MPE/iX Glossary of Terms and Acronyms (32650-90887)

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Glossary of Terms
bus address A number that is part of the address used to find a particular device. The
bus address is determined by a setting on a peripheral device that allows
the computer to distinguish between two devices connected to the same
interface. A bus address is also referred to as a device address.
BYE An MPE command used to terminate an interactive session on the HP
3000.
byte A combination of eight consecutive bits treated as a unit. A byte represents
one letter or number. The size of memory and disk storage is measured in
bytes.
bytes per inch (BPI) A measurement of data density; usually for tapes. It expresses the
number of bytes recorded per inch of recording surface.
C A high-level computer programming language that can do low-level
manipulations. It allows great flexibility with type declarations.
cable A connector between computers and peripheral devices.
cache A small, high-speed memory buffer unit. The cache is continually updated
to contain recently accessed data to reduce access time. There may be one
cache or separate caches for instructions and data. HP Precision
Architecture has separate caches.
cache miss When an instruction or data required by the CPU is not stored in a cache,
the procedure that occurs is called a cache miss. The required code or data
is then retrieved from the main memory modules.
capability A type of access right assigned to a subject (user, group, or account)
affecting what the subject can do to an object (file, device, command) on the
system.
card A printed circuit assembly (PCA). See board.
card cage The structure used to hold cards in their proper place inside the computer.
Card cage and I/O bay are sometimes used interchangeably. However, the
I/O bay usually refers to the entire cabinet containing one or more card
cages used to store the cards that control I/O devices.
card image The representation of data in the standard columns found on a punched
card, which is a fixed-length record of 80 characters.
carriage-control characters (CCTL) Carriage-control characters determine such
things as double spacing, vertical line spacing, and page ejects.
catalog A file that acts as a directory of specific objects (files, commands, messages,
users, etc.) on the system.
catenet Several networks that are joined, or concatenated, to form a network of
networks. A catenet is also called an internetwork.
cathode ray tube (CRT) The video display part of a terminal or PC.
CCITT Comite Consultatif International Telephonique et Telegraphique
(International Telegraph and Telephone Consultative Committee); an
international standards group for establishing communication protocols.