IBM RT PC 10 Hardware Maintenance And Service page 334

hertz (Hz). A unit of frequency equal to one
cycle per second.
Hz. Hertz.
initial program load (lPL). The process of
loading the system programs to prepare the
system to run jobs. See initialize.
initialize. To set counters, switches, addresses,
or contents of storage to 0 or other starting
values at the beginning of, or at prescribed
points in, the operation of a computer routine.
inputloutput
(1/0)
device. A device in a data
processing system by which data may be
entered into the system, received from the
system, or both.
interrupt. (1) To temporarily stop a process.
(2) In data communications, to take an action
at a receiving station that causes the sending
station to end a transminssion.. (3) A signal
sent by an 110 device to the processor when an
error has occurred or when assistance is needed
to complete 1/0. An interrupt usually suspends
execution of the currently executing program.
IPL. initial program load.
1/0. Inputloutput.
k. Prefix kilo; 1000.
K. When referring to storage capacity; 1024.
m. Meter.
M. When referring to computer storage
capacity, 1 048 576.
memory. Storage on electronic chips.
Examples of memory are random access
memory, read only memory, or registers. See
storage.
modem (modulator-demodulator). A device that
converts data from a computer to a signal that
can be transmitted on a communications line,
and converts the signal received to data for the
computer.
operating system. Software that controls the
execution of programs; an operating system
may provide services such as resource
allocation, scheduling, inputloutput control,
and data management.
PEL. Picture element.
picture element (PEL). The smallest
displayable unit on a display.
port. (1) To make the programming changes
necessary to allow a program that runs on one
type of computer to run on another type of
computer. (2) An access point for data input
to or data output from a computer system.
POST. power-on self-test.
power-on self-test (POST). Tests that run first
after initial power on to test the operation of the
system.
power supply. A device that produces the
power needed to operate electronic equipment.
processor. (1) In a computer, a functional unit
that interprets and executes instructions. (2) A
functional unit, a part of another unit such as a
Glossary X-3