307
Western Digital Hard Disk Drive OEM Specification
11.73
Write Uncorrectable Ext (45h)
Com m and Block Output Registers
Com m and Block Input Registers
Register
7
6
5
4
3
2
1
0
Register
7
6
5
4
3
2
1
0
Data Low
-
-
-
-
-
-
-
-
Data Low
-
-
-
-
-
-
-
-
Data High
-
-
-
-
-
-
-
-
Data High
-
-
-
-
-
-
-
-
Feature
Current
V
V
V
V
V
V
V
V
Error
...See Below ...
Previous
-
-
-
-
-
-
-
-
Sector Count
Current
V
V
V
V
V
V
V
V
Sector Count
HOB=0
-
-
-
-
-
-
-
-
Previous
V
V
V
V
V
V
V
V
HOB=1
-
-
-
-
-
-
-
-
Sector Number
Current
V
V
V
V
V
V
V
V
Sector Number
HOB=0
V
V
V
V
V
V
V
V
Previous
V
V
V
V
V
V
V
V
HOB=1
V
V
V
V
V
V
V
V
Cylinder Low
Current
V
V
V
V
V
V
V
V
Cylinder Low
HOB=0
V
V
V
V
V
V
V
V
Previous
V
V
V
V
V
V
V
V
HOB=1
V
V
V
V
V
V
V
V
Cylinder High
Current
V
V
V
V
V
V
V
V
Cylinder High
HOB=0
V
V
V
V
V
V
V
V
Previous
V
V
V
V
V
V
V
V
HOB=1
V
V
V
V
V
V
V
V
Device/Head
-
1
-
D
-
-
-
-
Device/Head
-
-
-
-
-
-
-
-
Command
0
1
0
0
0
1
0
1
Status
...See Below ...
Error Register
Status Register
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
CRC
UNC
0
IDN
0
ABT
T0N
AMN
BSY
RDY
DF
DSC
DRQ
COR
IDX
ERR
0
0
0
V
0
V
0
0
0
V
0
V
-
0
-
V
Table 264 Write Uncorrectable Ext Command (45h)
The Write Uncorrectable Ext command is used to cause the device to report an uncorrectable error when the target
sector is subsequently read.
When the Feature field contains a value of 55h the Write Uncorrectable Ext command shall cause the device to
indicate a failure when reads to any of the sectors that are contained in physical block of specified sector are
performed. These sectors are referred to as ‘pseudo uncorrectable’ sectors. In this case whenever a pseudo
uncorrectable sector is accessed via a read command the drive shall perform normal error recovery to the fullest
extent and then set the UNC and ERR bits to indicate the sector is bad.
When the Feature field(7:0) contains a value of AAh the Write uncorrectable ext command shall cause the device to
flag the
specified sector as ‘flagged uncorrectable’. Flagging a logical sector as uncorrectable shall cause the device
to indicate a failure when reads to the specified sector are performed. These sectors are referred to as ‘flagged
uncorrectable’ sectors. In this case whenever a ‘flagged uncorrectable’ sector is accessed via a read command the
device shall set the UNC and ERR bits to indicate the sector is bad.
If this command is sent to the device with the content of the Features field(7:0) set to anything other than what is
defined above the device shall abort the command.
Commands that return UNC and ERR when a pseudo uncorrectable or flagged uncorrectable sector is read include:
READ DMA, READ DMA EXT, READ MULTIPLE, READ MULTIPLE EXT, READ SECTOR(S), READ SECTOR(S)
EXT, READ VERIFY SECTOR(S), READ, VERIFY SECTOR(S) EXT, READ STREAM EXT, READ STREAM DMA
EXT. if the host writes to a ‘pseudo uncorrectable’ or ‘flagged uncorrectable’ sector, the drive shall attempt to write
the data to the sector. The write shall clear the uncorrectable status of the sector and make the sector good if
possible and the device shall verify that the sector may now be read without error. It is possible that an
‘uncorrectable’ sector location has actual physical errors. In this case read commands and/or write commands shall
return ERR status information that is consistent with the error. The pseudo uncorrectable or flagged uncorrectable
