User Manual

SCSI Commands Reference Manual, Rev. J 432
www.seagate.com Parameters for direct access devices
READ RETRY COUNT field
The READ RETRY COUNT field specifies the number of times that the device server shall attempt its recovery algorithm during read operations.
WRITE RETRY COUNT field
The WRITE RETRY COUNT field specifies the number of times that the device server shall attempt its recovery algorithm during write opera-
tions.
RECOVERY TIME LIMIT field
The RECOVERY TIME LIMIT field specifies in milliseconds the maximum time duration that the device server shall use for data error recovery
procedures. The device server may round this value as described in
2.3. The limit in this field specifies the maximum error recovery time
allowed for any individual command. A RECOVERY TIME LIMIT field set to zero specifies that the device server shall use its default value.
When both a retry count and a recovery time limit are specified, the field that specifies the recovery action of least duration shall
have priority.
To disable all types of correction and retries the application client should set the EER bit to zero, the PER bit to one, the DTE bit to
one, the DCR bit to one, the READ RETRY COUNT field to 00h, the WRITE RETRY COUNT field to 00h, and the RECOVERY TIME
LIMIT field to 0000h.
1 1 0 0 The device server shall perform the fewest possible number of retries and perform error correction in an attempt
to recover the data.
The device server shall terminate a command performing a read or write operation with CHECK CONDITION status
before the transfer count is exhausted only if an unrecoverable error is detected.
If an unrecoverable data error occurs during a read operation, the transfer block (TB) bit determines whether the
data for the logical block with the unrecovered read error is transferred to the data-in buffer
If a recovered error occurs while the device server is performing a read or write operation, then, after the
operation is complete, the device server shall terminate the command with CHECK CONDITION status with the
sense key set to RECOVERED ERROR. The INFORMATION field in the sense data shall contain the LBA of the last
recovered error that occurred during the command.
110 1
Invalid mode. The DCR bit shall be set to zero if the EER bit is set to one.
[a]
1 1 1 0 The device server shall perform the fewest possible number of retries and perform error correction in an attempt
to recover the data.
The device server shall terminate the command performing a read or write operation with CHECK CONDITION
status before the transfer count is exhausted if any error, either recoverable or unrecoverable, is detected. The
INFORMATION field in the sense data shall contain the LBA of the block in error.
If an unrecoverable data error occurs during a read operation, the transfer block (TB) bit determines whether the
data for the logical block with the unrecovered read error is transferred to the data-in buffer.
111 1
Invalid mode. The DCR bit shall be set to zero if the EER bit is set to one.
[a]
[a]If an invalid combination of the error recovery bits is sent by the application client the device server shall terminate the MODE
SELECT command with CHECK CONDITION status with the sense key set to ILLEGAL REQUEST and the additional sense code set to
INVALID FIELD IN PARAMETER LIST.
Table 405 Combined error recovery bit descriptions (Sheet 3 of 3)
EER PER DTE DCR Description