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Sense Data and Error Recovery Methods
5.2.3 Error logging
In order to collect information that is effective in maintenance, it is desirable for
the INIT to accumulate (log) error information related to the SAS interface which
it has detected itself (error frame detection, command completion wait time-out,
etc.) and error information reported by the IDD.
By specifying "1" in the PER bit in the "Read/Write Error Recovery parameter
(Page 1) and the "Verify Error Recovery parameter (Page 7) of the MODE
SELECT or MODE SELECT EXTENDED command, the INIT can know of the
occurrence of errors which were recovered from successfully by the IDD's
internal error recovery processing and their contents. By logging that error
information, the INIT can obtain data for more detailed analysis of the disk drive's
operating condition.
Concerning the contents of the error log, it is recommended that the data have a
time stamp affixed so that they can be edited in a time series of the times the
errors were detected, and that they include the following information.
•
The source which issued the command and the ID of the device which was
the target of the command.
•
The CDB which was issued.
•
The receiving status, or, when the status was that the command could not be
received, the code showing the type of error detected by the INIT and its
content.
•
All bytes reported by the IDD.
5.3 Disk Drive Error Recovery Processing
This section explains concerning error recovery processing methods and
procedures executed by the IDD for each type of disk drive related error. The
INIT can control the error recovery processing methods executed by the IDD
using the MODE SELECT parameters.
5.3.1 Error states and retry processing procedures
(1) Seek error
Mechanical malfunctions of the disk drive during a seek operation and failure of
serial addresses detected during verification of the ID area to match are included
in this error.
When a seek error occurs, the IDD first executes rezero seek, then tries
repositioning at the target cylinder and restarts the original processing. If the
error is not recovered from, retry processing (rezero seek and repositioning) is
performed up to the number of times specified in "Number of Retries during Seek
Error" in the MODE SELECT parameters.
5-24
C141-C009
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