User's Guide

Commands: Request Sense (03h) Page 133
REQUEST SENSE (03h)
The REQUEST SENSE command causes the drive to transfer status data to the
Initiator pertaining to the last command.
REQUEST SENSE Command Descriptor Block
The following table shows the layout of the CDB.
Byte
Bits
7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 1 1
1 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0
4 Allocation Length
5 vendor unique* 0 0 0 0 Flag Link
* This vendor-unique field is reserved and must be set to zero.
Sense Data is updated with each command; therefore, the sense data only reports
the status of the immediately previous command. If a Check Condition status
results, a REQUEST SENSE command should be issued to recover the information
form the Sense Data.
The REQUEST SENSE command returns Check Condition status only if a fatal
error occurs during execution of the REQUEST SENSE command. If nonfatal errors
occur during the REQUEST SENSE execution, Good Status is returned. Sense
Data may be invalid following a fatal error on a REQUEST SENSE command.
Sense Data Format
The following table shows the format for the sense data.
Byte
Bits
7 6 5 4 3 2 1 0
0 Valid Error Code
1 0 0 0 0 0 0 0 0
2 FM EOM ILI 0 | Sense Key
3 MSB—Residual Length (0)
4 Residual Length (0)
5 Residual Length (0)
6 Residual Length—LSB (0)
7 Additional Sense Length
8 0 0 0 0 0 0 0 0
9 0 0 0 0 0 0 0 0
10 0 0 0 0 0 0 0 0
11 0 0 0 0 0 0 0 0
12 Additional Sense Code
13 Additional Sense Code Qualifier
14 0 0 0 0 0 0 0 0