Fujitsu DISK DRIVES MHL2300AT, Product Manual

Page: 222 / 232

6.6 Write Cache
C141-E104-03EN 6-23
The drive uses a cache data of the last write command as a read cache data. When
a read command is issued to the same address after the write command (cache
hit), the read operation to the disk medium is not performed.
If an error occurs during the write operation, the device retries the processing. If the
error cannot be recovered by retry, automatic alternate assignment is performed. For
details about automate alternate assignment, see item (3) of Section 6.4.2.
The write cache function is operated with the following command.
•
WRITE SECTOR(S)
•
WRITE MULTIPLE
•
WRITE DMA
IMPORTANT
When Write Cache is permitted, the writing of the data transferred
from the host by the above mentioned Write Cache permit
command into the disk medium may not be completed at the
moment a normal ending interrupt has occurred.
In case a non-recoverable error has occurred during receiving more
than one write command, it is difficult for the host to identify a
command that caused the error.
(However, the error is not reported to the hose if an error at writing
has been processed normally.)
Therefore, note that it is difficult for the host to retry an operation
that caused a non-recoverable error.