User Manual

SCSI Commands Reference Manual, Rev. J 50
www.seagate.com General Concepts
DESCRIPTOR TYPE and ADDITIONAL LENGTH fields
The DESCRIPTOR TYPE and ADDITIONAL LENGTH fields are described in 2.4.1.1.1. For the command-specific information sense data descriptor,
the DESCRIPTOR TYPE field shall be set to 01h and the ADDITIONAL LENGTH field shall be set to 0Ah.
COMMAND-SPECIFIC INFORMATION field
The COMMAND-SPECIFIC INFORMATION field contains information that depends on the command on which the exception condition occurred.
When a four byte quantity is stored in the COMMAND-SPECIFIC INFORMATION field, the first four bytes shall be zero.
Further meaning for the COMMAND-SPECIFIC INFORMATION field is defined within the command description in the appropriate command
standard (e.g., see SBC-4 for the REASSIGN BLOCKS commands, or SPC-5 for the EXTENDED COPY command).
2.4.1.1.4 Sense key specific sense data descriptor
2.4.1.1.4.1 Sense key specific sense data descriptor introduction
The sense key specific sense data descriptor (see table 17) provides additional information about the exception condition. The
format and content of the sense-key specific data depends on the value in the SENSE KEY field (see 2.4.1.1.1).
DESCRIPTOR TYPE and ADDITIONAL LENGTH fields
The DESCRIPTOR TYPE and ADDITIONAL LENGTH fields are described in 2.4.1.1.1. For the sense-key specific sense data descriptor, the DESCRIP-
TOR TYPE field shall be set to 01h and the ADDITIONAL LENGTH field shall be set to 06h.
SKSV (Sense-key specific valid) bit
The sense-key specific valid (SKSV) bit shall be set to one.
NOTE In the fixed format sense data, the SKSV bit indicates whether the contents of the SENSE KEY SPECIFIC
field are valid as defined by a command standard. Since the contents of the SENSE KEY SPECIFIC field
are valid whenever a sense key specific sense data descriptor is included in the sense data, the only
legal value for the SKSV bit is set to one.
Table 17 Sense key specific sense data descriptor format
Bit
Byte
7 6 5 4 3 2 1 0
0
DESCRIPTOR TYPE (02h)
1
ADDITIONAL LENGTH (06h)
2
Reserved
3
Reserved
4
SKSV (1b)
SENSE KEY SPECIFIC
5
6
7
Reserved