Optical Drive and Library SCSI-2 Command Reference

SCSI-2 Drive Command Set
Request Sense Command (03H)
Chapter 22-10
Request Sense Command (03H)
This command determines the specific error condition when a drive fails
to complete a command and returns a CHECK CONDITION status.
Sense data is preserved for the initiator until retrieved by a Request
Sense Command or until the same drive receives another command.
Internal Error Codes are used to represent the error condition and can be
used to determine what type of error recovery procedure is appropriate.
The Allocation Length indicates the number of bytes of sense data that
the drive transfers to the initiator. This drive has 22 bytes of sense data.
If an allocation length specified is less, then the allocated amount is
transferred, the remaining sense data is lost, and no error will be
reported. If an allocated length specified is greater, then only 22 bytes of
sense data are transferred and no error will be reported.
Table 2-6 Request Sense Command CDB
Byte 7 6 5 4 3 2 1 0
0 Operation Code (03H)
1 Logical Unit Number
(0)
Reserved (0)
2 Reserved (0)
3 Reserved (0)
4 Allocation Length (Table 2-7 on page 2-11)
5 Reserved (0) Flag Link