From: mpradhan@medicine.adelaide.edu.au (Malcolm Pradhan)
Newsgroups: comp.sys.mac.misc
Subject: MMInit again (was Re: TuneUp 1.1 companions??)
Date: 9 Apr 92 04:11:13 GMT
Organization: Faculty of Medicine, University of Adelaide

In article <8APR199215211122@nssdca.gsfc.nasa.gov> kayser@nssdca.gsfc.nasa.gov
(Susan E. Kayser NSSDC/STX (301)513-1673) writes:
>&MMInit was written to correct a bug in memory management in the Mac IIci.  
>It's no use to you on a IIfx.  I suspect that it's still useful to IIci users,

>even with tune-up, since the problem was specific to one set of ROMs, but if
>anyone knows for sure, please respond! 

 MMInit could almost qualify as a virus! :-)

 Here are some responses about MMInit that I received last year when enquiring
about the init, Australian MacWorld had recommded it's use despite Apple's
advice not to use it.

 Regards,
 Malcolm
_________________________________________________________________
    Malcolm Pradhan
    Medical Computing, Faculty of Medicine         _--_|\
    University of Adelaide, South Australia       /      \
    InterNet: mpradhan@medicine.adelaide.edu.au   \_.--x_/
    Fax: +618 223 2076  :x marks the spot:              v


--------------------- cut hither ----------------------------

From:	SMTP*"INTL.DTS@applelink.apple.com" 16-JUL-1991 04:59:48.56
To:	mpradhan@f.adelaide.edu.au
CC:	
Subj:	Re: MMInit proof needed for Aus. MacWorld

Date: Mon, 15 Jul 91 12:30:00 -0700
Message-Id: <9107151930.AA08810@internal.apple.com>
From: INTL.DTS@applelink.apple.com (Tim Dierks)
To: mpradhan@f.adelaide.edu.au
Subject: Re: MMInit proof needed for Aus. MacWorld
Organization: UK Mac DTS, SRL Data, London

In article <1991Jul15.092505>, mpradhan@f.adelaide.edu.au writes:
> Does anyone have a copy of the mail messages from Keith
> Rollin et.al about MMInit, or know where I could get a copy from to forward

Here's the standard spiel from MacDTS...

-------
We received your inquiry on the ROM bug in the Macintosh IIci, IIfx, IIsi, and
LC Memory Manager under System 6.0.x and the unofficial MMInit which was
circulating temporarily to address this problem.

Under System 6.0.x, Apple had identified a minor problem with the Memory
Manager in the Macintosh IIfx, IIci, IIsi and LC. This problem resulted in
a performance degradation in an extremely small number of applications and
did not cause system crashes. We believe this was an insignificant problem
that affected few applications and very few customers. The problem was not
new and was not caused by the introduction of System Software 6.0.5 or 6.0.7.

Based on developer feedback, customer feedback, and extensive in-house
testing, Apple has identified very few affected applications. Because the
problem only affects an extremely small number of developers, Apple is
working with those developers to fix their applications.  The best solution,
however, is to upgrade to System 7.0, as it includes an enhancement to the
Memory Manager to address this issue.

During extensive testing and research, Apple investigated a variety of
solutions to enhance the Memory Manager performance. One area researched was
a software solution called the Memory Manager INIT (a software 'patch'), or
MMInit as it's most often called. Through testing we discovered that this
patch did not enhance Memory Manager performance and introduced risks such
as decreased performance in some mainstream applications.

An unofficial version of the Memory Manager INIT has surfaced. This INIT
should not be used, because it has been modified from Apple's experimental
version and could cause data corruption, data loss, and crashes. Apple
strongly urges that you discard the INIT if you have obtained a copy, and
not use it.  If any version of this INIT is used under System 7.0, it
defeats the enhanced Memory Manager and reintroduces the bugs which where
present in the System 6.0.x Memory Manager.

You may still wonder if you have been affected by this and how to avoid it
under 6.0.x. The problem is most severe when allocating pointers in a heap
with a rather large number of handles (on the order of tens of thousands).
ItUs helpful to allocate enough master pointers (via MoreMasters) during
initialization. If the Memory Manager has to call MoreMasters later on, not
only could it fragment memory, but it could take an exceedingly long time.
It's also helpful not to allocate thousands of handles. Besides requiring
lots of master pointers, it takes the Memory Manager a long time to crunch
through them during heap compaction.

Chances are you're not being plagued by this rare 'bug.' Before you go crazy
wondering if the 'bug' exists in your computer, read and check the following
list of factors affecting CPU performance:

  *  Monitor size, bit depth, color or black and white
  *  On-board video versus video card
  *  Hard disk size, fragmentation, interleaving (which CPU
     the hard disk was initialized on, and which CPU is now using it)
  *  AppleTalk active
  *  Servers mounted
  *  Electronic mail installed
  *  Public Folders (shared folders)
  *  INITs installed
  *  Fragmented heap (other applications could fragment/corrupt
     the system heap)
  *  Amount (and speed) of RAM
  *  Mixing speeds of RAM (causes random crashes)
  *  Finder vs. MultiFinder
  *  Disk cache
  *  Cache cards installed
  *  Floppy disk access
  *  Peripherals connected (such as CD-ROM and tape drives)
  *  Background printing

If you're indeed experiencing a performance problem, make sure that the above
conditions are not contributing to it.
--------------------------------------------------------------------

From: keith@Apple.COM (Keith Rollin)
Newsgroups: comp.sys.mac.programmer
Subject: Re: MM Init
Date: 17 Mar 91 00:07:10 GMT
<1991Mar11.173337.1044@ni.umd.edu> <565@genco.bungi.com>
Organization: Apple Computer Inc., Cupertino, CA

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.

---------------

Keith Rollin  ---  Apple Computer, Inc. 
INTERNET: keith@apple.com
    UUCP: {decwrl, hoptoad, nsc, sun, amdahl}!apple!keith

--------------------------------------------------------------------

From: REEKES@applelink.apple.com (Jim Reekes)
Newsgroups: comp.sys.mac.system
Subject: Re: MMInit in System 7.0?
Date: 28 May 91 23:51:03 GMT
Organization: Apple Computer, Inc.

In article <53397@apple.Apple.COM>, blob@Apple.COM (Brian Bechtel) writes:
> 
> hamalai2@rapola.cc.tut.fi (H[M[L[INEN TIMO) writes:
> >Do I still need Memory Manager Init or is it in System 7?
> 
> The performance problem that Memory Manager Init fixes is fixed in
> System 7.  You do not need that INIT.
> 
> --Brian Bechtel     blob@apple.com     "My opinion, not Apple's"

More than that, no one should be using that init on any system running
any version of the System.  It has bugs that causes some crashes which
was a problem while we were testing System 7.  If you do have this init, you
should remove it and don't pass it around.  It does little if anything
for you, and the risk is too great.  It is NOT an Apple recommend fix for
any bugs.

Jim Reekes E.O., Macintosh Toolbox Engineering
-- 

--------------------------------------------------------------------

From: keith@Apple.COM (Keith Rollin)
Newsgroups: comp.sys.mac.system
Subject: Re: MMInit in System 7.0?
Date: 28 May 91 07:44:22 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <1991May27.213557.20337@cc.tut.fi> hamalai2@rapola.cc.tut.fi writes:
>
>Do I still need Memory Manager Init or is it in System 7?
>

You definitely do _not_ want the MMInit under 7.0. First of all, yes,
it is built in (has been since 7.0b3). Secondly, since the INIT was
essentially a copy of the Memory Manager in RAM form, it dutifully
replicates all the bugs in the Memory Manager. Well...not that there
are a lot; only a couple. But there is one in 32-bit mode that will
corrupt memory. This is fixed in 7.0, but if you use MMInit, it's
possible that you'll reintroduce the bug.

-- 
--------------------------------------------------------------------

Keith Rollin  ---  Apple Computer, Inc. 
INTERNET: keith@apple.com
    UUCP: {decwrl, hoptoad, nsc, sun, amdahl}!apple!keith
"But where the senses fail us, reason must step in."  - Galileo