Hitachi HUS154530VLF400 User Manual

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Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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19.32.1  All_commands parameter data format
The Report Supported Operation Codes all_command parameter data format begins with a four-byte header that contains the 
length in bytes of the parameter data, followed by a list of supported commands.  Each command descriptor contains informa-
tion about a single supported command CDB (i.e. one operation code and service action combination, or one non-service-
action operation code).
Each Command Descriptor contains information about a single supported command CDB.
Operation Code contains the operation code of a supported command.  
Service Action contains a supported serivce action of the supported operation. If the operation code does not have a service 
action, the Service Action field will be set to zero.
SERVACTV  set to zero indicates the operation code does not have service actions and the Service Action field should be 
ignored.  SERVACTV set to one indicates the operation code field has service actions and the contents of the Service Action 
field are valid.
CDB Length contains the length of the command CDB in bytes.
Byte
Bit
7
6
5
4
3
2
1
0
0-3
Command Data Length (n-3)
4
Command Descriptor 0
N
Command Descriptor X
Byte
Bit
7
6
5
4
3
2
1
0
0
Operation Code
1
Reserved = 0
2-3
Service Action
4
Reserved = 0
5
Reserved = 0
SERVACTV
6-7
CDB Length