User Manual

SCSI Commands Reference Manual, Rev. J 153
www.seagate.com Direct Access Block commands (SPC-5 and SBC-4)
BUFFER SOURCE field
If the SUPPORTED BUFFER ID field is set to 10h to EFh, the BUFFER SOURCE field (see table 117) indicates the source field the error history buffer
indicated by the SUPPORTED BUFFER ID field. If the SUPPORTED BUFFER ID field is set to 10h to EFh, the BUFFER SOURCE field should be
ignored by the application client.
MAXIMUM AVAILABLE LENGTH
The MAXIMUM AVAILABLE LENGTH field indicates the maximum number of data bytes contained in the buffer indicated by the SUPPORTED
BUFFER ID field. The actual number of bytes available for transfer may be smaller.
3.20.8.3 Error history data buffer
3.20.8.3.1 Overview
Unless an error is encountered, the device server shall return parameter data that contains error history from the error history
snapshot from the specified buffer at the specified buffer offset. The parameter data shall be formatted as indicated by the
BUFFER FORMAT field in the error history directory entry (see table 115) associated with the buffer ID specified by the READ
BUFFER command.
If the device server receives a READ BUFFER command with the MODE field set to 1Ch from the established error history I_T
nexus and the BUFFER ID field is set to a value that the error history directory (see 3.20.8.2) shows as not supported, then the
device server shall be terminate the command with CHECK CONDITION status with the sense key set to ILLEGAL REQUEST and
the additional sense code set to INVALID FIELD IN CDB.
If the value in the BUFFER OFFSET field is not supported, the device server shall terminate the command with CHECK CONDITION
status with the sense key set to ILLEGAL REQUEST and the additional sense code set to INVALID FIELD IN CDB.
The amount of error history in the specified buffer shall be less than or equal to the number of bytes indicated by the MAXIMUM
AVAILABLE LENGTH field in the error history directory (see 3.20.8.2).
3.20.8.4 Clear error history I_T nexus
If the BUFFER ID field is set to FEh, the device server shall:
a) clear the error history I_T nexus, if any; and
b) not transfer any data.
3.20.8.5 Clear error history I_T nexus and release snapshot
If the BUFFER ID field is set to FFh, the device server shall:
a) clear the error history I_T nexus, if any,
b) release the error history snapshot, if any; and
c) not transfer any data.
Table 117 BUFFER SOURCE field
Code Description
0h
The source is indicated in the EHS_SOURCE field in the error history directory (see table 112).
1h
The source is unknown.
2h
The error history information was:
a) created by the device server as the result of a vendor specific event; and
b) not created due to processing of a READ BUFFER command.
3h
The error history information was created due to the processing of the current READ BUFFER command.
4h
The error history information was created due to the processing of a previous READ BUFFER command.
All others
Reserved