Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!keith
From: keith@Apple.COM (Keith Rollin)
Newsgroups: comp.sys.mac.programmer
Subject: Re: MM Init
Message-ID: <50342@apple.Apple.COM>
Date: 17 Mar 91 00:07:10 GMT
References: <4017@uakari.primate.wisc.edu> <1991Mar11.173337.1044@ni.umd.edu> <565@genco.bungi.com>
Organization: Apple Computer Inc., Cupertino, CA
Lines: 64

In article <565@genco.bungi.com> rad@genco.bungi.com (Bob Daniel) writes:
>Has the IIci ROMs been updated in newer IIci's so that the MM Init is no
>longer needed?  If so, what version of ROM has the fix?  A friend of mine
>just got a new IIci and was wondering if he needs to use the init.

This is a copy of the letter I sent to Bob:

Bob,

IMHO, almost no one should need to be using MMInit. This is for several
reasons which I'll list below, but first let me answer your question.
No, the fix to the Memory Manager is not in any newer ROMs (Apple can't
just quickly slap out new ROMs every day, you know), but a patch to the
Memory Manager _is_ is System 7.0.

As for the reasons why you shouldn't need to run MMInit:

1) Almost no applications are affected by the bug. There is only one
   that we know about, ProGraph. If you are not running that, then it
   is 99.99% likely that running the INIT will have no affect on your
   IIci.

2) The INIT is a duplicate of the Memory Manager in the IIci ROM, with
   the bug fixed. This duplicate includes other bugs in the Memory
   Manager that occur only in 32-bit mode. These problems are fixed in
   System 7.0 (which is the only way you can run in 32-bit mode), but
   if you run the INIT, you'll re-introduce those bugs into your Mac.

3) Even the problem with ProGraph is easily fixed. For reasons which
   are too elaborate to go into here, unlocking the CODE resources will
   speed up ProGraph's execution. As I understand it, there are still
   some problems with the applications that ProGraph creates, but it's
   possible that those could be fixed, too, eliminating the need for
   MMInit.

4) The INIT has shown some compatibility problems with some major
   3rd party software. The symptoms of these problems include crashes
   into the debugger, mouse freezes, and the inability to boot your
   Macintosh.

5) Performance testing of the INIT gave inconclusive results as to its
   overall usefulness. Though speed deviances were mostly in the
   standard margin for error, there was some evidence that the INIT
   might actually be _slowing down_ some applications!

With the exception of ProGraph and another as yet unreleased program, I
know of no programs that have definitely shown that they run better
with the INIT than without. This includes some of the most memory
intensive applications I know, like MPW and 4th Dimension. Many people
THOUGHT that the INIT sped things up, but when those operations were
put under the stopwatch, it was found that those reports were invalid.

People have also reported that their machines have stopped crashing, or
don't crash as often, after they install the INIT. Well, that may be
true, but not because of anything the INIT does. The INIT does not fix
or address any crashing bugs in the Memory Manager -- and, as far as I
know, there aren't any such bugs.

-- 
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Keith Rollin  ---  Apple Computer, Inc. 
INTERNET: keith@apple.com
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"I don't work in DTS anymore, so don't expect what I say to be right."