Glossary of Terms

Sorry - Trouble with applet, no links here acronym -- Shortening a phrase by taking the first letter of each word.

ALU -- Arithmetic Logic Unit -- A circuit which adds, subtracts, compares, and does other simple but rapid processing on small units of data.

application program -- Program which does something, such as run a payroll or compute the airflow over an airplane wing.

architecture, computer architecture -- The hardware design of a computer; the layout of its internals at the lowest level as seen by a programmer.

ASIC -- Application Specific Integrated Circuit -- Customized electronics on one chip, like buying a tailored suit versus one off the rack.

assembler -- See: symbolic assembler.

assembly language -- Practically the same thing as machine language, but in a form humans find (slightly) easier to read.

BIOS -- Basic Input/Output System - low level programs controlling computer peripherals.

bit -- BInary digiT -- Can be represented by a switch being either ON or OFF; the smallest unit stored in a computer memory.

bit-serial -- Sending data over one wire one bit at a time, rather than in parallel over a "bus" of several wires at once.

bus -- Any number of parallel wires carrying bits lined up like racehorses coming out of a starting gate.

byte -- A "word" of 8 bits. These are enough bits to encode the alphabet: upper/lower case letters, numbers, & punctuation, with room left over.

C -- A programming language (such as BASIC or COBOL) with a very short name.

chip -- A piece of silicon as small or smaller than a fingernail. See: ic.

CISC -- Complex Instruction Set Computer -- The microprocessors in common personal computers have a machine language consisting of hundreds of individual instructions. See: RISC.

CMOS -- Complementary Metal Oxide Semiconductor -- A fabrication process for silicon which yields circuits that use very little power.

code -- Lines from a computer program; "object" code refers to a program which has been translated from some different "source" code.

compiler -- Translates the more English-like statements of a higher level language like C or FORTRAN into machine code the computer can run.

control store -- A memory, either RAM or ROM, which contains microcode.

controller, microcontroller -- A type of microprocessor used to control appliances or monitor and control industrial processes.

CORDIC -- COordinate Rotation DIgital Computer -- A kind of hardware circuit which can do higher math very quickly.

CPU -- Central Processing Unit -- The heart of a computer, that element which runs programs and processes data.

debugger, symbolic debugger -- A software package which helps a programmer fix broken programs.

development system -- A computer system which makes it easy to write software, either for that same system, or for a different computer type.

digital circuitry -- Is based on fast and tiny switches, interconnected to perform counting and computation.

fiber optics -- Connection medium different from wires in which data are sent as pulses of light rather than as pulses of electricity.

GaAs -- gallium arsenide -- A semiconducting compound on which can be made faster circuits than can be fabricated on silicon.

hardware -- Parts of a computer which can be physically seen or touched.

I/O -- Input/Output -- The communication sections of a computing system.

IC -- Integrated Circuit -- a device which contains dozens to millions of transistors and other circuit elements on a single silicon die.

instruction -- Sometimes also called "operation" - A single word of machine code which performs some specific action within a CPU's logic.

ISDN -- Integrated Services Digital Network -- One of dozens of interfaces for sending data, basically all of which are faster than the phone lines.

Java -- A new programming language becoming popular on the Internet. See: OOP

kilo -- K -- Prefix which means multiply by 1,000. E.g., "Kilobits per Second," or "KBS" - standing for a transmission rate over a wire or phone line.

language, programming language -- Software is written in programming languages with names such as BASIC, COBOL, C, and Java. See also: assembly language.

laser diode -- A semiconductor device which transforms an electrical signal into a coherent beam of light.

logic -- Another name for the control and computation circuitry on a chip.

machine language -- Set of all the different instructions a given computer's logic can perform. These are very low level operations; most programmers don't work with machine code. See: assembly language, instruction, microcode.

mega -- M -- Prefix which means multiply by 1,000,000. E.g., "Megabyte," or "MB" - meaning millions of bytes.

memory, computer memory -- Where bits can be stored, typically by the mllions. See: RAM, register, ROM.

microcode -- Some computers have this extra level of programming which is even a step closer to the underlying hardware than machine language.

microprocessor -- A computer on a single chip; The CPU found in personal computers and engineering workstations. See also: controller.

MIMD -- Multiple Instruction Multiple Data -- A type of parallel computer in which each unit can run its own independent program. See also: SIMD.

monitor -- A software package which helps a programmer watch and modify programs as they run. Not to be confused with the "monitor" that it is displayed on.

neural net -- A new and different type of computing circuit made from elements which act more like nerve cells than like simple switches.

OOP -- Object Oriented Programming -- Writing software in reusable modules, as opposed to disorganized "spaghetti code." Java is a new, popular OOP language.

OS -- operating system -- The set of programs which allow a user to tell a computer what to do, such as DOS, Windows, or UNIX.

parallel processing -- Having many (possibly different) CPUs running at the same time to finish programs much faster than a single CPU possibly could.

program, computer program -- A "work order," written in a computer language, which tells a computer how to do something.

PROM -- Programmable Read Only Memory -- Write only once, read many times.

R/R&D -- Research / Research & Development.

RAM -- Random Access Memory -- The most common kind of computer memory; can be read or written in any order.

register -- Hardware which holds a certain number of bits at a time. Registers are a small but very fast part of computer memory.

RISC -- Reduced Instruction Set Computer -- Fewer is often faster when it comes to running machine language instructions. See: CISC.

ROM -- Read Only Memory -- Hard-wired memory which can't be written into.

semiconductor -- Starting material on which computer circuits are fabricated. Neither an electrical conductor nor an insulator.

serial -- See: bit-serial.

silicon -- A semiconducting element upon which most computer circuits today are fabricated.

SIMD -- Single Instruction Multiple Data -- A type of parallel computer in which each unit can only run instructions sent by a master unit. See also: MIMD.

simulator -- A program which runs on one computer but which acts like another, different computer. See: development system.

SOC -- System-On-Chip -- Very very large scale integration (See VLSI), the latest frontier in miniaturization of logic circuits

software -- Computer programs; they run on the hardware.

solid-state -- Electronics based on semiconductors rather than vacuum tubes.

symbolic assembler -- A program which reads an English-like programming language and converts it into machine language. See also: assembly language.

transistor -- The basic electronic solid-state switch.

VLSI -- Very Large Scale Integration -- Pushing the technology so that very tiny transistors can be fabricated so that very large numbers of them (millions) can fit on one integrated circuit die, or "chip."

word, computer word -- A grouping of a certain number of bits; size is usually standardized within a particular architecture. See: byte.