Glossary “A”

The purpose of this glossary is to present definitions for some of the terms that are often used in the field of computers and data processing. Abacus The earliest device that qualifies as a digital computer. It permits the user to represent numbers by the position of beads as a rack. Positioning the beads appropriately can carry out simple addition and subtraction rapidly and efficiently. Access time The time interval between the instant at which data is called for from a storage device and the instant delivery begins. Accumulator A local storage area, called a register, in which the result of an arithmetic or logic operation is formed. Acoustic coupler A special type of modern (communications device), which allows an ordinary telephone to be used with a computer device for data transmission. Ada A high level programming language named after Ada Augusta, a friend of Charles Babbage. It is a general purpose programming language developed at the request of the U.S Department of Defense for use in military applications. Adder A logic circuit capable of forming the sum of two or more quantities. Address An identification, represented in the form of a name, label, or number, for designating a particular location in storage area. Address register A local storage register, which contains the address of the next instruction to be executed ALGOL (ALGOrithmic Language) An algebraic, high-level language similar to FORTRAN that is widely used in Europe. Algorithm A sequence of precise and unambiguous instructions for solving a problem in a finite number of operations. Alphanumeric Pertaining to a character set that contains letters, digits and usually other special characters such as the comma, dollar sign, plus sign etc. ALU (Arithmetic Logic Unit) The unit of a computing system, which performs all mathematical and logical operations. It is one of the components of the central processing unit (CPU) of the computer. Analog computer A computer that operates on data, which is in the form of continuously variable physical quantities such as electrical current. ANSI (American National Standards Institute) A U.S based national organization that establishes uniform standards in several fields. APL (A Programming Language) A very powerful high-level language that is well suited for specifying complex algorithms. It is a real-time language usually used in an interpretive and interactive manner and was developed primarily for scientific applications. Application program Software designed for a specific purpose such as pay calculation, processing of examination results, stores accounting and inventory control etc. Architecture The organization and interconnection of the various components of a computer system. Artificial Intelligence A branch of computer science that deals with computers that possess reasoning, learning and thinking capabilities that resemble those of humans. ASCII (American Standard Code for Information interchange) A standard coding system for computers. ASCII-7 is a 7-bit code and its extended version ASCII-8 is an 8-bit code. Assembler A computer program, which translates an assembly language program to its machine language equivalent. Assembly language A low-level programming language in which mnemonics are used to code operations and alphanumeric symbols are used to code operations and alphanumeric symbols are used for addresses. This language lies between high-level language (FORTRAN, COBOL etc.) and machine language (the 1s and 0s the computer understands). Asynchronous communication Communication between units operating independently. Audio response An output medium that produces verbal responses from the computer system. Auxiliary storage A storage that supplements the primary internal storage of a computer. Often referred to as secondary storage, this section of the computer’s memory is characterized by low cost per bit stored, but it generally has an operating speed far slower than that of the primary storage.