IBM Magstar MP 3570 C Series, Информация по обслуживанию

Страница: 618 / 675

channel command. An instruction that directs a data
channel, control unit, or device to perform an operation
or set of operations.
char. Character.
CHK. Check.
cm. Centimeter.
command. A control signal that initiates an action or
the start of a sequence of actions.
concurrent. Refers to diagnostic procedures that can
be run on one control unit while the rest of the
subsystem remains available for customer applications.
contingent connection. A connection between a
channel path and a drive caused when a unit check
occurs during an I/O operation.
controller. A device that provides the interface
between a system and one or more tape drives.
CP. Circuit protector.
CRC. Cyclic redundancy check.
CRR. Channel request register.
ctrl. Control.
CU. Control unit.
D
danger (notice). A word to call attention to possible
lethal harm to people. Contrast with
attention and
caution.
data. Any representations such as characters or
analog quantities to which meaning is or might be
assigned.
data buffer. The storage buffer in the control unit.
This buffer is used to increase the data transfer rate
between the control unit and the channel.
data check. A synchronous or asynchronous
indication of a condition caused by invalid data or
incorrect positioning of data.
dc. Direct current.
degradation. A decrease in quality of output or
throughput or an increase in machine error rate.
degraded. Decreased in quality of output or
throughput or increased machine error rate.
deserialize. To change from serial-by-bit to
parallel-by-byte.
detented. A part being held in position with a catch or
lever.
DEV. Device.
DIAG. Diagnostic section of maintenance information
manual.
direct access storage. A storage device in which the
access time is independent of the location of the data.
DRAM. Dynamic random-access memory.
drive, magnetic tape. A mechanism for moving
magnetic tape and controlling its movement.
DRV. Drive.
E
EBCDIC. Extended binary-coded decimal interchange
code.
EC. Edge connector. Engineering change.
ECC. Error correction code.
EEPROM. Electrically erasable programmable
read-only memory.
EIA. Electronics Industries Association.
EIA unit. A unit of measure, established by the
Electronic Industries Association, equal to 44.45
millimeters (1.75 inches).
end-of-block (EOB). A code that marks the end of a
block of data.
end-of-file (EOF). A code that marks the end of a file
of data.
end-of-tape (EOT). The end of the recording area on
a tape.
EOB. End-of-block.
EOF. End-of-file.
EOT. End-of-tape.
EPO. Emergency power off.
EPROM. Erasable programmable read only memory.
EQC. Equipment check.
Gloss-2
IBM 3570 MI