System/390
See S/390.
system adapter identification number (SAID)
The unique identification number that is
automatically assigned to each DS8000
host adapter for use by Copy Services.
System Management Interface Tool (SMIT)
An interface tool of the AIX operating
system for installing, maintaining,
configuring, and diagnosing tasks.
System Modification Program
A program used to install software and

software changes on MVS systems.

T

TAP See Telocator Alphanumeric Protocol.

target A SCSI device that acts as a subordinate

to an initiator and consists of a set of one
or more logical units, each with an
assigned logical unit number (LUN). The
logical units on the target are typically I/O
devices. A SCSI target is analogous to a
zSeries control unit. See also small

computer system interface.

target device
One of the devices in a dual-copy or
remote-copy volume pair that contains a
duplicate of the data that is on the source
device. Unlike the source device, the
target device might only accept a limited
subset of data. See also source device.

TB See terabyte.

TCP/IP
See Transmission Control

Protocol/Internet Protocol.

Telocator Alphanumeric Protocol (TAP)
An industry standard protocol for the input
of paging requests.
terabyte (TB)
1) Nominally, 1 000 000 000 000 bytes,
which is accurate when speaking of
bandwidth and disk storage capacity.
2) For DS8000 cache memory, processor
storage, real and virtual storage, a

terabyte refers to 2

40
or 1 099 511 627
776 bytes.
terminal emulator
A function of the management console
that allows it to emulate a terminal.
thousands of power-on hours (KPOH)
A unit of time used to measure the mean
time between failures (MTBF).
time sharing option (TSO)
An operating system option that provides
interactive time sharing from remote
terminals.
TotalStorage
See IBM TotalStorage.

TPF See transaction processing facility.

track A unit of storage on a CKD device that

can be formatted to contain a number of
data records. See also home address,

track-descriptor record, and data record.

track-descriptor record (R0)
A special record on a track that follows the
home address. The control program uses
it to maintain certain information about the
track. The record has a count field with a
key length of zero, a data length of 8, and
a record number of 0. This record is
sometimes referred to as R0.
transaction processing facility (TPF)
A high-availability, high-performance IBM
operating system, designed to support
real-time, transaction-driven applications.
The specialized architecture of TPF is
intended to optimize system efficiency,
reliability, and responsiveness for data
communication and database processing.
TPF provides real-time inquiry and
updates to a large, centralized database,
where message length is relatively short in
both directions, and response time is
generally less than three seconds.
Formerly known as the Airline Control
Program/Transaction Processing Facility
(ACP/TPF).
Transmission Control Protocol (TCP)
A communications protocol used in the
Internet and in any network that follows
the Internet Engineering Task Force
(IETF) standards for internetwork protocol.
TCP provides a reliable host-to-host
protocol between hosts in packet-switched
communications networks and in
interconnected systems of such networks.
It uses the Internet Protocol (IP) as the
underlying protocol.
Transmission Control Protocol/Internet
Protocol (TCP/IP)
1) A combination of data-transmission
350 IBM TotalStorage DS8000: Messages Reference