Seagate SCSI Interface Product Manual page 147

SCSI Interface Product Manual, Rev. J
Notes.
[1] The Parameter Savable (PS) bit is used only with the Mode Sense command. This bit is reserved with the
Mode Select command. A PS bit of one indicates that the target is capable of saving the page in a non-
volatile vendor specific location.
[2] The Enable Early Recovery (EER) bit, when set to one, allows the drive to apply on-the-fly T>1 ECC cor-
rection as soon as possible, before attempting other retry mechanisms, and without reporting successful
corrections to the host as recovered errors. Seek error retries and message system errors are not affected
by this bit. When this bit is set, the DCR bit must be zero. When the EER bit is set to zero, the drive shall
apply ECC correction before other retry mechanisms, but shall not perform T>1 corrections on the fly; any
successful correction will be reported to the host as a recovered error.
[3] The Post Error (PER) bit, when set to one, indicates the drive reports Check Condition status and appro-
priate sense key for any recovered errors encountered. Reporting of unrecoverable errors has priority over
reporting of recoverable errors. When set to zero, any errors recovered within the limits established by the
other Error Recovery Flags are not reported. Any unrecoverable errors are reported.
[4] The Disable Transfer on Error (DTE) bit is valid only when the PER bit is set to one. When the DTE bit is
set to one, it indicates the drive terminates data transfer even for recoverable errors (the drive will transfer
the data for the recovered error before terminating the transfer). When DTE is set to zero, data transfer
continues if recoverable errors are encountered. If the PER bit is one and the DTE bit is zero, recoverable
errors are reported after all data has been transferred.
[5] The Disable Correction (DCR) bit, when set to one, indicates that only on-the-fly ECC correction shall be
applied. The exact behavior is product specific. When set to zero, maximum ECC correction shall be
applied if correction is possible.
[6] The Verify Retry Count sets up the maximum amount of error recovery effort to be applied for each LBA
that could not be recovered during a verify operation. The hex value in this field specifies the maximum
error recovery level that the drive applies during a verify operation to the recovery of an LBA needing
recovery effort. Each level may consist of multiple error recovery steps. See individual drive's Product
Manual, Volume 1, for more details on the levels of error recovery available.
[7] The Verify Correction Span field specifies the size (in bits) of the largest burst data error for which data
error correction may be attempted. If the drive does not implement this field, a value of zero is returned in
Mode Sense data.
[8] The Verify Recovery Time Limit field (bytes 10 and 11) specifies the maximum time in milliseconds that
the host allows the drive to spend in error recovery efforts during the execution of a command. The Verify
Retry count can also be set to limit the amount of time the drive spends in error recovery of individual
LBAs. The total of all times used to recover individual LBAs in the block called for by a command cannot
exceed the Recovery Time Limit value in bytes 10 and 11. Once the drive has reached the error recovery
time limit for a particular command, the command ends with a Check Condition status and an unrecov-
ered error is reported. A Recovery Time Limit of FFFFh means that the command recovery time is unlim-
ited. A value of 0000h means that no time shall be spent in error recovery. A changeable Recovery Time
Limit is not supported on all drives supported by this manual. See individual drive's Product Manual, Vol-
ume 1, Mode page changeable bit settings for Mode page 01h, bytes 10 and 11.
To disable all types of correction and retries, the initiator sets the EER bit to zero, the PER, DTE, and DCR
bits to one, and the number of retries and recovery time limit to zero.
[9] See individual drive's Product Manual, Volume 1, Mode Sense Data section, for changeable values.
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