Product manual

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)
042 042
167 167
292 292
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