Fujitsu 80, Scsi Logical Interface Specifications

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1.7 Command Processing Exceptions
C141-C010 1-27
Table 1.4 Outline of SCSI Bus Error Recovery Processing
Item Type of Error Error Recovery Processing
1 MESSAGE OUT phase parity error Retry the erroneous phase up to 3
times max / "CHECK CONDTION"
Status
2 COMMAND phase parity error Retry the erroneous phase up to 3
times max / "CHECK CONDTION"
Status
3 DATA OUT phase parity error "CHECK CONDTION" Status
4 Received INITIATOR DETECTED ERROR message. Retry the erroneous phase up to 3
times max / "CHECK CONDTION"
Status
5 Received MESSAGE PARITY ERROR message. Re-execute RESELECTION phase
6 RESELECTION phase time-out
(2)
Recovery procedures for disk drive errors
The IDD executes error recovery listed in Table 1.5 for an error detected during access to data on the
disk. Note that the recovery increases command processing time because of rotation delay for
repositioning to the data block on the disk or initialization of the positioning control system.
The INIT can use the MODE SELECT parameter Page 1 (read/write error recovery parameter), Page 7
(verify error recovery parameter), and Page 21 (additional error recovery parameter) to control the retry
count. However, use the default value specified by the IDD in general operation.
Table 1.5 Outline of disk drive error recovery processing
Item Type of Error Error Recovery Processing
1 Seek Error Rezero (Return to Zero Cylinder), readjustment of positioning
control system, and repositioning to the data block.
2 Uncorrectable Data Error Reread
3 Correctable Data Error Correct by ECC.
Note:
The execution start timing of this automatic readjustment operation generally cannot be
predicted by the INIT. The automatic readjustment operation is performed when there are no
commands being executed or in the queue, but execution of commands issued immediately after
the IDD starts the readjustment operation, are forced to wait until the readjustment operation is
completed.