Macintosh IIci: Launching Microsoft Word 4.0 Causes Bomb



A customer has a Macintosh IIci with System Software 6.0.4 on a network
using a 3COM card running AppleTalk Phase 2. Occasionally, when launching
Microsoft Word 4.0, his system locks. This happens approximately 50% of
the time. The exact same setup on his Macintosh IIcx does not produce the
problem.

Microsoft Word, version 4.00b or later fixes the compatibility problem
with the Macintosh IIci. All Macintosh IIci users should upgrade their
copy of Microsoft Word to version 4.00b (or later). Apple also recommends
that Macintosh IIfx, Macintosh LC, Macintosh Classic, and Macintosh IIsi
users upgrade to version 4.00b (or later). This upgrade is available by
calling Microsoft Customer Service. To locate a vendor's address and
phone numbers, use the vendor name as a search string.

The problem details are:

Microsoft uses a synthetic handle (a "fake" rgnHandle) when doing
certain operations involving drawing icons in the menu bar. The new,
24-/32-Bit Memory Manager in the Macintosh IIci does additional error and
validity checks on all handles that it operates on. Due to Microsoft
Word's placement in memory, this may cause a variety of apparently random
crashes.

Often fake handles, built on the stack, point into I/O space if these
handles have been incorrectly translated by the Memory Manager. The read
access made to validate its zone header is probably what's causing the
crashes. The Memory Manager does load a bus error handler on unused NuBus
slots, so when the machine crashes, it is probably because the fake region
is pointing at his 3COM card.


Published Date: Feb 18, 2012