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Re: Hardware musings

Ed Eastman wrote:

Michael J. Mahon wrote:


Yes, if it is possible to seek to half- and quarter-track positions on
a PC drive.
If using a HD 5.25" drive, you can get all the track data. As noted before, the quarter track data is going to bleed 100% into the 1/2 tracks. There should be no need to read a quarter track as it will be the same as a half track read, even on a spiral disk or 'wide track'. 

I agree that if the data was written with a standard-width head, that
1/2 tracks should be sufficient, since the HD head is about 3/8-Apple-
tracks wide.

This approach may still leave some uncertainty about exactly how to
position the head of an Apple drive to re-create the disk using an
Apple drive.

(And in order to use an HD drive's narrow head to write a disk for an
Apple drive it would be necessary first to degauss the disk.)


BTW, any index hole scheme will have problems with "flippy" disks.
That would require either another hole in the disk jacket or another
index hole sensor on the drive.
I've never seen a synch check on the back of a diskette. That's all I'd want it for was to verify the synch of the track. There should be no problem as the catweasel should allow you read the back anyway, even without the index pulse. 

I haven't seen this either, but it is quite conceivable that it would
have been used.

In any case, it would be possible to recover the sync without the index
pulse (though the PC controller may leave more timing uncertainty
between seeking and reading than the Apple scheme does).
I may have to invest in one of those. But I wouldn't even know where to begin programming the thing. 

Yes, when I looked at the Catweasel a few years ago, I noted the
conspicuous absence of PC software to process Apple disks, and
I was not excited by the prospect of programming the PC to do so.

-michael

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