User's Guide

Chapter 3 Emulated DLT7000 SCSI Commands
Prevent / Allow Medium Removal (1Eh)
228 Quantum DX-Series Software Interface Guide
Table 177 PREVENT
/ ALLOW MEDIUM
REMOVAL Command
Descriptor Block -
Field Descriptions
Field Name Description
Prevent The PREVENT / ALLOW status in the device is
maintained separately by each initiator.
When set to 0, the prevent state corresponding to
that initiator is cleared. When all initiators have
cleared their prevent states, the UNLOAD button
and UNLOAD commands are enabled. By default,
after power up, a hard reset, or Bus Device Reset
message, the prevent medium removal function is
cleared.
If a Media Loader device is present, its MOVE
MEDIUM command is prevented from removing a
cartridge if PREVENT has been enabled.
Flag Bit The Flag bit is used in conjunction with the Link bit
to notify the initiator in an expedient manner that a
command has been completed.
Flag bits are not supported by the DX-Series system.
Link Bit A Link bit set to 1 indicates that the initiator
requests continuation of a task (an I/O process)
across two or more SCSI commands.
If the Link bit is 1 and the Flag bit is 0, and the task
completes successfully, the drive continues the task
and returns a status of INTERMEDIATE and a
LINKED COMMAND COMPLETE message.
If the Link bit and the Flag bit within a Control
word are both set to 1, and the drive completes a
command with a status of INTERMEDIATE, the
drive returns a LINKED COMMAND COMPLETE
message (with Flag).
Link bits are not supported by the DX-Series
system.