192
Western Digital Hard Disk Drive OEM Specification
Byte 3 contains the contents of the Error Register when the error occurred.
Byte (9:4) indicates the starting LBA of the error.
Byte (13:12) indicate the length of the error. Therefore, each entry may describe a range of sectors at the given
address and spanning the specified number of sectors.
11.23.8
Write Stream Error log
Table 168 defines the format of the Write Stream Error log. Entries are placed into the Write Stream Error log only
when the SE bit is set to one in the Status Register. The 512 bytes returned shall contain a max imum of 31 error
entries. The Write Stream Error Count shall contain the total number of Write Stream Errors detected since the last
successful completion of the Read Log Ext command with LBA Low register set to 21h. This error count may be
greater than 31, but only the most 31 errors are represented by entries in the log. If the Write Stream Error Count
reaches the maximum value that can be represented after the next error is detected the Write Stream Error Count
shall remain at the maximum value. After successful completion of a Read Log Ext command with the LBA Low
Register set to 21h, the Write Stream Error Log shall be reset to a power-on or hardware reset condition, with the
Error Log Index and Write Stream Error Count cleared to zero. The Write Stream Error Log is not reserved across
power cycles and hardware reset.
Description
Bytes
Offset
Structure Version
1
00h
Error Log Index
1
01h
Write Stream Error Log Count
2
02h
Reserved
12
04h
Write Stream Error Log Entry #1
16
10h
Write Stream Error Log Entry #2
16
20h
...
Write Stream Error Log Entry #31
16
1F0h
512
Table 168 Write Stream Error Log
The Data Structure Version field shall contain a value of 02h indicating the second revision of the structure format.
The Write Stream Error Log Count field shall contain the number of Write Stream command entries since the last
power on, since this log was last read, or since hardware reset was executed.
The Error Log Index indicates the error log data structure representing the most recent error. Only values (31:0) are
valid.
Table 166 defines the format of each entry in the Error Log.
