IBM E10, Руководство по обслуживанию, Страница: 267 / 279

service processor. A dedicated processing unit which
is used to service a storage facility.
shared storage. Storage within storage facility that is
configured such that multiple similar or different hosts
can concurrently access the storage. The storage unit
has a uniform appearance to all hosts.
SIM. Service-Information Message.
SIMM. Single In-line Memory Module.
SMIT. System Management Interface Tool.
SNMP. Simple Network Management Protocol.
software transparency. Criteria applied to a
processing environment that states that changes do not
require modifications to the host software in order to
continue to provide an existing function.
spare. A disk drive that is used to receive data from a
device that has experienced a failure that requires
disruptive service. A spare can be pre-designated to
allow automatic dynamic sparing. Any data on a disk
drive that you use as a spare is destroyed by the
dynamic sparing copy process.
SRN. Service Request Number or System Reference
Number.
SSA. Serial Storage Architecture. An IBM standard for
a computer peripheral interface. The interface utilizes a
SCSI logical protocol over a serial interface that
configures attached targets and initiators in a ring
topology.
SSG. Sequential Stage Group
SSID. SubSystem IDentifier.
stacked status. An ESA/390 term for status that the
control unit is holding for the channel because the
channel responded with the stack-status control the last
time the control unit attempted to present the status.
stage. The process of reading data into cache from a
disk drive module.
Self-Timed Interface (STI). An interface that has of
one or more conductors that transmit information serially
between two interconnected units without requiring any
clock signals to recover the data. The interface performs
clock recovery independently on each serial data
stream, and uses information in the data stream to
determine character boundaries and inter-conductor
synchronization.
STI. Self-Timed Interface.
storage complex. Multiple storage facilities.
storage controller. A physical unit which provides an
interface between one or more storage devices and a
host computer by providing the function of one or more
logical subsystems. The storage controller may provide
functions that are not provided by the storage device.
The storage controller is composed of one or more
clusters.
storage device. A physical unit which provides a
mechanism to store data on a given medium such that it
can be subsequently retrieved. Also see disk drive
module.
storage facility. (1) A physical unit which consists of a
storage controller integrated with one or more storage
devices to provide storage capability to a host computer.
(2) A storage server and its attached storage devices.
storage server. A that manages attached storage
devices and provides access to the storage or storage
related functions for one or more attached hosts.
stripe. The set of tracks in a RAID Rank that have the
same parity track. Full stripe writes reduce the RAID 5
write penalty.
striping. A technique that distributes data in bit, byte,
multibyte, record, or block increments across multiple
disk drives.
subchannel. A logical facilities of a channel
subsystem associated with the management of a single
device.
subsystem identifier (SSID). A number that uniquely
identifies a logical subsystem within a computer
installation.
synchronous write. A write operation whose
completion is indicated after the data has been stored
on a storage device.
T
target. The SCSI term for a storage controller.
TCP. Transmission Control Protocol
track. A unit of storage on a CKD device consisting
that can be formatted to contain a number of data
records. Also see home address, track-descriptor
record, and data record.
track-descriptor record. A special record on a track
following the home address that is used by the control
program 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.
transparency. See software transparency.
TTY. TeleTYpewriter.
Glossary of Terms and Abbreviations
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