[sebhc] hard sector substitute

Steve Thatcher melamy at earthlink.net
Wed Jun 30 07:14:15 CDT 2004

Hi Dave, I was not contemplating modification of the drives and I also wanted to make the device work on any hard sector system. N* uses HS and not HM for example (I have both N* and H88 systems...).

best regards, Steve Thatcher

-----Original Message-----
From: Dave Dunfield <dave04a at dunfield.com>


I guess I was not clear - I think it would be best to modify the drive so
that these signals are available to our adapter even when the drive is
deselected. If you use the traditional "Motor ON" control line instead of
the "Motor on select", you can keep the drive running even when it's not
selected - by attaching to the index sensor BEFORE the drive select logic,
we should be able to read it even if the drive is deselected.

As for the index output - you would have to gate that externally with select
anyway because we have to generate pulses that the drive does not generate,
Again if you were modifying the drive, you could do this by injecting the
additional sector pulses BEFORE the drive select logic.

dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Vintage computing equipment collector.

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