A B C D E F G H I J L M N P R S T V W
The unit of a computing system containing the circuits that perform arithmetic and logical operations
pertaining to a characteristic or property involving a selection, choice, or condition in which there are two possibilities, or showing the data in base 2.
an electronic vacuum tube that displays the output of a computer signal
central processing unit (CPU)
the unit of a computer system that include the circuits that control the interpretation and execution of instruction. In many computer systems, the CPU includes the arithmetic logic unit, the control unit, and primary storage unit.
client/server
a computing environment where end user workstations (clients) are connected to micro or mini LAN servers and possibly to mainframe superservers
computer system
computer hardware as a system of input, processing, output, storage, and control components. Thus a computer system consists of input and output devices, primary and secondary storage devices, the central processing unit, the control unit within the CPU, and other peripheral devices
computer terminal
any input/output device connected by telecommunications links to a computer
control unit
a subunit of the central processing unit that controls and directs the operations of the computer system. The control unit retrieves computer instructions in proper sequence, interprets each instruction, and then directs the other parts of the computer system in their implementation
a method of storage where each storage position has a unique address and can be individually accessed in approximately the same period of time without having to search through other storage positions. The same as random access.
direct input/output devices
devices such as terminals that allow data to be input into a computer system or output from the computer system without use of machine-readable media distributed processing
a form of decentralization of information processing made possible by a network of computers dispersed throughout the organization. Processing of user applications is accomplished by several computers interconnected by a telecommunications network, that relying on one large centralized computer facility or on the decentralized operations of several independent computers
downsizing
moving to smaller computing platforms, such as mainframe systems to networks of personal computers and servers
a small figure on a video display that looks like a familiar office order device such as a file folder (for storing a file), a wastebasket (for deleting a file), or a calculator (for switching to a calculator mode.)
a photoelectronic device that allows data to be entered on the face of a video display terminal
liquid crystal displays (LCD’s)
electronic visual displays that form characters by applying an electrical charge to selected silicon crystals
local area network (LAN)
a communications network that typically connects computers, terminal, and other computerized devices within a limited physical area such as an office, building, manufacturing plant, or other worksite.
a flat circular plate with a magnetic surface of which data can be stored by selective magnetization of portions of the curved surface
floppy disk
a small plastic disk coated with iron oxide that resembles a small phonograph record encoded in a protective enveloped. It is a widely used form of magnetic disk media that provide a direct access storage capability for microcomputer systems
hard disk
magnetic tape
a plastic tape with a magnetic surface on which data can be stored by selective magnetization of portions of the surface
mainframe computer
a large-size computer system, typically with a separate central processing unit, as distinguished from microcomputer and minicomputer
microcomputer
a very small computer, range in size from "computer on a chip" to a small typewriter size unit.
Microprocessor
a microcomputer central processing unit (CPU) on a chip. Without input/output or primary storage capabilities in most types
midrange computer
a computer category between microcomputers and mainframes. Examples include minicomputers, network servers, and technical stations.
Minicomputer
a small (e.g. the size of a desk0 electronic, digital, stored-program, general-purpose computer
multimedia presentations
providing information using a variety of media, including text and graphics displays, voice and other audio, photographs, and video segments
multiprocessing
pertaining to the simultaneous execution of two or more instructions by a computer or computer network
an interconnected system of computers, terminals, and communications channels and devices
off-line
pertaining to equipment or devices not under control of the central processing unit
online
pertaining to equipment or devices under control of the central processing unit
optical character recognition (OCR)
the machine identification of printed characters through the use of light sensitive devices
optical disk storage
a secondary storage medium using laser technology to read tiny spots on a plastic disk. The disks are currently capable of storing billions of characters of information
CD-ROM
an optical disk technology for microcomputers featuring compact disks with a storage capacity of over 500 megabytes
optical scanner
a device that optically scans characters or images and generates their digital representations
tablet-style microcomputers that recognize handwriting and hand drawing done by a pen-shaped device on their pressure-sensitive display screens
peripheral devices
in a computer system, any unit of equipment, distinct from the central processing unit, that provides the system with input, output, or storage capabilities
plasma displays
output device that generate a visual display with electrically charged particles of gas trapped between glass plates
plotters
a hard-copy output device that produces drawings and graphical displays on paper or other materials
pointing devices
devices that allow end users to issue commands to make choices by moving a cursor on the display screen
mouse
a small device that is electronically connected to a computer and is moved by hand on a flat surface in order to move the cursor on a video screen in the same direction. Buttons on the mouse allow users to issue commands and make responses and selection.
pointing stick
a small buttonlike device on a keyboard which moves the cursor on the screen in the direction of the pressure placed upon it
tracer ball
a rollerball device set in a case used to move the cursor on a computer’s display screen
primary storage unit printers processing speeds secondary storage device
storage that supplements the primary storage of a computer. Synonymous with auxiliary storage
microelectronics storage circuitry etched on tiny chips of silicon or other semiconducting material. The primary storage of most modern computers consists of microelectronics semiconductor storage chips for random access memory (RRAM) and read only memory (ROM).
RAM: Random Access Memory. One of the basic types of semiconductor memory used for temporary storage of data or programs during processing. Each memory position can be directly sensed (read) or changed (write) in the same length of time, irrespective of its location on the storage medium.
ROM: Read Only Memory. A basic type of semiconductor memory used for permanent storage. Can only be read, not "written", that is, changed. Variations are Programmable Read Only Memory (PROM) and Erasable Programmable Read Only Memory (EPROM).
sequential access
A sequential method of storing and retrieving data from a file.
storage capacity elements
bit: a contraction of "binary digit." It can have the value of 0 or 1.
Byte: a sequence of adjacent binary digits operated on as a unit and usually shorter than a computer word. In many computer systems, a byte is a grouping of eight bits that can represent one alphabetic or special character or can be "packed’ with two decimal digits
kilobyte: megabyte: one million bytes. More accurately, 2 to the 20th power, or 1,048,576 in decimal notation
gigabyte: one billion bytes or 2 to the 30th power
terabyte: on trillion bytes, or 2 to the 40th power, or 1,0009,5111,627,776 bytes in decimal form
supercomputer
a special category of large computer systems tat are the most powerful available. They are designed to solve massive computational problems.
millisecond: a thousandth of a second
microsecond: a millionth of a second
nanosecond: one billionth of a second
picosecond: one trillionth of a second
touch-sensitive screen:
an input device that accepts data input by the placement of a finger on or close to the CRT screen
voice recognition
direct conversation of spoken data into electronic form sizable for entry into a computer system. Also called voice data entry
voice response
volatile memory
memory (such as electronic semiconductor memory) that loses its contents when electrical power is interrupted
This page was created by David Lewis on 6/18/97