IBM 5150 Technical Reference page 285

NOT. A logical operator having the property that if P is a
statement, then the NOT of P is true if P is false, false if P is true.
NRZI. Non-return-to-zero change-on-ones recording.
ns. Nanosecond; 0.000 000 001 second.
NUL. The null character.
null character (NUL). A control character that is used to
accomplish media-fill or time-fill, and that may be inserted into or
removed from, a sequence of characters without affecting the
meaning of the sequence; however, the control of the equipment
or the format may be affected by this character.
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 coUector. 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.
Glossary-24