Fujitsu MHT2080AH - 80GB 5400 RPM PATA Hard Drive Product Manual page 236

Operations
(3) Status report in the event of an error
The status report concerning an error occurring during writing onto media is
created when the next command is issued. Where the command reporting the
error status is not executed, only the error status is reported. Only the status of an
error that occurs during write processing is reported.
<Exceptions>
The error status is not reported in the following case:
The reset command is received after an error has occurred during writing to
media.
Reset processing is performed as usual. The error status that has occurred
during writing to media is not reported.
(4) Enabling and disabling
Enabling and disabling of the Write Cache function can be set only with the SET
FEATURES command. The setting does not changed even when the error status
is reported.
The initial setting is stored in the system area of media. System area information
is loaded whenever the power is turned on.
(5) Reset response
When a reset is received while cached data is stored on the data buffer, data of the
data buffer is written on the media, and reset processing is then performed. This
is true for both a hard reset and soft reset.
(6) Cashing function when power supply is turned on.
The cashing function is invalid until Calibration is done after the power supply is
turned on.(about 10 sec) It is effective in Default after that as long as the cashing
function is not invalidly set by the SET FEATURES command.
If Write Cache is enabled, there is a possibility that data transferred
from the host with the Write Cache enable command is not
completely written on disk media before the normal end interrupt is
issued.
If an unrecoverable error occurs while multiple commands that are
targets of write caching are received, the host has difficulty
determining which command caused the error. (An error report is
not issued to the host if automatic alternating processing for the
error is performed normally.) Therefore, the host cannot execute a
retry for the unrecoverable error while Write Cache is enabled. Be
very careful on this point when using this function.
If a write error occurs, an abort response is sent to all subsequent
commands.
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IMPORTANT
C141-E195-02EN