Dell PowerVault TL4000 - Manual (Page 284)

compression
The process of eliminating gaps, empty fields, redundancies, and
unnecessary data to shorten the length of records or blocks.
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 that is 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.
control path drive
controllerA device that provides the interface between a system and one or
more tape drives.control path drive A drive that communicates messages
from the host computer to the library in which the drive is installed.
cookie A packet of data that is exchanged between the library and a web browser
to track configuration.
CP Circuit protector.
CPF Control Path Failover.
CRU Customer Replaceable Unit.
CSA Canadian Standards Association.
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 cartridge
A tape cartridge that is dedicated to storing data. Contrast with cleaning
cartridge.
data check
A synchronous or asynchronous indication of a condition that is caused by
invalid data or incorrect positioning of data.
dc Direct current.
DCS Designated Cleaning Slot.
degauss
To make a magnetic tape nonmagnetic by using electrical coils that carry
currents that neutralize the magnetism of the tape.
I-4 Dell PowerVault TL2000 Tape Library and TL4000 Tape Library User's Guide