User's Guide

Chapter 3 Emulated DLT7000 SCSI Commands
Load Unload (1Bh)
Quantum DX-Series Software Interface Guide 143
READY command, the drive returns a CHECK CONDITION STATUS
with a NOT READY sense key set.
The sequential loading feature of the loader can be enabled/
disabled by modifying the ENALDRAUTOLD and
DISLDRAUTOLDMC parameters of EEPROM (mode page
3Eh of the MODE SELECT command).
A media loader does not affect the tape drive’s processing of
the LOAD portion of the LOAD UNLOAD command.
Note: Operation of the UNLOAD version of this command is
different if a media loader is present.
Two modes of operation are possible if a media loader is
configured. If none of the media loader-specific commands
have been issued, the device operates in the sequential mode of
operation described below. Once a media loader-specific
command has been issued, however, the sequential mode of
operation is disabled and the UNLOAD command becomes a
NO OPERATION.
If the tape drive is in the default sequential mode of operation
and an UNLOAD command is received by the subsystem, the
current cartridge is unloaded and automatically moved to the
magazine slot from which it was received. The cartridge from
the next magazine slot (if the slot is not empty) automatically
moves from the magazine into the drive, is loaded, and made
ready. If the next magazine slot is empty, no CHECK
CONDITION status is created.
When the cartridge is unloaded into the last magazine slot, the
subsystem does not cycle back to slot 0. This prevents
accidental overwriting of data when using a media loader
subsystem in sequential auto-loading mode. The next cartridge
in the cycle must be selected and loaded manually, or with a
SCSI MOVE MEDIUM command.