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

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

mmphosis <markstock@mail.com> wrote:

> I suspect that calling the File Manager routines might be a bit tricky
> and might have a bug or two.  Perhaps, this code has a bug or two as
> well.  Seems that it might be doing an extra call to RWTS to write some
> data to track 0 sector 0.  Perhaps, some initialization or termination
> routine needs to be called before calling the File Manager routine.
> 
> In the past, I used the RWTS routines directly.  I think I checked for
> the carry flag being set which indicated an error.  The error code is
> returned in the parameter list for RWTS.  The error code might also be
> stored in location $48 in the zero page which conflicts with other
> routines that might use this location -- a cause of some bugs.

I tried using the DOS 3.3 File Manager briefly and it required a fair
amount of hacking to use it at all. My only reference material would
have been Beneath Apple DOS. I remember at least one bug, something to
do with counts associated with write operations having an off-by-one
error?

RWTS was easy enough, but using the BASIC command interface from machine
code also had its problems.

Hm, I wonder why I dropped DOS 3.3 like a hot potato as soon as ProDOS
was available.

Something to do with the properly documented and well implemented
machine language interface?

Nah, that has to be a coincidence. :-)

-- 
David Empson
dempson@actrix.gen.nz