Re: Disk II Phase Question

["Jplcsch" <jplcsch@wanadoo.fr>]

Look the routine of  flight simulator II, it's really the maximum you can
put on a track (18 pages with a small amount for the translation table!)
on look the track with CIA or any other utility
to help you:
Syncro are $FE
start of track $D5 $AA $D5
after you found a transalation table
a close byte $94
the marker of every sector (just one) $D5
18 pages  (if you unassemble the read routine you'll found a loop with $12
to test the nb of sectors read on the track)
checksum
close markers for the track $DE $AA
good luck



"Eric Smith" <eric-no-spam-for-me@brouhaha.com> wrote in message
qhmzv9n2zb.fsf@ruckus.brouhaha.com">news:qhmzv9n2zb.fsf@ruckus.brouhaha.com...
> "Bryan Parkoff" <nospam@nospam.com> writes:
> >     I understand now.  The reason is that I say ($5F00) 24,320 bytes or
> > 194,560 bits per track.
>
> The number of nybbles per track varies because normal nybbles are
> 8 bits each, while self-sync nybbles are either 9 or 10 bits (determined
> by whether the FF pattern is written to the shift register every 36 or 40
> microseconds, instead of 32 microseconds for a normal nybble).
>
> There are nominally 50,000 bit positions on a track, which means that
> normally there would never be more than 6250 nybbles per track.  Given
> the variation in drive speeds, you might see up to 5% higher in practice.