Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!gatech!bloom-beacon!bu-cs!encore!cloud9!dts
From: dts@cloud9.Stratus.COM (Daniel Senie)
Newsgroups: comp.sys.ibm.pc
Subject: Re: 80386 versus 80387
Summary: Go see your dealer
Keywords: 80386, 80387, 80287
Message-ID: <5268@cloud9.Stratus.COM>
Date: 17 May 89 18:42:24 GMT
References: <1427@uw-entropy.ms.washington.edu>
Organization: Stratus Computer, Inc., Marlboro, MA
Lines: 25

In article <1427@uw-entropy.ms.washington.edu>, felsenst@uw-entropy.ms.washington.edu (Joe Felsenstein) writes:
> 
> I have heard that there is a sporadic nasty interaction between 80386's
> and 80387 numeric co-processors, owing to a design flaw in the 80386,
> and that it is not cleared up yet.
> 
> On a Zenith Z-386 I may be having this problem; when the 80387 is used
> there are sporadic unpredictable crashes or operating system
> paralysis (I happen to be using Unix, but if this is the problem that
> may be irrelevant).

This is a well known problem which Intel referred to as Errata 21. Go
see your Zenith dealer. He will give you a new PAL for your CPU board
which completely remedies the situation. It is a bug in the 386, but
a very simple PAL change cures the problem. The DX step of the 386
has this problem fixed.

This problem only occurs when running in 32 bit protected mode. Effectively
the CPU and Co-Processor sit there waiting for each other forever.

-- 
Daniel Senie               UUCP: harvard!ulowell!cloud9!dts 
Stratus Computer, Inc.     ARPA: anvil!cloud9!dts@harvard.harvard.edu
55 Fairbanks Blvd.         CSRV: 74176,1347
Marlboro, MA 01752	   TEL.: 508 - 460 - 2686