a "free" system exension by Brian Zuk which is installed by
theRAM Charger installer to fix a common problem that crashes
What is the problem?
Many popular Macintosh applications incorporate a
"canned" package of software, known as Mercutio MDEF,
that allows developers to easily and elegantly extend the
power of their application menus. It was discovered
applications that use pre-version 1.5 of this package were
crashing systems as a result of a bug in Mercutio
MDEF. Although this problem has surfaced because of a
bug in the Mercutio MDEF package, Apple reports that
there are other (non-Mercutio) applications, and even parts
of the OS, that can cause the crash.
Does this effect my system?
Yes. As far as we know, this effects all systems if you
happen to be running an application using pre -version 1.5
Mercutio MDEF, and other software may cause the
problem as well. Also, Apple currently claims that will not
put a fix in the system (see below). Since we do not know
the list of applications which are dangerous, we recommend
everyone run the patch which is basically painless.
What is the fix?
A number of "free" system extensions have been developed
by generous programmers that will fix the problem. Any one
of these added in your extensions folder will avoid the
problem. In specific, we have chosen
MercutioHUnlockPatch as the extension we prefer.
Since no drawbacks are known, the RAM Charger installer puts
MercutioHUnlockPatch in your system (if a more recent
version is not already installed).
Why might the RAM Charger installer warn me?
If you already have another known "Mercutio" fix
extension installed, then the RAM Charger installer will let
you know - since having multiple fixes is a waste. As far as
we know, there is no problem having multiple fixes
installed. However, that would be extra overhead. If you are
warned, you might wish to take the opportunity to disable
one of the fixes.
What does Apple have to say about this?
In the Apple
All users, including developers, should consider
installing a system extension which Apple will soon
release to address this problem. This extension will
protect you from symptoms which result from code which
you cannot fix until revised applications appear which do
not have the problem. You will be able to obtain this
extension, along with further details, from another web
page. We'll post a specific reference here as soon as it
becomes available. [as far as we know, none is availabe
from Apple yet, only from random generous developer
Apple does not currently plan to roll this
functionality into Mac OS. This is because the problem
warrants fixing for more than just the next version of
Mac OS. (The extension has been qualified under Mac OS
7.6 and later.) Another reason this fix will not be
rolled into the system is that it would require the
Memory Manager to have intimate knowledge of QuickDraw,
and minimizing this kind of coupling is in everyone's
long-term best interest. A future version of Mac OS will
include a work-around for the most common crash case
Developers should not rely on the presence of the
functionality provided by this extension. DTS and
Evangelism are investigating licensing this extension to
developers for redistribution. We'll post an announcement
and update this Technote when we resolve all the issues.