Re: DOS 3.3 File Manager calls - stomping on Track 0, sector 0

["Michael J. Mahon" <mjmahon@aol.com>]

schmidtd wrote:
> Michael J. Mahon wrote:
>
> > josephoswaldgg@hotmail.com wrote:
> >
> > > Don't know what trap this might be, but that byte pattern looks
> > > something vaguely like the volume free-sector map. Is your disk's VTOC
> > > valid?
> >
> > That was my guess, too--that the updated VTOC is mistakenly being
> > written back to Tk 0, Sec 0.
>
>
> The VTOC seems to be intact - I can catalog, read, write, and delete
> files just fine after the damage occurs.

Another likely possibility is that a random piece of uninitialized
memory is being written to "0/0"--I've often seen 00 00 FF FF as
the "power up" pattern in RAM.

> > > Really, the Ctrl-D "BSAVE" solution isn't *that* bad is it?
>
>
> When looking up posts on the subject, I came across one that accused
> the Ctrl-D method of being a "hack" and called the poster's manhood
> into question, or some such thing.  I figured I'd give FM a try.

Sticks and stones...  ;-)

Seriously, DOS never had a supported FM interface, and the
BASIC interface is quite straightforward and functional.

> > Exactly.  Is this just an exercise in seeing if it can be done,
> > or would you rather save time and get the job done reliably (even
> > with patched versions of DOS)?
>
>
> Both, kinda.  I've since figured out why Ctrl-D wasn't working for me
> in the first place: a call to $fe93 (SETVID), intended to revert to
> 40-column output from 80, causes it to fail.

Ah--so now the coast is clear.  ;-)

-michael

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