Fujitsu MHW2040AT - Mobile 40 GB Hard Drive, Product Manual

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Theory of Device Operation
4.5.2 Execution timing of self-calibration
Self-calibration is performed once when power is turned on. After that, the disk
drive does not perform self-calibration until it detects an error.
That is, self-calibration is performed each time one of the following events occur:
•
In the case that the disk drive starts up normally, the first part of self-
calibration starts after a lapse of 100 msec. The execution of first part is about
150 msec. length. The remains is executed thereafter the transfer to Active-
Idle state which takes about 200 msec.
The latter is interrupted when the disk drive receives a Host command, and it
resumes after next transfer to Active-Idle state.
•
The number of retries to write or seek data reaches the specified value.
•
The error rate of data reading, writing, or seeking becomes lower than the
specified value.
4.5.3 Command processing during self-calibration
This enables the host to execute the command without waiting for a long time,
even when the disk drive is performing self-calibration. The command execution
wait time is about maximum 72 ms.
When the error rate of data reading, writing, or seeking becomes lower than the
specified value, self-calibration is performed to maintain disk drive stability.
If the disk drive receives a command execution request from the host while
performing self-calibration, it stops the self-calibration and starts to execute the
command. In other words, if a disk read or write service is necessary, the disk
drive positions the head to the track requested by the host, reads or writes data, and
then restarts calibration after about 3 seconds.
If the error rate recovers to a value exceeding the specified value, self-calibration
is not performed.
4-8 C141-E250