IBM 6151 Maintenance And Service Manual page 750

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
terminal or a processing unit, that
interprets and executes instructions.
program. A file containing a set of
instructions conforming to a particular
programming language syntax.
radio frequency (RF). An ac frequency
that is higher than the highest audio
frequency. So called because of the
application to radio communication.
RAM. See random access memory and
read/write memory.
random access memory (RAM).
Read/write memory.
raster. A predetermined pattern of lines
that provides uniform coverage of a
display space.
read. To acquire or interpret data from a
storage device, from a data medium, or
from another source.
read-only memory (ROM). A storage
device whose contents cannot be modified.
X-4 Service Manual
The memory is retained when power is
removed.
read/write memory. A storage device
whose contents can be modified. Also
called RAM.
resident. Permanently located in
memory, such as read-only memory.
ROM. See read-only memory.
RS232C. A standard by the EIA for
communication between computers and
external equipment.
setup. (1) In a computer that consists of
an assembly of individual computing
units, the arrangement of interconnections
between the units, and the adjustments
needed for the computer to operate.
(2) The preparation of a computing system
to perform a job or job step. Setup is
usually performed by an operator and
often involves performing routine
functions, such as mounting tape reels.
(3) The preparation of the system for
normal operation.
software. (1) Computer programs,
procedures, and rules concerned with the
operation of a data processing system.
(2) Contrast with hardware.
source number. The two leftmost digits
of a service request number. Identifies the
entity that sensed the error.
SRA number. Service repair action
number.
SRN. Service request number.