ASCII - 1) The acronym for American Standard Code for Information Interchange. 2) A 7- or 8-bit standard for transmission of data for processing.
Backplane - The connector block section of the system where printed circuit boards are inserted.
Baud rate - Synonymous with signal events (usually bits) per second; used as a measure of serial data flow between a computer and/or communication devices.
Bootstrap - A programmed routine consisting of enough instructions to load and transfer control to an input/output device's program. The routine is started by a switch or automatically when the computer is turned on.
Buffer control - A temporary storage memory used to equalize different operating speeds.
Bus error trap - A high-priority interrupt that halts the processor routine and initiates a subroutine.
Byte - A group of binary bits used to represent a single character.
Channel - A path for electrical transmission between two or more points.
Control panel - The part of the system that permits the monitoring and manipulation of an operation through the use of control switches and indicators.
CPU - 1) The acronym for central processing unit. 2) The part of the computer that contains the arithmetic and logical unit, instruction control unit, timing generators, and input/output interfaces of the basic system.
Diagnostic program - A program designed to detect and/or isolate a malfunction in a device, printed circuit board, or component.
DMA - 1) The acronym for direct memory access. 2) A facility that allows input/output transfers to bypass the CPU's general registers and go directly to/from memory.
EIA - The acronym for Electronic Industries Association.
EIA interface - The standard code defined by the Electronic Industries Association for use in data
Error message - A printed statement indicating the system has detected a mistake or malfunction.
Floating-point processing - A method of calculation that automatically moves the decimal point.
FRU - Field-replaceable unit.
Hardcopy - Output in a permanent form (usually on paper or paper tape) rather than in temporary form (such as a visual display on a video terminal).
Head - The part in a disk(ette) drive or magnetic tape drive that reads, records, and erases data on the storage medium being used.
Instruction set - A group of commands that tells the computer what operation to perform.
Input/output (I/O) - A descriptor or devices that accept data for transmission to a computer system (input), and accept data from a computer system for transmission to a user or process (output). Devices such as terminals that perform both functions are known as I/O devices.
LED - The acronym for light-emitting diode.
Line wraparound - Occurs when the end of a line is reached on a video screen; succeeding characters automatically start at the beginning of the next line.
LSI - The acronym for large scale integration.
Memory management - A unit that allows CPU access to memories of 64 K bytes or more, and provides protection and organization of memory areas.
Modem - 1) The acronym for modulator-demodulator. 2) A telecommunications device that provides the appropriate interface between a computer and a communications link.
MOS - The acronym for metal1ic oxide semiconductor.
MSCP - The acronym for mass storage control protocol.
Nonl'olatile memory - A storage medium that retains its data in the absence of power.
ODT - The acronym for on-line debugging technique.
Oersted - A unit of magnetic field strength equal to the magnetic intensity one centimeter from a unit magnetic pole. Abbreviation: Oe.
Off-line - Pertaining to equipment, devices, and events that are not under direct control of a computer.
On-line - Pertaining to equipment, devices, and events that are under direct control of a computer. (Data is introduced into the CPU immediately.)
Parity bit - An extra bit added to a byte or word to ensure that there is always either an even or odd number of bits, according to the logic of the system.
Peripheral del'ice - A device that is external to the CPU and main memory (e.g., a printer, modem, or terminal) but connected to them by appropriate electrical connections.
Processor status word - A register in some computers that indicates the current priority of the CPU, the condition of the previous operation, and other basic control items.
Program counter - A register in the CPU that holds the address of the next instruction (except in the case where the current instruction causes a jump).
PROM - 1) The acronym for programmable read-only memory. 2) A ROM that can be programmed by a user.
Protocol - A formal set of conventions governing the format and relative timing of message exchange between two communicating processes.
Quad module - An option for LSI-II systems that requires four connectors on the backplane.
RAM - 1) The acronym for random-access memory. 2) A memory in which the CPU can access all locations with equal facility.
Random-access - Pertaining to a storage device from which data or blocks of data can be read in any order. (Therefore, in a random-access device, it is not necessary to read from the beginning to retrieve the desired data.)
Real-time - Pertaining to the actual time during which a process takes place.
Reserved instruction trap - A non programmed conditional jump to a specified location that occurs upon the initiation of a reserved instruction.
ROM - 1) The acronym for read-only memory. 2) Preprogrammed memory that can be read from, but not written to.
Scrolling - The upward or downward movement of data on a video screen that allows new data to be displayed.
Subsystem - An organization of computer components (e.g., a tape drive and controller) that makes up a functional part of a larger system.
Trap - A conditional jump to a known memory location, performed automatically by hardware as a side effect of an instruction's execution. The address location from which the jump is made is stored. (A trap is distinguished from an interrupt, which is caused by an external event.)
Utility program - A program used to perform some frequently required process in the operation of a computer.
EK-OLCP5-TM-OO2