HARDWARE.— The physical apparatus of a
computer system consisting of the equipment itself.
HEAD CRASH.— A catastrophic malfunction in a
hard-disk drive that occurs when the read/write head
touches the spinning disk, gouging its magnetic surface
and destroying both the data and the head.
IMPACT PRINTER.— A printer that works by
striking a raised character or a pin against paper through
an inked ribbon.
INK-JET PRINTER.— A nonimpact printer that
works by spraying electrically charged droplets of ink
onto paper.
INPUT.— Simply stated, input is any type of data
or facts fed into a computer.
INPUT/OUTPUT (I/O) PORT.— An outlet on a
computer circuit board for attaching input or output
devices such as keyboards or printers.
INSTRUCTIONS.— An elementary machine-
language order to the central processing unit (CPU) of
a computer. A sequence of such instructions forms a
program.
INTEGRATED CIRCUIT.— An electronic
circuit whose components are formed on a single piece
of semiconductor material. (A semiconductor material
is a substance such as silicon whose conductivity falls
between that of a metal and an insulator.)
INTERFACE.— An electronic circuitry that allows
two devices to communicate with each other.
INTERRUPT.— A temporary halt in executing a
program, or the signal that causes that halt.
JOYSTICK.— A handheld lever that can be tilted
in various directions to control the movement of a cursor
on a display screen.
KEYBOARD.— An arrangement of keys, like
those on a typewriter, used to enter data into a computer.
KILOBYTE (K BYTE).— A unit of measure equal
to 1,024 bytes often used as a measure of memory
capacity. (One K is equal to 1,024 or 2 to the 10th
power.)
LANGUAGE.— A set of rules or conventions to
describe a process to a computer.
LASER PRINTER.— A form of electrostatic
printer that employs a laser to electrically charge a piece
of paper in a desired pattern to which particles of dry ink
then cling.
LIGHT PEN.— A pen-shaped photosensitive input
device used to direct the computer or to draw images by
touching a cathode-ray tube (CRT) display.
MAGNETIC TAPE.— Plastic tape coated with a
magnetic material on which you store information in the
form of magnetized spots.
MEMORY.— The storage facilities of a computer.
This term is applied only to internal storage as opposed
to external storage such as disks or tapes.
MENU.— A list of commands, functions, or graphic
symbols shown on a display screen or a digitizing tablet.
MICROCOMPUTER.— A desktop or portable
computer, based on a microprocessor and meant for a
single usen often called a home or personal computer.
MICROPROCESSOR.— A single chip containing
all the elements of a computer’s CPU.
MODEM.— A device that enables data to be
transmitted between computers, generally over
telephone lines but sometimes on
fiber-optic cable or radio frequencies.
MONITOR.— A television-like device for
displaying data. (It is referred to very simply as the
computer screen).
MOUSE.— A handheld input device that, when
rolled across a flat surface, causes a cursor to move in a
corresponding way on a display screen.
MULTIPROGRAMMING.— The ability in a
computer to switch rapidly among several programs in
memory to give the appearance that all are being run
simultaneously.
NETWORK DATA BASE.— A system of data
organization in which any discrete group of facts (or a
record) can be linked to any other.
ON-LINE.— The characteristic of being
immediately accessible by a computer’s CPU. This
term also refers to the technique of entering data and
instructions directly into a computer.
OPERATING SYSTEM.— A complex program
used to control, assist, or supervise all other programs
that run on a computer system. The operating system is
also referred to as DOS (disk operating system) by most
microcomputer users.
OPTICAL CHARACTER READER (OCR).—
A unit capable of recognizing characters in a
typeface, such as the typeface on a bank check.
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