Fujitsu MAN3367 User Manual
C141-E124-01EN
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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.
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.
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.
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.
If the error cannot be recovered from even when retry processing is executed the specified number
of times, the IDD terminates the command which is currently being executed with a CHECK
CONDITION status. The sense key in the sense data at this time is "HARDWARE ERROR [=4]"
and the sense code indicates "Mechanical positioning error [=15-01]" or "Positioning error
detected by read of medium [=15-02]."
of times, the IDD terminates the command which is currently being executed with a CHECK
CONDITION status. The sense key in the sense data at this time is "HARDWARE ERROR [=4]"
and the sense code indicates "Mechanical positioning error [=15-01]" or "Positioning error
detected by read of medium [=15-02]."
(2)
Read error in uncorrectable data
This error is a failure to detect the Sync Byte pattern during reading of data or an ECC error for
which correction processing is impossible. If this error is detected, the IDD, after waiting one
revolution of the disk media, tries reading again. When the error is not recovered from, reading is
retried repeatedly the number of times specified in the MODE SELECT parameter ("Number of
Retries during Read" or "Number of Retries during Write").
which correction processing is impossible. If this error is detected, the IDD, after waiting one
revolution of the disk media, tries reading again. When the error is not recovered from, reading is
retried repeatedly the number of times specified in the MODE SELECT parameter ("Number of
Retries during Read" or "Number of Retries during Write").
In cases where correction is possible during execution of retry processing, the processing
procedure is according to "Correctable Data Read Error" in item (3). If errors cannot be recovered
from even after retry is executed the specified number of times, the IDD terminates the command
that is currently being executed with a CHECK CONDITION status. The sense key in the sense
data at this time is "MEDIUM ERROR [=3]" and the sense code indicates "Sync byte not found for
data field [=13-00]" or "Unrecovered read error [=11-01]."
procedure is according to "Correctable Data Read Error" in item (3). If errors cannot be recovered
from even after retry is executed the specified number of times, the IDD terminates the command
that is currently being executed with a CHECK CONDITION status. The sense key in the sense
data at this time is "MEDIUM ERROR [=3]" and the sense code indicates "Sync byte not found for
data field [=13-00]" or "Unrecovered read error [=11-01]."
In this error retry processing, rereading accompanied by head offset processing is performed.