Dell PowerVault TL2000 - Manual (Page 97)

TEST UNIT READY (00h)
TEST UNIT READY checks if the media changer is ready for commands involving cartridge movement. If
the media changer has completed initialization and the magazines are inserted, the command returns
Good Status. Otherwise, Check Condition is reported. Due to power cycle, code update, etc., it is possible
to get multiple check conditions on TEST UNIT READY commands.
Bit 7 6 5 4 3 2 1 0
Byte
0 Operation Code (00h)
1 LUN Reserved
2 Reserved
3 Reserved
4 Reserved
5 Control
Field descriptions:
Chapter 3. Supported SCSI Commands 3-83