[Coco] floppy controller update
afra at aurigae.demon.co.uk
Sun Jul 6 18:32:01 EDT 2008
Chuck Youse wrote:
> On Sun, 2008-07-06 at 16:13 -0400, Chuck Youse wrote:
> The more I think about this, the more I think it must be an interleaving
> issue. Consider that the sectors are most likely laid out in order by
> Linux's fdformat. Consider that I appear to be getting something in the
> neighborhood of one sector every 200-250ms, and then consider that at
> 300RPMs, one revolution takes about 200ms. Bingo.
> Does that seem right? Is anyone even listening to my jabbering
> anymore? ;)
Yeah that seems reasonable, IIRC stock RS/Dragondos uses a 1:4
interleave, and most other DOSes of that vintage also seemed to use
interleaving other than 1:1, which is as you say prolly what Linux is
laying down when formatting, which is pretty much the reason that I
always format CoCo/Dragon disks in the actual machine and then write
them in Linux, because interleave is set when formatting, linux will
write it correctly, however it always formats with 1:1, dunno if there
is a way of over-riding this tho.
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !
"You can twist perceptions, but reality won't budge" -- Rush.
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