Degraded Mode; Degraded Mode Handling - IBM DDRS-39130 - Ultrastar 9.1 GB Hard Drive Specifications

10.1.9 Degraded Mode

There are certain errors or conditions which may impair the file's ability to function normally. Rather than
fail hard, the file is designed to be as responsive as possible. Also, in most cases, some action on the part of
the initiator may be used to restore normal operation. This mode of limited operation is called Degraded
Mode.

10.1.10 Degraded mode handling

If any degraded mode condition occurs an initiator will receive a sense key of Hardware error (4h) in the
next sense data requested. After clearing the sense key, the drive accepts commands according to the status
of the degraded mode.
The following table shows the degraded mode status with acceptable commands and aditional sense codes.
If a degraded mode exists, the Hardware error condition caused by the degrade mode will be recreated after
every POR, SCSI Reset or Bus Device Reset message. The following list shows the various operation
modes.
10.1.10.1 Degraded Mode Entry Condition/Consequence State
Degraded Entry Reason
Mode
Power on
Self Test Failure of a
fail start-up
sequence
Spin-up Can not start up
motor
Accepting Description and sense code
Request
The integrity of the drive is questionable.
Request Sense code =
Sense 4080 (diagnostic fail )
Inquiry
Start/Stop
unit
Write
Buffer(except
download
and save)
Return Spin-up Degraded Mode.
Request Sense code = 0400
Sense
Inquiry
Start/Stop
unit
Write
Buffer(except
download
and save)
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