HP A3716A DDS-3 Autoloader User's Manual - 3716-96001
Glossary-2
DCLZ
Data Compression Lempel-Ziv. A compression algorithm based on the
Lempel-Ziv LZ2/LZW algorithms but with improved performance.
DDS
Digital Data Storage formats are industry-standard recording formats that
build on the DAT format to support the storage of computer data. The first
generation standard is DDS-1 (or simply DDS), to which was added data
compression to produce the DDS-DC standard. Further enhancements,
notably narrower tracks and thinner, longer tape, led to DDS-2, with
typically twice the capacity of DDS-1. DDS-3 uses a new magnetic coating
on the tape that allows twice the recording density. Together with the use
of time-tracking, this gives a DDS-3 cartridge approximately three times the
capacity of a DDS-2 cartridge.
decompression
A procedure in which codewords in compressed data are transformed to
regenerate the original representation of data.
ECMA
European Computer Manufacturers Association. The European equivalent
of ANSI.
EOD
End Of Data. An area in a partition that signifies the end of the valid data.
Each partition in a 2-partition tape has its own EOD.
EOM
End Of Media format. The last usable point on the tape.
EOP
End Of Partition. The position at the end of the permissible recording region
of a partition.
EW
Early Warning. A physical mark or a position on the tape computed by the
drive that tells the drive that it is approaching EOP.
fast-search
The process of reading just the sub-areas on a tape to locate an item at
speeds up to 100 times the normal read speed.
HBA
Host Bus Adapter. See host adapter.
host
The computer or computer system that controls the tape drive.
host adapter
A card that slots into a computer system providing a link between an
external bus and internal communication pathways. A SCSI host adapter
has connectors for SCSI cables and usually provides termination for the bus
at the computer end. Many servers have SCSI capability built into the main
system board, so they do not need a SCSI host adapter.
load
The process in which the changer mechanism inserts a cartridge into the
drive mechanism. The drive takes the cartridge, threads the tape, performs
a load sequence and goes online.
LUN
Logical Unit Number, by which different devices at a particular SCSI ID can
be addressed individually. In an autoloader, the drive is LUN 0 and the
changer mechanism is LUN 1.