Re: From the WTF File: ProDOS and DOS 3.3 peacefully cohabiting

[lyricalnanoha <lyricalnanoha@usotsuki.hoshinet.org>]

On Sat, 10 Jan 2009, David Wilson wrote:

> On Jan 10, 9:58Â pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
> > lyricalnanoha wrote:
> > > This contains a program I wrote to cram DOS 3.3 into 256 fewer bytes (by
> > > disabling format and revectoring a couple patches) so that ProDOS need
> > > not be overwritten. Â It's a SYS file, and runs from ProDOS 8. Â (I also
> > > tested it under GS/OS 5.0.4) Â On the DOS 3.3 side of the disk is a file
> > > RETURN TO PRODOS, which pokes in the MLI call for "quit", then executes
> > > it - proving that ProDOS is still fully available.
> >
> > DOS 3.3 will run happily in just 16KB...
>
> I was thinking that DOS and ProDOS did not overlap (P8 in language
> card, DOS in 3rd quarter of RAM) but then I realized why lyricalnanoha
> needed to do this - the ProDOS global page at BFxx would be
> overwritten by a 48KB DOS (and who would want to run a 16 or 32KB DOS
> on a machine with 48+KB?).
>
> Well done lyricalnanoha. I will have to try it out sometime.

That's exactly it.  I just crammed the stuff that would load into the 
ProDOS global page down into the BEAF-BEFF area, overwriting the format 
code.

I did a further tweak later that uses the image from dos.system *before* 
the jmp $9d84, instead of *after* as the first version, I want to primp it 
up a bit before I release that as the second edition, mainly I want to be 
able to format from both sides (for ProDOS I got HyperFormat).

Naturally I used Hybrid Create :P

-uso.