95741 Sixth Edition Glossary-1
Glossary
This glossary defines abbreviations and new
or special terms used in this publication.
Some of the definitions are taken from the
IBM Dictionary of Computing. The letters in
parentheses that follow some definitions
indicate the source of the definition:
(A) The American National Standard
Dictionary for Information Systems, ANSI
X3.172-1990, copyright 1990 by the American
National Standards Institute (ANSI).
(E) The ANSI/Electronic Industries
Association (EIA) Standard-440-A, Fiber Optic
Terminology.
(I) The Information Technology Vocabulary,
developed by Subcommittee 1, Joint
Technical Committee 1, of the International
Organization for Standardization and
International Electrotechnical Commission
(ISO/IEC/JTC1/SC1).
(IBM) The IBM Dictionary of Computing,
copyright 1994 by IBM.
(T) Draft international standards committee
drafts, and working papers being developed
by the ISO/IEC/JTC1/SC1.
A
access time The time interval between the
instant at which a call for data is initialized
and the instant at which the delivery of data
is completed. (T)
adapter Hardware used to join different
optical fiber connector types. (IBM)
address A character or group of characters
that identifies a register, a particular part of
storage, or some other data source or
destination. (A)
AL_PA See Arbitrated Loop Physical Address.
alphanumeric Pertaining to data that
consist of letters, digits, and usually other
characters, such as punctuation marks. (T)
(A)
Arbitrated Loop A topology in Fibre
Channel that provides multiple connections
for devices that share a single loop, over
which only two devices can communicate at
once. Similar to the SCSI protocol of the same
name, it provides an “arbitrate and win”
scenario among more than two devices when
those devices want to communicate on the
bus. The sending device must arbitrate and
win the connection with the receiving device
before communication can begin.
Arbitrated Loop Physical Address A one-
byte value that identifies a port in an
arbitrated loop topology.
ASIA Application specific interface adapter.
The interface card in the 9840 Tape Drive.
B
beginning-of-tape A point on the tape
where written data begins.
bin See Cartridge Scratch Loader (CSL)
block A string of data elements recorded or
transmitted as a unit. The elements may be
characters, words, or physical records. (T)
British thermal unit (Btu) A standard
measure of a device’s heat output. The
amount of heat required to raise one pound
of water one degree Fahrenheit.
Btu See British thermal unit.
buffer A routine or storage used to
compensate for a difference in rate of flow of
data, or time of occurrence of events, when
transferring data from one device to another.
(A)