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The Unlicense
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Continuous head calibration test fails on high density discs #57

Closed darrenfreeman closed 2 years ago

darrenfreeman commented 2 years ago

ATK v1.18 on A4000 with Chinon FZ-357A.

Under floppy tests, the ID is found as "AAAAAAAA (DS-HD 80)" when a HD disc is in the drive. Signal test all looks good, read test looks good, write test looks good. The drive appears completely working.

However the head calibration test fails in a way that strongly indicates a bug in ATK. With every revolution of the spindle, the number of found sectors increases, until it shows 11/11 okay, then missing sectors shift in from the left, until no good sectors are found. The pattern repeats over and over, with the found sectors shifting to the right.

Since it should be showing 22 sectors, not 11, I think this is clearly just wrong. I would guess that only half of the buffer is being inspected for sectors, and the shifting pattern is caused by a changing delay in where the read data begins within the buffer.

I have reproduced the issue under fs-uae. I will be happy to test the fix on real hardware.

keirf commented 2 years ago

The calibration test is only designed for DD disks. Is there a reason to need to calibrate an HD disk?

darrenfreeman commented 2 years ago

I'm not sure, I haven't pulled mine apart yet. But it's safe to assume that people will try out all the tests, so if the test itself is failing, rather than the hardware, then it really needs to be disabled.