Seagate ST19171WC Product Manual - Page 44

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34 Barracuda 9 Product Manual, Rev. C Table 4: Read and write retry count maximum recovery times Read retry Maximum recovery time count [1] per LBA (cumulative, msec) 0 42 1 67 2 92 3 125 4 184 5 217 6 267 7 367 8 400 9 450 10 525 11 675 12 884 13 1384 14 2384 15 3384 16 (default) 3534 Write retry Maximum recovery time count [1] per LBA (cumulative, msec) 0 42 1 67 2 92 3 142 4 175 5 184 6 217 7 267 8 342 9 442 10 942 11 1942 12 (default) 2942 [1] Setting these retry counts to a value below the default setting could result in degradation of the unrecovered error rate below the product specification. For example, suppose the read/write recovery page has the RC bit = 0, the read retry count set to 4, and the recovery time limit set to 450. A 4-block read command can take up to 184 msec recovery time for each block and a maximum of 450 msec recovery for all 4 blocks. If either of these limits is reached and a block has not yet been recovered, the command will end with CHECK CONDITION status and an unrecoverable read error will be reported. 7.3 SCSI systems errors Information on the reporting of operational errors or faults across the interface is given in the SCSI Interface Product Manual, part number 77738479. Message Protocol System is described in the SCSI Interface Product Manual. Several of the messages are used in the SCSI systems error management system. The Request Sense command returns information to the host about numerous kinds of errors or faults. The Receive Diagnostic Results reports the results of diagnostic operations performed by the drive. Status returned by the drive to the Initiator is described in the SCSI Interface Product Manual. Status reporting plays a role in the SCSI systems error management and its use in that respect is described in sections where the various commands are discussed.

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34
Barracuda 9 Product Manual, Rev. C
[1]
Setting these retry counts to a value below the default setting could result in degradation of the unrecov-
ered error rate below the product specification.
For example, suppose the read/write recovery page has the RC bit = 0, the read retry count set to 4, and the
recovery time limit set to 450. A 4-block read command can take up to 184 msec recovery time for each block
and a maximum of 450 msec recovery for all 4 blocks. If either of these limits is reached and a block has not
yet been recovered, the command will end with CHECK CONDITION status and an unrecoverable read error
will be reported.
7.3
SCSI systems errors
Information on the reporting of operational errors or faults across the interface is given in the
SCSI Interface
Product Manual,
part number 77738479. Message Protocol System is described in the
SCSI Interface Product
Manual
. Several of the messages are used in the SCSI systems error management system. The Request
Sense command returns information to the host about numerous kinds of errors or faults. The Receive Diag-
nostic Results reports the results of diagnostic operations performed by the drive.
Status returned by the drive to the Initiator is described in the
SCSI Interface Product Manual
. Status reporting
plays a role in the SCSI systems error management and its use in that respect is described in sections where
the various commands are discussed.
Table 4:
Read and write retry count maximum recovery times
Read retry
count [1]
Maximum recovery time
per LBA (cumulative, msec)
Write retry
count [1]
Maximum recovery time
per LBA (cumulative, msec)
0
42
0
42
1
67
1
67
2
92
2
92
3
125
3
142
4
184
4
175
5
217
5
184
6
267
6
217
7
367
7
267
8
400
8
342
9
450
9
442
10
525
10
942
11
675
11
1942
12
884
12 (default)
2942
13
1384
14
2384
15
3384
16 (default)
3534