Selected Computer Terms for True BASIC Book



algorithm: formal method for solving a problem using a

sequence of logical steps


application program: computer program that performs some

specific task; see editor


argument: value, variable, or expression attached to a procedure

name when the procedure is called


arithmetic operator: addition (+), subtraction (-), multiplication

(*), division (/), or exponentiation (^)


array: indexed variable that can store sets of numeric or string



ASCII: coding scheme used to represent characters in a digital



assignment statement: LET keyword


assignment operator: the equal sign (=)


binary file: file of binary instructions


binary instruction: sequence of binary numbers that tells the

computer to do something


bit: binary digit, has value of 0 or 1


branch structure: program structure that chooses one of two or

more choices


bug: program error


built-in function: function that is part of the True BASIC



Bye command: exit the True BASIC system


byte: unit of eight bits


call: using a function name in an expression or using the CALL



channel number: True BASIC identifying number for a file or



Clear command: erase the current program, from File menu


click: press left mouse button when mouse cursor is on selected



command window: lower True BASIC window where

commands are entered


compiler: translates a source program into an object program


compound logical expression: two or more simple logical

expressions joined by one or more conjunctions


concatenation: join two strings together, operator is the

ampersand (&)


control variable: variable whose value determines when a loop



CPU: central processing unit (an electronic chip) of a computer


current program: program presently running or in the editing



debugging: process of finding and removing program errors


decimal digit: digit appearing in a number after the decimal point


directory: named space on disk where files can be stored, DOS



disk: rotating magnetic platter where files are stored


display unit: televisionlike screen that displays text and graphics


double-click: click mouse twice in rapid succession


drag down: put cursor on menu title, hold mouse button down,

and pull down the menu


editing window: upper window where programs are edited


editor: computer program for creating and modifying files


element: single storage location in an array


EOF marker: character marking the end of a file


EOLN marker: set of two characters marking the end of a text

file line


equality operator: the equal sign (=)


error handler block: block of statements where each trapped

error is handled as directed by the program


external procedure: procedure placed after the program END



file folder: named space on disk where files can be stored, a

MacOS term


file name: name associated with a specific file


file pointer: imaginary marker that marks some location in a file


file: named sequence of text characters or binary numbers,

usually stored on disk


final value: last value of a loop control variable


Find command: find a sequence of characters, from Edit menu

or command line


fixed disk: disk, usually non-removable, with high storage



floppy diskette: removable disk with low storage capacity


FUNCTION.TRU file: help file containing a list of all built-in



function: block of computer statements that performs some

calculation and return a value


gigabyte: 1024 megabytes or about one billion bytes


global variable: variable that is used and known throughout a



GUI: graphical user interface that displays graphics on the

monitor screen


hard disk: see fixed disk


hardware: mechanical and electrical components of a computer



icon: little picture on a GUI that represents a program


indexed variable: see array


initial value: first value of a loop control variable


internal procedure: procedure placed before the program END



keyboard: typerwriterlike device for entering characters into the



kilobyte: 1024 bytes


line number: unique number identifying a program statement


local variable: variable that is first used and known within a

single procedure


logical expression: expression that has a value of only true or



logical function: function that returns a value of only true or false


loop structure: program structure that repeats a block of

statements several times


looping: process of executing a loop


machine language instruction: see binary instruction


MacOS: operating system for Apple Macintosh computers


megabyte: 1024 kilobytes or about one million bytes


memory address: location of a specific memory byte, expressed

in numbers


memory: electronic chips that store information in a computer


monitor: see display unit


mouse cursor: block or arrow cursor that moves when mouse is



MS-DOS: Microsoft disk operating system for IBM PC-

compatible computers


multi-dimensional array: array with more than one index


nested loops: one loop enclosed entirely within another loop


New command: create a new program, from File menu


null string: an empty string, contains no characters


number: numeric value, a real number


numeric expression: formula or function that yields a numeric



numeric function: function that returns a numeric value


numeric variable: named memory location where a number can

be stored


object program: program of binary instructions


Old command: open an existing program, from command line


one-dimensional array: array with only one index


Open command: open an existing program, from File menu


operating system: software that supervises computer operations

and manages file directories or folders


output window: window where program results are displayed,

Version 5 or MacOS


parameter: variable attached to a procedure heading statement


pass: making values available to a procedure through arguments

and parameters


path name: file name plus directory name(s) specifying the

location of a file


PC-DOS: IBM disk operating system for IBM PC computers


printer: device to print computer output on paper


procedure: general term for a function or subroutine


program output: results produced when a program is executed or




program statement: language statement that when compiled, tells

computer to do something


programmed function: function written by a computer



protected block: block of statements where all errors are trapped


Quit command: exit the True BASIC system


RAM: random access memory, see memory


random number generator: mathematical expression that creates

random numbers


remark statement: non-executable program statement that makes

a comment



returns: makes the value stored in a function name available to

the calling unit


root directory: primary disk directory from which all others



Run command: execute the current program, from Run menu or

command line


Save As command: save the current program with a new name,

from File menu


Save command: save the current program, from File menu or

command line


seed value: initial value used to start a random number generator


sentinel: variable that indicates whether some action has or has

not taken place


single-step: execute a program statement by statement by

pressing a key for each step


software: operating system and application programs of a

computer system


source program: program of language (True BASIC) statements


source window: window where the source program is

displayed, Version 5


STATMENT.TRU file: help file containing a list of all program



string expression: formula or function that yields a string value


string function: function that returns a string value


string variable: named memory location where a string can be



string: string value, a sequence of one or more ASCII characters


subroutine: block of computer statements that performs some



substring: designated part of a string


TERMS.TRU file: help file for computer terms and their



text cursor: underline or I-beam cursor showing insertion point

of the next character


text file: file of ASCII text characters


trapping: process of finding a program error and allowing the

program to handle it


True BASIC: advanced BASIC language, complies with the

ANSI BASIC standard


two-dimensional array: array with two indices


user-friendly: property of a program that makes it easy to use


variable value: numeric, string, or array value stored in a named

memory location


variable: named memory location where information can be



Windows: Microsoft GUI usually combined with MS-DOS