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.
Byte
Bits
7 6 5 4 3 2 1 0
0 1 0 1 0 0 1 1 0
1 LUN 0 0 0 0 0
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 0 0 0 0 0 0 0
11 vendor unique* 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