Execution Timing Of Self-Calibration; Command Processing During Self-Calibration - Fujitsu MHT2080AH - 80GB 5400 RPM PATA Hard Drive Product Manual

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:
When it passes from the power on for ten seconds and the disk drive shifts to
Active Idle mode.
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 10 seconds.
If the error rate recovers to a value exceeding the specified value, self-calibration
is not performed.
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