microcode. Acode, representing the instructions
of an instruction set, that is implemented in a
part of storage that is not program-addressable.
microprocessor. Anintegrated circuit that
accepts coded instructions for execution; the
instructions may be entered, integrated, or stored
internally.
microprogram. (1) Asequence of elementary
instructions that correspond to a specific
computer operation, that is maintained in special
storage, and whose execution is initiated by the
introduction of a computer instruction into the
instruction register of a computer.(2) A group of
micro instructions that when executed perform a
preplanned function.
migration. See conversion.
MIM. Media Information Message
MSB. Most significant bit.
O
OEM. Original equipment manufacturer.
P
physical end of tape. Apoint on the tape
beyond which the tape is not permitted to move.
primed. Pertaining to a condition of a tape
drive when the controlling computer addresses
the drive but the drive is not in a ready state.
processing application. The execution of a
systematic sequence of operations performed on
data to accomplish a specific purpose.
Q
quiesce. Tobring a device or system to a halt
by a rejection of new requests for work.
R
read-type commands. Any commands that
cause data to be read from tape.
record. Acollection of related data or words,
treated as a unit; for example, in stock control,
each invoice could constitute one record.
recording density. Thenumber of bits in a
single linear track measured per unit of length of
the recording medium.
retension. The process or function of tightening
the tape onto the cartridge, if it is sensed that the
tape has a loose wrap on the cartridge.
S
SAN. Storage Area Network
SARS. Statistical Analysis and Reporting
System
SCSI. Small computer system interface.
SCSI address. The hexadecimal representation
of the unique address (0–F) assigned to a SCSI
device. This address would normally be assigned
and set in the SCSI device during system
installation.
SCSI device. Ahost adapter or a target
controller that can be attached to the SCSI bus.
SCSI ID. The bit-significant representation of
the SCSI address referring to one of the signal
lines DB (F–0).
short wave. AFibre Channel cable that has an
850 nm wave length.
SIM. Service Information Message
special feature. Aspecific design addition to an
IBM product that is quoted in the IBM Sales
Manual and ordered separately.
standard function. The significant design
elements of an IBM product that are included as
part of the basic standard product.
synchronization. The process of coordinating
the activities of the controlling computer and the
magnetic tape subsystem to obtain the condition
in which the buffer is empty and the tape is in
the correct position for the next operation.
Glossary 137