Seagate Ultra 160 ユーザーズマニュアル

Parallel SCSI Interface Product Manual, Rev. A                                        

   135

See notes following Table 61.

Notes for Tables 57, 58, 59, 60, and 61.

[1] The Operation Code field of the Command Descriptor Block contains the code value indentifying the oper-

ation being requested by the CDB. The Operation Code provides for a possible 256 command operation 
codes. Details of the various commands with their operation codes are defined in Section 8.0 of this man-
ual.

[2] Service Action. All typical CDB formats except the typical 6-byte format provide for a Service Action field 

containing a coded value identifying a function to be performed under the more general command func-
tion specified in the Operation Code field. While the Service Action field is defined for typical CDB formats, 
it is used as described in this clause only in those CDB formats that explicitly contain a Service Action 
field. When the specific field Service Action is not defined in a CDB format, the bits identified as the Ser-
vice Action field in a typical CDB may be used for other purposes. More details appear on this in Section 

(MSB)

TRANSFER LENGTH (If required) [4]

PARAMETER LIST LENGTH (if required) [5]

ALLOCATION LENGTH (if required) [6]

(LSB)

Reserved

CONTROL [7]

OPERATION CODE (7Fh) [1]

CONTROL [7]

Reserved

Reserved

Reserved

ENCRYPTION IDENTIFICATION [8]

Reserved

ADDITIONAL CDB LENGTH (n–7) [9]

(MSB)

SERVICE ACTION [2]

(LSB)

SERVICE ACTION SPECIFIC FIELDS [10]