On 2013-05-30, at 00:51, Pete Rittwage wrote: > Certainly you "could" do it. I figured by the name of the extension and > the intro to the document, that it was always just designed as an > alternate/extension to the D64 format. Calling it "G64" when used for > 1571 or certainly Apple images makes less sense. You could use the same > format, though, just with a different signature. GCR-1571, GCR-APL2, or > whatever. Yes, signature would be quite important in such case. While the type could possibly be derived from the number of tracks, giving a clear hint wouldn't hurt of course. > On the Apple disk drive, they basically ripped out the Shugart board and > made a simple circuit controlled by software, so you have direct software > control over the actual field coils which move the heads. While their > "official" DOS only uses 35 tracks (0-34) like CBM, it is possible to > manipulate the heads to move not only 1/2 way in between tracks, but also > 1/4. It is still a wide head like the 1541, though, so it will destroy > data for 1.5 tracks when you write. Still interesting.. in CBM drives we can access half-tracks because the stepper is an 80 tracks one and the DOS moves it in double-steps. To move it in quarter-tracks would require different stepper I believe. Apart from this, if they need a special circuit to move it in quarter-tracks - does it make any sense when the non-modified drive can't access those anyway? -- SD! Message was sent through the cbm-hackers mailing listReceived on 2013-05-30 17:00:05
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