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From: cmcmanis@sun.uucp (Chuck McManis)
Newsgroups: comp.sys.intel
Subject: Re: POPF still broken in 286?
Message-ID: <9778@sun.uucp>
Date: Mon, 1-Dec-86 15:39:42 EST
Article-I.D.: sun.9778
Posted: Mon Dec  1 15:39:42 1986
Date-Received: Tue, 2-Dec-86 02:07:47 EST
References: <2646@gitpyr.gatech.EDU> <405@intsc.UUCP> <83@reality1.uucp>
Organization: Sun Microsystems, Inc.
Lines: 33
Summary: Huh?

In article <83@reality1.uucp>, james@reality1.uucp (james) writes:
> Well, what's the most current rev. level for the 80286, ie, how recent
> should mine be to avoid all known bugs?  Chip bugs are normally top secret,
> but I assume the the current chip rev. level isn't sensitive.
James, I don't think chip bugs are "top secret", ask your Intel sales rep
for an Errata sheet. They can also generally tell you the current rev
level or 'stepping' as the semiconducter trade likes to refer to it as.

> 
> Well, gee, I can't think of any bugs in the MC68020 (not XC68020) offhand,
> although the argument might be that they haven't been found yet, or that
> Motorola has had better luck hiding them than Intel has had.  Of course,
> the 68000 did have the bug with the status register in which you could read
> the priviledge level directly from user mode (although this was later
> documented as a feature :-).

Well gee, I bet you couldn't think of any '286 bugs offhand if you hadn't
actually been bit by one. CPU's in general are getting so complicated
that the time to test every transistor in a 32 bit CPU can often be 
measured in hours, one of the biggest challenges facing a Production 
Engineer is to get that testing time down as low as possible. And yes
were bugs in the 68020, and consider that the '286 is both a CPU and
a MMU in one package and compare it against the '020 and '451 or '851.
It is all quite silly, 99% of the 'bugs' are so obscure that they
are *never* seen by 99% of the users. 

For a sobering look at the problems of testing VLSI look at some of the
recent Digital Design, EDN, and other technical mags. 

-- 
--Chuck McManis
uucp: {anywhere}!sun!cmcmanis   BIX: cmcmanis  ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.