| A |
- Ampere; a charge of one coulomb passing a point in one second. 2. Abbreviation for Angstrom; one 10-billionth of a meter. (The Angstrom abbreviation is actually the Norwegian capital A for the Norwegian letter aa. It has a diacritical mark, a circle, attached to the tip of the A. We could not create it here.)
See also ampere and angstrom entries.
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| A Programming Language |
(APL). A high-level mathematical programming language developed by Kenneth Iverson in the 1960s. It can be run on many different kinds of computers, and is still used for some applications. APL uses its own special characters to represent operations.
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| A-B box |
A box that enables two or more computers to take turns using a peripheral device such as a printer or scanner. The user turns a switch on the box choosing A, B, etc. to change from one computer to another.
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| A/D converter |
Analog-to-digital converter. A device that converts data from analog to digital form. For example, an audio CD is made by converting analog sound signals into digital data.
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| A/UX |
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| A: |
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| AA |
Auto Answer. Some modems can be set up to accept telephone calls and automatically establish a connection; this ability is called auto answer. When the AA light on the modem goes on, the modem is set to auto answer.
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| AAT |
Average Access Time. The average amount of time it takes for a storage peripheral to transfer data to the CPU.
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| abend |
ABnormal END. From an error message on the IBM 360. Also called a crash or bomb, it is the result of erroneous software logic or hardware failure.
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| ABI |
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| ABIOS |
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| ABIST |
Automatic Built-In Self-Test. An automatic self-test performed by an IBM computer to make sure its various components are functioning properly.
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| abort |
To cancel a command or stop a transmission.
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| Abort, Retry, Ignore, Fail? |
A DOS error message that is displayed when the computer has trouble reading a disk or file.
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| ABR |
(Automatic Baud Rate detection). The process in which a receiving device examines the first character of an incoming message to determines its speed, code level, and stop bits. Having this automatic function makes it possible to receive data from different transmitting devices operating at different speeds without having to establish data rates in advance.
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| abscissa |
The x coordinate on an x,y graph (y is the ordinate).
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| absolute address |
A specific location in the memory of a computer or peripheral device, which is not defined by reference to any other address. It is sometimes derived by taking a base address and adding to it a relative address.
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| absolute cell reference |
In a spreadsheet, a reference to one specific cell, rather than a relative reference which would indicate the placement of a cell in reference to the current cell (for example, four rows above in the same column). Since cell references in a spreadsheet are relative references by default, an absolute cell reference must be indicated; this is done by different codes in different programs, but often by adding a dollar sign: $A42, $B$12.
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| absolute path |
A designation of the location of a file which is given in relation to the root directory; it includes the root directory and the descending series of subdirectories leading to the end file.
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| absolute pathname |
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| absolute reference |
In a spreadsheet, a reference to one specific cell, rather than a relative reference which would indicate the placement of a cell in reference to the current cell (for example, four rows above in the same column). Since cell references in a spreadsheet are relative references by default, an absolute reference must be indicated; this is done by different codes in different programs, but often by adding a dollar sign: $A42, $B$12.
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| absolute vector |
A vector whose end points are indicated as absolute coordinates.
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| Abstract Syntax Notation One |
(ASN.1). The ISO language for describing abstract syntax.
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| Abstract Windows Toolkit |
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| AC |
Alternating Current. Alternating current differs from direct current (DC) in that its direction is reversed 60 times per second (50 times per second in some countries). The electricity in ordinary home or office outlets is AC.
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