On Sat, 10 Jan 2009, David Wilson wrote:
On Jan 10, 9:58� 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. � It's a SYS file, and runs from ProDOS 8. � (I
also
tested it under GS/OS 5.0.4) � 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.