Technical information

HGST Ultrastar C15K600 Hard Disk Drive Specification
352
22
SCSI Sense Data
22.1
SCSI Sense Data Format Introduction
Sense data is returned as CHECK CONDITION status and as parameter data in response to the REQUEST SENSE
command. The sense data returned by the drive can be in either fixed or descriptor format
22.1.1
Sense Data Format
Format of sense data returned as a CHECK_CONDITION_STATUS is based on the value of the D_SENSE bit in the
Control mode page (See section 18.10.9 "Mode Page 0A"). The REQUEST SENSE command may be used to
request either the fixed format sense data or the descriptor format sense data (See section 18.36 "REQUEST
SENSE").
22.1.2
Sense Data Length
Length of the sense data returned as part of CHECK_CONDITION status is determined by the sense data format:
a) Length of fixed format sense data is always 32 byte.
b) Length of descriptor format sense data is 60 byte (Generic Configuration)
For REQUEST SENSE command, length of the sense data is the number of bytes in the command’s Allocation
Length or the sense data length described above, whichever is less.
22.1.3
Sense Data Response Code
The first byte of all sense data contains the RESPONSE CODE field that indicates the error type and format of the
sense data. Table 295“Sense data response codes.” shows the RESPONSE CODE values which may be returned
by the drive
Table 304 Sense data response codes
Response Code
Error Type
Sense Data Format
70h
Current
Fixed
71h
Deferred
Fixed
72h
Current
Descriptor
73h
Deferred
Descriptor
Current Error: This indicates an error for the current command.
Deferred Error: This indicates that the error is for a previous command that has already returned a good status.
Such commands are associated with the immediate bit or write caching. Format unit (04h) command is an example
of a command that may return a deferred error.