User Manual

SCSI Commands Reference Manual, Rev. J 160
www.seagate.com Direct Access Block commands (SPC-5 and SBC-4)
3.24 READ DEFECT DATA (10) command
3.24.1 READ DEFECT DATA (10) command overview
The READ DEFECT DATA (10) command (see table 126) requests that the device server transfer the medium defect data to the
data-in buffer.
If the device server is unable to access the medium defect data, it shall terminate the command with CHECK CONDITION status.
The sense key shall be set to either MEDIUM ERROR, if a medium error occurred, or NO SENSE, if medium defect data does not
exist. The additional sense code shall be set to DEFECT LIST NOT FOUND.
REQ_PLIST (request primary defect list) bit
0 A request primary defect list (REQ_PLIST) bit set to zero specifies that the device server shall not return the PLIST.
1 A REQ_PLIST bit set to one specifies that the device server shall return the PLIST, if any.
REQ_GLIST (request grown defect list) bit
0 A request grown defect list (REQ_GLIST) bit set to zero specifies that the device server shall not return the GLIST.
1 A REQ_GLIST bit set to one specifies that the device server shall return the GLIST, if any.
A REQ_PLIST bit set to zero and a REQ_GLIST bit set to zero specifies that the device server shall return only the defect list header
(i.e., the first four bytes of the defect list).
A REQ_PLIST bit set to one and a REQ_GLIST bit set to one specifies that the device server shall return both the PLIST and GLIST,
if any. The order the lists are returned in is vendor-specific. Whether the lists are merged or not is vendor-specific.
DEFECT LIST FORMAT field
The DEFECT LIST FORMAT field specifies the preferred format for the defect list. This field is intended for those device servers capable of return-
ing more than one format, as defined in the FORMAT UNIT command (see 3.3.5). A device server unable to return the requested format shall
return the defect list in its default format and indicate that format in the DEFECT LIST FORMAT field in the defect list header (see table 126).
If the requested defect list format and the returned defect list format are not the same, the device server shall transfer the defect data and then
terminate the command with CHECK CONDITION status with the sense key set to RECOVERED ERROR and the additional sense code set to
DEFECT LIST NOT FOUND.
ALLOCATION LENGTH field
The ALLOCATION LENGTH field is defined in 2.2.6. The application client is responsible for comparing the allocation length requested in the
CDB with the defect list length returned in the parameter data to determine whether a partial list was received. If the number of address
descriptors the device server has to report exceeds the maximum value that is able to be specified in the ALLOCATION LENGTH field, the device
server shall transfer no data and return CHECK CONDITION status with the sense key set to ILLEGAL REQUEST and the additional sense code set
to INVALID FIELD IN CDB.
Table 126 READ DEFECT DATA (10) command
Bit
Byte
7 6 5 4 3 2 1 0
0 OPERATION CODE (37h)
1 Reserved
2 Reserved REQ_PLIST REQ_GLIST DEFECT LIST FORMAT
3
Reserved. . .
6
7 (MSB)
ALLOCATION LENGTH
8 (LSB)
9 CONTROL