Re: How many K does a ProDOS Apple IIe of IIc floppy hold?

[dempson@actrix.gen.nz (David Empson)]

<slick_RCBD@hotmail.com> wrote:

> Stainless Steel Rat wrote:
> >
> > -----BEGIN PGP SIGNED MESSAGE-----
> >
> > Nathan Mates writes:
> >
> > >    Maximal capacity is 140K (35 tracks * 4K/track).
> >
> > There are several instances of a hack that will push that up to 160K.
> > Early 5.25" disk mechanisms (Shugart?) could not reliably handle more than
> > 35 tracks.  But the next generation, starting with the second or third
> > manufacturing run of the Disk ][ drives (IIRC) could handle 40.

Are you sure about that, and does it apply to later drives?  My Apple
5.25 Drive does NOT support 40 tracks.  It seems to be able to access 38
reliably, but the 39th one is dubious and the 40th is unavailable.

> > ProDOS can handle much larger volumes, but I do not know of any similar
> > hacks for it.

It is possible to patch the 5.25" driver to increase the maximum number
of blocks per disk, but I've never looked into the details.

One problem with any such patch (to either DOS 3.3 or ProDOS) is that
many utility programs are likely to have trouble dealing with the
nonstandard capacity, and you are forced to use a patched operating
system to access the disk at all.  (Careful labelling is advisable.)

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand