Quantum DLTtape DLT 4000, Product Manual

Page: 56 / 300

Hardware Implementation
2-22 Quantum DLT 4000 Tape Drive
2.5.2 Selecting Density
This subsection describes the drive’s density select features.
CAUTION
If a prerecorded tape is reused and a WRITE from the beginning of
tape (BOT) executes (No Append Write), any data already recorded
on the tape will be lost. This includes density changes, since they
occur only when writing from BOT.
NOTES
On all READ and all WRITE APPEND operations, the data density that
already exists on the tape cartridge remains the density.
Default density of a DLTtape TM III cartridge is 10.0 GB, native. The
only optional selections for DLTtape III cartridges are 2.6 GB, 6.0 GB,
10.0 GB (compression OFF), or 20.0 GB (compression ON).
Default density of a DLTtape IIIxt cartridge is 15.0 GB, native
(compression OFF), or 30.0 GB (compression ON). No other density is
supported.
Default density of a DLTtape IV cartridge is 20.0 GB, native
(compression OFF). A density of 40.0 GB is user-selectable. No other
density is supported.
When writing from BOT, tape density may be changed by:
•
Using the Density Select Button on the front panel of the tape drive. Using
the Density Select Button always overrides density selection via the host.
•
Using the operating system to issue a density designation. In this case, the
amber Density Override LED on the tape drive’s front panel turns off,
indicating an automatic or host density selection.
•
Native default density for the DLTtape IV is 20.0 GB. The only available
option is compression on or off.