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From: lsr@Apple.com (Larry Rosenstein)
Newsgroups: comp.sys.mac.misc,comp.sys.mac.system
Subject: Re: Is there a memory management bug in the fx,ci, and si ROM ?
Message-ID: <11678@goofy.Apple.COM>
Date: 9 Jan 91 18:26:56 GMT
References: <127472@linus.mitre.org>
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 26

In article <127472@linus.mitre.org>, dsb@mbunix.mitre.org (Blodgett) writes:
> 
> 
> 	Question: I have heard that there is a bug in the Mac ROMs in the
> 	fx, ci, and possibly the si. I was told that this bug is called a 
> 	redundant memory error. Normally the mac moves data 32 bits at a time,
> 	but when the computer is pushed to its upper limits of memory that
> 	it only moves 2 bits at a time.

The description of the bug is totally wrong (and doesn't even make much
sense).  The actual bug involves moving memory blocks around when trying
to make room for a non-relocatable block.  The bug is that a hint telling
the Memory Manager where to start scanning the heap is wrong, and the
Memory Manager ends up scanning the entire heap unnecessarily.

The bug is only supposed to affect applications that allocate a lot of
non-relocatable blocks, which means it doesn't show up in the majority of
applications.

> 
> 	Has anyone else heard about this ? If so is there a work around, or
> 	a bug fix planned?

There is a fix being worked on.

Larry Rosenstein