Fujitsu MPG3xxxAT Product Manual page 198

At the time that the drive has stopped the command execution after the error recovery has failed,
the write cache function is disabled automatically. The releasing the disable state can be done by
the SET FEATURES command. When the power of the drive is turned on after the power is
turned off once, the status of the write cache function returns to the default state. The default state
is "write cache enable", and can be disable by the SET FEATURES command.
The write cache function is operated with the following command.
WRITE SECTOR(S)
WRITE MULTIPLE
WRITE DMA
When the write cache function is enabled, the transferred data from the
host by the WRITE SECTOR(S) is not completely written on the disk
medium at the time that the interrupt of command complete is
generated. When the unrecoverable error occurs during the write
operation, the command execution is stopped. Then, when the drive
receives the next command, it generates an interrupt of abnormal end.
However an interrupt of abnormal end is not generated when a write
automatic assignment succeeds. However, since the host may issue
several write commands before the drive generates an interrupt of
abnormal end, the host cannot recognize that the occurred error is for
which command generally. Therefore, it is very hard to retry the
unrecoverable write error for the host in the write cache operation
generally. So, take care to use the write cache function.
IMPORTANT
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