IBM AT 5170 Technical Reference page 473

odd-even check. Synonym for parity check.
offline. Pertaining to the operation of a functional unit without
the continual control of a computer.
one-shot. A circuit that delivers one output pulse of desired
duration for each input (trigger) pulse.
open circuit. (1) A discontinuous circuit; that is, one that is
broken at one or more points and, consequently, cannot conduct
current. Contrast with closed circuit.
(2)
Pertaining to a no-load
condition; for example, the open-circuit voltage of a power
supply.
open collector. A switching transistor without an internal
connection between its collector and the voltage supply. A
connection from the collector to the voltage supply is made
through an external (pull-up) resistor.
operand.
(1)
An entity to which an operation is applied.
(2)
That which is operated upon. An operand is usually identified
by an address part of an instruction.
operating system. Software that controls the execution of
programs; an operating system may provide services such as
resource allocation, scheduling, input/output control, and data
management.
OR. A logic operator having the property that if P is a
statement, Q is a statement, R is a statement, ... , then the OR of P,
Q,
R,...is true if at least one statement is true, false if all
statements are false.
OR gate. A gate in which the output is 1 only if at least one
input is 1.
output. Pertaining to a device, process, or channel involved in an
output process, or to the data or states involved in an output
process.
Glossary-27