Commands; The Command Descriptor Block; Table 4-1: Typical Six-Byte Command Descriptor Block; Table 4-2: Typical Ten-Byte Command Descriptor Block - Tandberg Data SLR7-140 PROGRAMMER Manual

4.
BYTE BIT 7
00 Operation Code
01 Logical Unit Number (LUN)
02 Parameters
03 Parameters
04 Parameters
05 Control Byte
Table 4-1:
BYTE BIT 7
00 Operation Code
01 Logical Unit Number (LUN)
02 Parameters
03 Parameters
04 Parameters
05 Parameters
06 Parameters
07 Parameters
08 Parameters
09 Control Byte

Table 4-2: Typical Ten-byte Command Descriptor Block

Operation Code

Commands

4.1.

The Command Descriptor Block

A request to the Drive is performed by sending a Command
Descriptor Block.
accompanied by a list of parameters sent during the DATA-
OUT phase.
The Drive will support Group 0 and Group 1 commands [2],
[3], [4], [7]. Group 0 commands have 6 bytes in the Command
Descriptor Block. Group 1 commands have 10 bytes in the
Command Descriptor Block.
Examples of Six-Byte and Ten-Byte Command Descriptor Blocks
are shown in the two following tables:
6 5
Typical Six-byte Command Descriptor Block
6 5
The Command Descriptor Block always has an operation
code as the first byte of the command. See Section 4.4.
for operation codes supported by the Drive.
4-1 Tandberg SLR Product Line SCSI Functional Specifications
For some commands
4 3
Parameters
4 3
Parameters
the request
2 1 0
2 1 0
is