Re: Disk ][ Launcher (was: Late night musings...)

[nparker@cie-2.uoregon.edu (Neil Parker)]

In article <Pine.SGI.3.91r.960829090359.18978A-100000@freenet> "Greg J.
Buchner" <buchner@freenet.msp.mn.us> writes:
>[...]
>Well, I had Swatdisk for a while, but I couldn't find any current
>need for it for me.  I don't need to get anything off of 5.25 images,
>I just want to run stuff off of them, mostly Ultima ///, Ultima V &
>Wings of Fury.  I'm not looking for a desktop //e emulator...what
>I'd be interested in is something like DOS 3.3 Launcher that instead
>of re-routing the DOS 3.3 stuff to ProDOS commands, would route the
>5.25 disk interface calls to ProDOS.

The problem with that is that there aren't any 5.25 disk interface calls to
intercept (well...there are a couple of entry points used early in the disk
boot process, but almost nobody uses those for anything except the early
stages of disk booting).  For all practical purposes, the next lower level
of access below RWTS is direct access to the disk drive hardware.

Programs that access the disk drive through means other than a standard RWTS
call generally do so by accessing the disk drive hardware control registers
directly.  The only reasonable way to make such a program work under a
DOS-3.3-Launcher-like scheme would be to modify the program by ripping out
its custom disk access code, and replacing it with something that calls
the DOS 3.3 Launcher routines.

I suppose one could, in theory, write a 6502 emulator that recognized and
rerouted access to the disk drive hardware, but you probably wouldn't want
to use the resulting product (can you say "S...L...O...W"?).


The path of least resistance for running those old programs is probably to
spend a few bucks on a 5.25-inch disk drive and interface card.  They're
cheap nowdays--look in comp.sys.apple2.marketplace, or go to your local
thrift stores.  (My local Goodwill often has that kind of thing for sale
for around $10 or so, and my experience is that it's usually in pretty good
shape--people donate old computer equipment because some salesman convinced
them it's obsolete, not because it's broken.)

              - Neil Parker
-- 
Neil Parker, nparker@{cie-2,cie}.uoregon.edu, http://cie-2.uoregon.edu/~nparker

                     "Bad move, Neil!"  -- The Tick