Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!amdcad!ames!nrl-cmf!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.sys.apple
Subject: SoftSwitch
Message-ID: <7231@brl-smoke.ARPA>
Date: 9 Feb 88 16:06:10 GMT
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 59
Keywords: Apple IIGS task switcher

Some of you may already know about this product.  However, I think it
deserves a plug, so here goes:

I was getting really frustrated playing Return of Werdna, because of
extremely unfavorable rolls of the dice at critical times forcing me
to keep starting over.  So, recalling something about SoftSwitch from
Roger Wagner Publishing, I bought a copy, and guess what -- now I can
instantly snapshot the state of the game at a couple of key positions
and instantly switch back to one of the snapshotted states when things
go badly in the game.  In fact, it is so convenient that it is worth
while to keep rolling dice from the same saved state until getting a
favorable outcome, then replace the saved state with the new one, etc.
Ths is the only way I know of to map every corner of the minefield on
level 8 with a level-3 Werdna, for example (forcing +8 HP per DIOS
potion).

Here's what SoftSwitch does, in essence:
It works only on a IIGS and is installed as a Classic Desk Accessory.
At any point in an 8-bit application (other than while a disk is being
accessed), press open-apple/ctrl/esc to get to the console/CDA menu,
and invoke SoftSwitch.  It shows mini-screens of the interrupted
application and up to three snapshotted states.  By a couple of
keystrokes, one can clear a snapshot, copy the interrupted state into
a snapshot, or copy a snapshot into the interrupted state (this is
the "switch").  Upon leaving SoftSwitch, then leaving the console/CDA
menu, one is back at the interrupted application, which MAY BE A COPY
OF A PREVIOUSLY SAVED STATE.  The snapshots are saved in allocated
memory (at least 512KB expansion recommended), and there is a utility
called "KeepSake" that can be run to save snapshots in disk files or
load snapshots from disk files.  (Great for games without a convenient
"save game" feature!)

The main reason this technique can work is that there is really no
disk write caching in DOS 3.3 or PRODOS-8, so there is no need to flush
internal buffers to the disk before switching to another task.

SoftSwitch works best if one of the snapshots is of the DeskTop (NOT
the Finder, which works in 16-bit mode; the DeskTop runs in 8-bit mode).
The DeskTop is supplied with SoftSwitch, in case you don't have it (i.e.
you have only the latest IIGS System Disk).  This makes it possible to
at any point in an 8-bit application quickly switch to the DeskTop to
create directories (oops, "folders"), format disks, etc. then switch
back to the application right where you left it.  It should be obvious
how handy this can be..

The main limitation is that 16-bit applications cannot be switched,
for a variety of techincal and practical reasons.  Also, some 8-bit
applications may disable interrupts so that you can't get to the
control panel (console/CDA menu) to invoke SoftSwitch.  But when it
does work, it is great!  It seems very well designed, too; it beeps
and asks for confirmation if you attempt to do something that would
irretrievably lose the interrupted state, but it just goes ahead and
does what you request (typically using a single obvious keystroke)
in all other cases.

I admit to being somewhat dubious when I read about this product in
Open-Apple, but now that I've used it I can attest that it really
works as advertised.  It's useful for a lot of applications, but
I especially think no IIGS Wizardry player should be without it!