Specifications

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/Internet Protocol
(TCP/IP). (1) Together, the Transmission Control
Protocol and the Internet Protocol provide end-to-end
connections between applications over interconnected
networks of different types. (2) The suite of transport
and application protocols that run over the Internet
Protocol. See Internet Protocol.
transparency. See software transparency.
TSO. See time sharing option.
U
UFS. UNIX filing system.
ultra-SCSI. An enhanced Small Computer System
Interface.
unit address. The ESA/390 term for the address
associated with a device on a given control unit. On
ESCON or FICON interfaces, the unit address is the
same as the device address. On OEMI interfaces, the
unit address specifies a control unit and device pair on
the interface.
unprotected volume. An AS/400 term that indicates
that the AS/400 host recognizes the volume as an
unprotected device, even though the storage resides on
a RAID array and is therefore fault tolerant by definition.
The data in an unprotected volume can be mirrored.
Also referred to as an unprotected device.
upper-layer protocol. The layer of the Internet
Protocol (IP) that supports one or more logical protocols
(for example, a SCSI-command protocol and an
ESA/390 command protocol). Refer to ANSI
X3.230-199x.
UTC. See Coordinated Universal Time.
utility device. The ESA/390 term for the device used
with the Extended Remote Copy facility to access
information that describes the modifications performed
on the primary copy.
V
virtual machine (VM). A virtual data processing
machine that appears to be for the exclusive use of a
particular user, but whose functions are accomplished
by sharing the resources of a real data processing
system.
vital product data (VPD). Information that uniquely
defines the system, hardware, software, and microcode
elements of a processing system.
VM. See virtual machine.
volume. In Enterprise Systems Architecture/390, the
information recorded on a single unit of recording
medium. Indirectly, it can refer to the unit of recording
medium itself. On a nonremovable-medium storage
device, the term can also indirectly refer to the storage
device associated with the volume. When multiple
volumes are stored on a single storage medium
transparently to the program, the volumes can be
referred to as logical volumes.
VPD. See vital product data.
W
Web Copy Services. See IBM TotalStorage Enterprise
Storage Server Copy Services.
worldwide node name (WWNN). A unique 64-bit
identifier for a host containing a fibre-channel port. See
worldwide port name.
worldwide port name (WWPN). A unique 64-bit
identifier associated with a fibre-channel adapter port. It
is assigned in an implementation- and
protocol-independent manner.
write hit. A write operation in which the requested
data is in the cache.
write penalty. The performance impact of a classical
RAID 5 write operation.
WWPN. See worldwide port name.
X
XRC. See Extended Remote Copy.
xSeries. An IBM Eserver product that emphasizes
architecture.
Z
zSeries. An IBM Eserver product that emphasizes
near-zero downtime.
zSeries storage. See S/390 and zSeries storage.
Glossary 201
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|