Tandberg Data SDLT220, Руководство по эксплуатации продукта

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Glossary
D
Data
Compression A process that reduces the amount of storage space required to
hold a particular block of data. Data transfer speed and total tape
capacity are affected by the data compression achieved. In
accordance with industry practice, a typical compression ratio is
2:1 of data storage. Actual compression ratios achieved depend
on the redundancy of data files being written.
DC Direct Current.
DCM Data Control Module. The DCM contains several of the
functions and features of Quantum’s LGMR technology, which is
at the heart of the SDLT technology. Of the five technologies that
constitute the LGMR technology, two are found in the DCM.
These are the POS and the MRC heads. The main functions of
the DCM are to provide the path and guides for the all tape
motion inside the drive and to write data to and read data from
the tape.
Device According to the SCSI specification, up to eight SCSI devices
can be connected to a single SCSI bus. Each SCSI device
contains a SCSI ID number that can be set to 0-7.
Device Driver A low-level (usually kernel-mode) operating system component
that enables a PC to communicate with peripheral devices such as
fixed disk drives, CD-ROMS, and tape drives. Each kind of
device requires a different driver. Device driver programs are
loaded into memory at boot time.
Differential A term referring to the electrical characteristics of the signal used
on the SCSI bus interface. Differential signals minimize the
effect of common mode signal noise and allow the SCSI bus to
operate reliably over greater distances at a higher speed.
DLZ Digital Lempel-Ziv 1 Algorithm. Named after Abraham Lempel
and Jacob Ziv. A data compression technique used in all SDLT
tape drives.