Table 23 - Typical command descriptor block for twelve-byte commands
Bit
Byte
 7 6 5 4 3 2 1 0
0 Operation code
1 Logical unit number Reserved
2
--
5
(MSB)
---|
Logical block address (if required)
---|
(LSB)
6
--
9
(MSB)
---|
Transfer length (if required)
Parameter list length (if required)
Allocation length (if required)
---|
(LSB)
10 Reserved
11 Control