Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: A neat INIT needed
Message-ID: <10044@hoptoad.uucp>
Date: 4 Feb 90 22:44:46 GMT
References: <1651@majestix.liu.se>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Organization: Eclectic Software, San Francisco
Lines: 47

In article <1651@majestix.liu.se> andwi@majestix.liu.se (Andreas Wickberg)
writes:
>Do you develop programs on a Mac ci? Will people try to run your
>programs on a SE or a Plus? How will it work?

Probably very slowly....

>Wouldn't it be neat to have an init called "SE" that makes your
>MacSuper respond like a slow SE? Imagine a 'Clock Frequency' control,
>where you set the speed between 0 and 100% of full speed.

It can't be done, I don't think.  However, you could easily create an
artificial slowdown at vertical retrace time.  This might be worth
doing.  You can really tell when a developer has used fast machines
exclusively for development when you run their programs on a slow
machine (e.g., FullWrite).

>And of course, it could also reduce your 19" color screen to a 9" B/W
>so you could see how dialogs and stuff will fit.

Good idea -- sort of a "Stepping In".  

>Perhaps it could also
>emulate different ROM-versions, although that's probably difficult
>without violating Apple's copyright.

No, I don't think this is possible.  And it points to the main problem
with the idea (though even a limited version might be worthwhile).
Most problems running 68020 or 68030 software on the 68000 machines are
alignment problems that just can't be flagged on the better processors
(unless you run in trace mode, which is probably even more slowdown
that you want!)  The second biggest problem is different ROM versions,
which I don't think you could simulate even with a PMMU; software
already installed at the time of the switch would be counting on the
ROM version.  So, it might be worthwhile to add a slowdown and
screen-shrinker INIT, but you're still going to have to do extensive
testing on the SE and Plus.  Given that, you might as well not bother
with the INIT; it doesn't save you much trouble.

>Any volunteers?

Heh heh -- what a kidder....
-- 
Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com

"The time is gone, the song is over.
 Thought I'd something more to say." - Roger Waters, Time