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This glossary defines important terms and
abbreviations used in this service guide. If you
cannot find the term you are looking for, see the
Index or the IBM Dictionary of Computing
This glossary includes terms and definitions from:
v
The American National Dictionary for
Information Systems, ANSI X3.172-1990,
copyright 1990 by the American National
Standards Institute (ANSI). Copies may be
purchased from the American National
Standards Institute, 11 West 42 Street, New
York, New York 10036. Definitions are identified
by the symbol (A) after the definition.
v
The ANSI/EIA Standard—440-A: Fiber Optic
Terminology. Copies may be purchased from
the Electronic Industries Association, 2001
Pennsylvania Avenue, N.W., Washington DC
20006. Definitions are identified by the symbol
(E) after the definition.
v
The Information Technology Vocabulary,
developed by Subcommittee 1, Joint Technical
Committee 1, of the International Organization
for Standardization and the International
Electrotechnical Commission (ISO/IEC
JTC1/SC1). Definitions of published parts of this
vocabulary are identified by the symbol (I) after
the definition; definitions taken from draft
international standards, committee drafts, and
working papers being developed by ISO/IEC
JTC1/SC1 are identified by the symbol (T) after
the definition, indicating that final agreement
has not yet been reached among the
participating National Bodies of SC1.
A
access. (1) To obtain the use of a computer resource.
(2) In computer security, a specific type of interaction
between a subject and an object that results in flow of
information from one to the other.
alert. A message or log that a storage facility
generates as the result of error event collection and
analysis. An alert indicates that you need to perform
some service action.
allegiance. The ESA/390 term for a relationship that is
created between a device and one or more channel
paths during the processing of certain conditions. Refer
to implicit allegiance, contingent allegiance, and
reserved allegiance.
ANSI. American National Standards Institute. A
standards committee body for the United States.
array. An arrangement of related disk drive modules
that you have assigned to a group.
ASCII. American national Standard Code for
Information Interchange. A coding scheme defined by
ANSI X3.4-1977 which is used to represent various
alphabetic, numeric, and special symbols with a
seven-bit code.
availability. The degree to which a system or resource
is capable of performing its normal function.
B
BIST. Built-In Self-Test.
bit. binary digit. The storage medium required to store
a single binary digit.
block. A group of consecutive bytes.
boot. To load an operating system or start the system.
BOS. Base Operating System.
byte. An aggregation of eight bits. The storage
medium required to store eight bits.
C
cache (memory). Typically refers to volatile memory
used to improve access times on data or instructions
accesses. The cache memory is typically smaller and
faster than the primary memory or storage medium. On
a storage facility, the cache memory is used to improve
the performance of accesses to data that ultimately
resides on the storage devices in the storage facility.
cache fast write. A form of fast write where the
subsystem writes the data directly to cache, where it is
available for later destaging.
CCR. Channel Command Retry.
CCW. Channel Command Word. The ESA/390 term for
a data structure that is used to specify an I/O operation
to the channel subsystem.
CD-ROM. Compact Disc Read-Only Memory.
CEC. Computer Electronic Complex. The set of
hardware facilities associated with a host computer.
channel. The ESA/390 term for the part of a channel
subsystem that manages a single I/O interface between
a channel subsystem and a set of control units.
Channel-Command Retry (CCR). An ESA/390 term
for a protocol used between a channel and a control
unit which allows the control unit to request that the
current command be reissued.
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VOLUME 3, ESS Service Guide