SCSI Commands
Page
33
LOAD UNLOAD
The Load Unload command may be used to load or unload a cartridge. This
command may also be used to request that the retension function be performed.
Command Descriptor Block
Byte
Bits
7
6
5
4
3
2
1
0
0
Operation Code (1Bh)
1
Ignored LUN Reserved
Immed
2
Reserved
3
Reserved
4
Reserved
Hold
EOT
Reten
Load
5
Control
Field Descriptions
Field
Bytes
Bits
Description
Operation
Code
0
The Operation Code for the Load Unload command is 1Bh.
Ignored
Logical
Unit
1
5-7
The LUN field is residual from the SCSI-1 days and is ignored.
Immed
1
0
0 = Status is not returned until the operation has completed.
1 = Status is returned as soon as buffered data, filemarks have
been written to the medium and the CDB has been validated.
Hold
4
3
1 = Requests that the medium be positioned to the Medium Auxil-
iary Memory Accessible position where the medium is seated
into the drive but the tape is not threaded to BOT.
EOT
4
2
Not supported. Must be set to 0.
Reten
4
1
1 = Requests that the retension function be performed on medium.
Load
4
0
0 = requests that the medium be unloaded.
1 = requests that the medium be loaded.
Reserved
All reserved bits must be 0.
Control
5
See Control Byte Format on page 18.
The drive has three possible states where the medium may be positioned. The
locations are:
•
The Medium Loadable Position where the medium is inserted into the drive but
has not been seated into the drive and the tape has not been threaded to BOT.
•
The Medium Auxiliary Memory Accessible Position where the medium has been
seated into the drive but the tape has not been threaded to BOT.
•
The Medium Loaded And Ready Position where the medium has been seated
into the drive and the tape has been threaded to BOT. The medium is ready to
use.
