Commands148
Request Sense data
Sense data is recovered from the drive by means of a REQUEST SENSE command following the
reporting of
CHECK CONDITION by the drive. There are two formats in which the data can be
returned: Fixed and Descriptor.
Fixed format
The Fixed format of the returned data is as follows:
Returned Sense data fields:
Allocation
Length
0 No data is transferred to the host.
>0 The maximum amount of sense data in bytes that should be transferred to the host.
The drive returns up to Allocation Length bytes of data; any extra sense data is lost.
7 6 5 4 3 2 1 0
0 Valid Error Code
1 Segment Number (0)
2 Mark EOM ILI Rsvd(0) Sense Key
3 (MSB)
Information Bytes
6 (LSB)
7 Additional Sense Length (10h)
8 (MSB)
Command Specific Information Bytes
11 (LSB)
12 Additional Sense Code
13 Additional Sense Code Qualifier
14 Field Replaceable Unit Code
15 SKSV C/D Reserved (0) BPV Bit Pointer
16 (MSB)
Field Pointer/Drive Error Code
17 (LSB)
18–20 Reserved (0)
21 Reserved (0) CLN Reserved (0)
22
Pad bytes (0)
23
Valid 1 Indicates that the information bytes contain valid information as defined in
the SCSI specification.
Error Code 70h Indicates that the error is current, that is, it is associated with the command
for which
CHECK CONDITION status has been reported.
