150 Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E
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The Enable Early Recovery (EER) bit, when set to one, allows the disc drive to apply on-the-fly T>1 ECC
correction as soon as possible, before attempting other retry mechanisms, and without reporting suc-
cessful corrections to be host as recovered error. 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
disc drive shall apply ECC correction before other retry mechanisms, but shall not perform T>1 correc-
tions on the fly; any successful correction will be reported to the host as a recovered error.
The Post Error (PER) bit, when set to one, indicates the disc drive reports Check Condition status and
appropriate 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.
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 disc 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.
The Disable Correction (DCR) bit, when set to one, indicates ECC correction shall not be applied to the
data even if correction is possible. When set to zero, ECC correction shall be applied if correction is
possible.
[4] The Retry Count is the maximum number of times the disc drive attempts its read recovery algorithms. A
Retry Count of zero inhibits non-ECC retries from being performed.
[5] The Correction Span is the size of the largest read data error, in bits, on which ECC correction is to be
attempted. Errors longer than this span are reported as unrecoverable. This value is drive dependent. If
this field is zero the drive uses its default value.
[6] The disc drive Head Offset Count is a default of zero and not changeable to signify that this feature is not
programmable by the initiator. Head offsets are performed as part of the disc drive’s retry algorithms.
[7] The disc drive Data Strobe Offset Count is a default of zero and not changeable to signify that this feature
is not programmable by the initiator. Data Strobe Offsets are performed as part of the disc drive’s retry
algorithms.
[8] The write retry count field specifies the maximum number of times that the target shall attempt its recov-
ery algorithm during write operations.
[9] Recovery Time limit in milliseconds. A hex FFFF indicates that the Recovery Time Limit is unlimited.
[10] In SCSI-1 mode of operation, this byte is the recovery time limit value (see [9] above).
