Quantum 10K II - Manual (Page 238)

SCSI Description
Quantum Atlas 10K II Ultra160/m SCSI Hard Disk Drives 5–171
5.34 REQUEST SENSE Command (03h)
The REQUEST SENSE command causes the drive to transfer detailed sense data to
the initiator. The drive maintains sense data on an individual initiator basis.
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation Code (03h)
1 - 3 Reserved
4 Allocation Length
5 Control
Figure 5–84 REQUEST SENSE Command Descriptor Block — Data Format
Table 5–82 REQUEST SENSE Command Descriptor Block—Field Description
Field Description
Allocation Length The drives can return a maximum of 18 bytes of sense data. The initiator
should set this field to the maximum value to receive all the sense data.
5.34.1 Sense Data Availability
Sense data is available if the initiator is responsible for an in-progress FORMAT
UNIT command (Format Progress Indication is available in the Format Progress
Indication Bytes).
The drive returns a sense key of NO SENSE and an additional sense code of NO
ADDITIONAL SENSE INFORMATION if it has no sense data available for the
initiator.
For Parallel SCSI disk drives, sense data is available if the previous command from
the initiator terminated with a CHECK CONDITION status, or if the previous
command from the initiator ended with an unexpected BUS FREE error.