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Re: Working, slowly, on a BASIC.SYSTEM clone of sorts
Lyrical Nanoha wrote:
I've thought of trying to cruft together a BASIC.SYSTEM replacement, but
I'm not very familiar with any of what I'm doing. Oh well. Well,
here's what I'm trying to do.
1. Interface more like DOS 3.3, with chr$(4) recognized even in direct
mode and ASM programs, and MAXFILES working like DOS 3.3. Attempt to
limit code size to comparable with DOS 3.3 (since most of the OS is
above $D000 anyway). This should make DOS 3.3 programs more compatible
with it.
Do you have any examples of programs that run under DOS 3.3 that don't
run under ProDOS because ProDOS has more "lower 48" memory available?
I would expect that there are more that wouldn't run because they want
to use the "language card" memory (which ProDOS occupies).
Just ignoring MAXFILES should work fine, since ProDOS allocates file
buffers dynamically. Any DOS program that relies on static buffer
allocation will almost certainly have other OS dependencies that will
conflict with ProDOS.
Recognizing CHR$(4) in direct mode seems redundant, since most DOS or
ProDOS commands can already be typed in direct mode.
There would also be the need to support PEEKs for file length and load
addresses which are different for ProDOS than for DOS.
2. Commands BYE, CREATE, PREFIX like BASIC.SYSTEM (replacing INIT, INT
and MON). Also, line and filetype semantics implemented in BASIC.SYSTEM
may also need to be implemented here. Also, add - command. CATALOG is
CAT in BASIC.SYSTEM.
I guess I'm losing track of the objective. Why would any extensions to
the DOS command set make an environment more compatible with DOS 3.3?
I figure this might make some DOS 3.3 stuff easier to run on ProDOS as
PDOS.SYSTEM did RDOS.
So, would this be a kind of "hybrid" ProDOS with support for some DOS-
specific commands, or am I misunderstanding?
-michael
Music synthesis for 8-bit Apple II's!
Home page: http://members.aol.com/MJMahon/
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