOUND: A BASIC keyword that outputs an audible tone.
Source: The origin of information or data. The disk that contains the original item that’s to be copied.
Source code: A program that hasn’t been compiled. A program still in high-level language.
Spacebar: A computer keyboard device similar in function to a typewriter spacebar.
Spanned record: A complete record stored on two tracks of a disk.
Spelling checker: A word-processing feature that checks every word in a document against a built-in-
spelling dictionary and flags misspelled words for the user.
Spikes: Power fluctuations fatal to unsaved data.
Spin block: The loop created when a process continues to check the status of a flag or status bit while
waiting for an event to occur.
Spooling: The temporary storage of data on disk or tape files.
Spreadsheet: Worksheet on which financial statements, such as balance sheets, income statements, and
sales reports, are laid out in columns and rows..
Stamp coupling: A form of coupling in which two or more modules share the use of local data.
Stand-alone program: A computer program operating independently of system control.
Statement: A single command with parameters in a computer program.
State switcher: A solid-state power loss-sensing circuit that switches from line power to inverter output in
the event of power failure.
Static memory: A memory device containing no moving parts.
Status line: In spread sheeting, the place on the screen where the typed data appears before moving to the
assigned cell.
Status word: A word necessary to resume computer processing after the servicing of an interrupt.
STEP: A word used to increment the control variable in a FOR/NEXT loop by a number other than l.
Stepwise refinement: The top-down approach used in decomposing a problem in order to determine how
to solve it.
STOP: A command to terminate the execution of a program.
Stop bit: A binary digit that’s used to signal the end of transmission. A control character used in computer
STOP RUN: The COBOL version of the STOP command.
STR$: The function that converts the definition of a numeric to a string.
STRESS: Acronym for Structural Engineering Systems Solver, a programming language used in civil
engineering applications.
Stress testing: A testing technique that probes the outer limits of program or system performance.
String: A group of characters funct9oning as a unit.
STRING$: The BASIC function that permits the repetition of specific characters, as required.
String variable: A field containing letters, numbers, or special characters.
Stripe card: A plastic card containing a stripe of computer-readable magnetic tape.
Structured programming: A method of programming that advocates the standardization of coding which
includes the use of looping structures and conditionals rather than GOTO commands. Rules and
conventions used by most professional programmers.
STRUDL: Acronym for structural design language, a programming language used in civil engineering
Stub: A subroutine that can be branched to for debugging purposes.
Subdirectories: Subdivisions of root directories.
Subprogram: A program segment with specific functions within the overall program.
Subroutine: A subsidiary program available as needed during the execution of the main program.
Subsection: A program function listed on a computer menu.
Suite: A collection of separate but interrelated programs designed to run consecutively in order to
accomplish a specific task.
Supercomputer: A theoretical machine of the future that will include 300,000 circuits.
Surge: A sudden jump in electrical current. Power surges can damage a computer and cause erratic

Surge protector: A device that protects electrical equipment from sudden jumps in electrical current
Switch: A program flag that controls the path a given record will follow.
Synchronous: Transmission of data at a fixed rate so that no start and stop bits are needed.
Abbreviated as SYNCH.
Synonym: A record that produces a record slot collision because it hashes to an already occupied address
on a disk.
Syntactical error: Misuse of programming language.
Syntax: The set of rules that a high-level language used to define how instructions would be coded.
Systems analysis: The practice of evaluating an existing system to see how it works and how well it meets
the users’ needs.
Systems analysts: Professionals whose basic responsibility consists of evaluating existing manual and
computer systems and planning new ones by translating users’ needs into technical specifications.
Systems design: The process of planning a new system based on the findings from a system analysis.
System unit: The part of a personal computer that contains the central processing unit, memory, and
special function cards.

Tab key: The key governing the physical parameters of the computer screen.
Table: As same as array.
Tail: The final cell in a linear list.
Take-up reel: As same as machine reel.
Talking terminal: A computer-independent dial-up device that can be connected to a computer.
Tape drive: A machine that reads from and writes onto reels of magnetic tape.
Target: The destination of a copy command. The disk to which a file or program is being copied to.
Task queue: The queue containing all task control blocks in a given system.
Telecommuting: Working at home using a computer linked to an office via telecommunications lines.
Teleschooling: Computer-assisted education.
Template: In data-processing context, a plastic device used by programmers and task analysts in designing
Temporal cohesion: Cohesion resulting from time-related relationships within a module.
Terminal: 1, A device, with keyboard and display unit, used to communicate with a computer.. 2. An oval
flowchart symbol indicating the beginning or end of a program.
Terminal node: In a tree data structure, a node with no descendant. Also called leaf.
Test strobe: A clock that’s independent of data patterns, and is capable of enabling logic in a device or
Text mode: The computer state in which the CRT screen is adjusted to display information as on a book
THEN: Word used in an IF/THEN statement to elicit instructions in the even the IF comparison is true.
Thermistor: A solid-state semiconductor whose electrical resistance varies with variation in temperature.
Three-state logic: A logic family that may be in one of three-rather than the usual two states: high, low, or
Throughout: The volume of processing a computer system can handle in a given period of time.
Thyristor: An electronic switching device activated by rapid pulses of control current.
Time gate: A transducer that outputs only at specific prearranged intervals.
Time-shared BASIC: A conversational computer language affording easy computer access to a large
number of persons.
Time slice: The specific interval during which a job can run without risk of preemption.
TO: The word used in a FOR/ TO statement to assign limits to a control variable.
Touch screen: A special monitor screen that reacts to finger pressure.
TRACE program: A program that instructs the CPU to display the contents of any combination of
registers or memory throughout the execution of the program being developed.
Tracks: The concentric rings on a disk that is used to store data magnetically.
Trailer record: The final record in an input file, indicating that all previous records have been processed.

Transaction: An exchange between a computer and a user.
Transaction file: A set of records containing the information about a specific activity.
Transaction-oriented processing: As same as real-time processing.
Transceiver: A device capable of both transmitting and receiving signals..
Transducer: A device by means of which energy can be made to flow from one or more transmission
systems to one or more other transmission systems.
Transfer: Computer instruction that shifts control from one part of a program to another.
Transistor: An electronic device made of solid material those functions like a vacuum tube.
Transistor: A program for transforming code in high-level programming language into machine language.
Transmitter card: A means of converting parallel digital data into a asynchronous serial code.
Trap: An interrupt generated by software, or through programming error.
Tree: A graph data structure.
TROFF: The BASIC command to turn off the tracing feature.
TRON: A BASIC command that allows the programmer to trace the program during execution for
debugging purposes.
Truncation: The dropping of excess characters when a data item is moved to a receiving field with
insufficient room to hold the item as constituted.
TTL: Acronym for transistor-transistor logic, a relatively inexpensive-and the standard-form of bipolar
circuit logic.
Turnkey: A computer console containing a single control, turned on and off with a key.
Tutorials: Computer-provided learning assists.
Two-way list: A link linear lists incorporating two pointers per cell.
Type: A command to the computer to display text-file contents.


Unbundling: The setting of prices for software and services irrespective of hardware prices.
Unconditional jump: A computer instruction that interrupts normal operation to specify an address from
which the next instruction must be taken.
Underflow: The condition that results when a machine computation is too small to be stored.
UNIVAC l: The first commercially produced computer.
Universal synchronous/asynchronous receiver/transmitter (USART): A chip used as a peripheral
device in most serial data-transmission technologies.
Unpack: To separate the various items of information for a computer provided into distinct machine
words of a cycle.
Unwind: To code explicitly all the operations of a cycle.
UPC: Acronym for Universal Product Code., the standard bar code of the food industry.
Updating: The modification of master files to reflect additions and deletions.
Upgrade: To add components to a computer to give it greater capacity, speed or capabilities.
Upload: To copy a file from a personal computer to a host computer usually a mainframe. Upload is used
extensively in networks.
Up time: The period during which a computer is either operating or available for operation
User-friendly: The characteristic of software that makes it easy to use; instructions and answers to
questions are built-in to guide the user..
User group: A group of computer users with similar interests and computers formed for the sharing of
information, programs, and techniques.
Utilities: Software programs that assist in the operation of a computer.

VAB: Acronym for voice answer back, the capability of a computer system to respond to inquires from
telephone-tape terminals.

Vacuum tube: An electronic switch that sends electrons over a finite distance in a matter of microseconds;
employed in the first electronic computers.
VAL(ue): A function that converts string definition to a numeric.
Validation: The verification, through checks, of the accuracy and completeness of fields, records, etc.
Variable: A symbol used to represent a value or group of values within a computer program that can
change as the program is executing.
Vector: A quantity with both magnitude and direction.
Vector interrupt: An internal or external interrupt having its own uniquely recognizable address.
Veitch diagram: A graphic technique used in solving logic circuit design problems.
Venn diagram: A diagram that uses circles and ellipses tore present basic logic relationships.
Verb: A command or instruction that calls for a processing action.
Verifier: A machine for checking data accuracy.
VGA: Abbreviation for Video Graphics Array. A graphics adaptor that provides the highest level of
function and clarity.
Videotext: A telecommunications service blending graphics and text.
Virtual disk: A simulated disk in RAM memory. A virtual disk has characteristics of both RAM memory
and magnetic disk. While residing in memory it adds speed to the processing of data. Items must be
moved to a disk or diskette before powering off the computer or it will be lost.
Virus: Name given to a program that “infects” many computers causing damage to other programs and
Voice acceptance terminal: A terminal capable of generating digital codes from signals spoken by an
Voice input: Spoken commands as direct computer input.
Voice synthesizer: An output device that converts digital signals into audio signals suggestive of human
Volatile: Computer-stored data subject to loops or erasure in the even of power failure.
VRAM: Video RAM.
VSAM: Acronym for virtual storage access (method). A file-management technique.


Wafer: The thin slice of fabricated semiconductor material from which chips are made.
Walkthrough: A step-by-program explanation or review.
Warm boot: The keying sequence that clears all data from memory.
Warnier-Orr-diagram: A structured modeling technique using brief descriptions of data elements to
represent data structures.
Weighted value: The numerical value assigned to a bit as a function of its position in the code word.
White box: Program instructions or code that implements design concepts, and can be reviewed in its
Wildcards: Optional keys on a computer keyboard.
Winchester data module: A sealed, fixed-disk medium that provides high memory capacity and rapid
Winchester drive: A fixed-disk peripheral storage device.
Window: An area of the computer screen in which instructions or other information can appear.
Word: In computer terminology, a group of characters occupying one storage location in a computer.
Word pattern: The smallest meaningful language unit recognized by a machine.
Word processing: The use of a computer program to compose and edit written text.
Word-processing package: Software package that enables the user to enter, store, modify, format, copy
and print text.
Word-wrap: In word-processing, when a word is keyed in that extends beyond the right margin, it’s
automatically moved down to the next line.
Work file: In COBOL, an intermediate file-containing interim outputs that require further sorting.

Workstation: A portable unit combining word-processing, data processing, and data-communications
WORM: Acronym for Write Once Read Many. The concept that allows a user to write a file to a device,
which is then used exclusively for input. No updates are allowed on this type of device. This technology is
found in CD-ROM.
WRITE: An I/O verb in COBOL.
Write lock: A safety mechanism that prevents a user from writing on a disk or diskette possibly damaging
important information.
Write-protected diskette: A diskette whose contents may be viewed but not altered.


Xerography: A no chemical photographic process.
X punch: A punch in the ll position of row or column. Also called ll punch.
X-Y plotter: A device used with a microcomputer to plot coordinate points in graphs form.


Yoke: A group of magnetic recording heads acting as a unit.
Y signal: A signal used in color television broadcasts to transmit information on brightness, etc.


Z: In COBOL, the character used to suppress a zero.
Zero-access store: A fast store from which information is immediately available.
Zero suppression: In computing and data processing, the elimination of superfluous zeros to the left of
the integral part of the quantity.
Zone portion: The first four bits of a byte in EBCDIC.



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