🚀 go-pugleaf

In article <1992Nov18.154806.25061@r-node.gts.org> taob@r-node.gts.org (Brian Tao) writes:
> In article <bazyar.722074445@teal> bazyar@teal.csn.org (Jawaid Bazyar) writes:
> >
> >  GNO can _shut down_, and then run a P8, and return to GNO, but GNO can't
> >simply pause processes and run P8 because programs like Proterm and
> >AppleWorks 3.0 assume they have free run of memory; they'll overwrite
> >anything in GS memory whether they really use it or not.
> 
>     Not quite... Proterm and Appleworks at least are smart enough not to
> march all over things like PIF's and desk accessories and other memory
> already taken by GS/OS.

That is the least of the problems.  As Jawaid mentioned, ProDOS-8 and
GS/OS reside in the same areas of RAM (language card in bank 0).

GS/OS also uses a large chunk at the top of bank 0, the top of bank 1,
and all the language card space in bank 1.

There may be interrupt handlers within GS/OS device drivers sitting
there waiting to do GS/OS system service calls (the entry points to
which are in the bank 1 language card space) and all sorts of other
nasty things.  It isn't as simple as "copying GS/OS out and copying
ProDOS-8 in".

There might be a very slim chance that P8 would work if interrupts
were locked out the whole time, but that would prevent you from using
ProTERM.
-- 
David Empson

Internet: David.Empson@bbs.actrix.gen.nz    EMPSON_D@kosmos.wcc.govt.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand