Download Quantum DAT 24 Drive User's Guide

Page 38
DDS-4 SCSI Interface Manual, Rev. B
EXCHANGE MEDIUM (AutoLoader Only) (A6h)
The EXCHANGE MEDIUM command provides a means to exchange the cartridge
in the source element with the cartridge located in the drive. This command provides
the initiator a single-command alternative to two MOVE MEDIUM commands when
removing a cartridge from the DAT drive and inserting another cartridge into the
DAT drive.
EXCHANGE MEDIUM Command Descriptor Block
The following table shows the layout of the CDB.
Bits
Byte
7
6
5
4
3
2
1
0
0
1
0
1
0
0
1
1
0
0
0
0
0
0
1
LUN
2
0
0
0
0
0
0
0
0
3
0
0
0
0
0
0
0
0
4
0
0
0
0
0
0
0
0
5
Source Address
6
0
0
0
0
0
0
0
0
7
0
0
0
0
0
0
0
1
8
0
0
0
0
0
0
0
0
9
Source Destination
10
0
11
vendor unique*
0
0
0
0
0
0
0
0
0
0
0
Flag
Link
* This vendor-unique field is reserved and must be set to zero.
Command Descriptor Block Field Descriptions
The source address field specifies the location from which the cartridge is taken; the
destination address field specifies the location to which the cartridge is moved.
The destination address must represent an empty storage element; the cartridge in
the drive is first moved to this location. The source address must represent a full
storage element; this cartridge is then moved to the drive.
The following table shows the addresses of the various elements.
Source/
Destination
Address
Source/
Destination Element
0
0
1
Drive
2
Magazine slot 1
3
Magazine slot 2
4
Magazine slot 3
5
Magazine slot 4
6
Magazine slot 5
7
Magazine slot 6