IBM DS8000 User Manual page 239

a System z 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.
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
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.
System Storage
See IBM System Storage.
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
40
or 1 099 511 627 776
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
protocols that provide end-to-end
connections between applications over
interconnected networks of different
types.
2) A suite of transport and application
protocols that run over the Internet
Protocol. (GC) See also Internet Protocol
and Transmission Control Protocol.
transparency
See software transparency.
See time sharing option.
TSO
turbo processor
A faster multiprocessor that has six
processors with common access to the
main storage.
U
UFS UNIX filing system.
Ultra-SCSI
An enhanced small computer system
interface.
unconfigure
To delete the configuration.
211
Glossary