[comp.arch] Compaq find problem with chip

des@yatton.inmos.co.uk (David Shepherd) (10/30/89)

Friday's (27oct89) Financial Times had an article headlined

	"Compaq shares drop as it finds `problem' with chip"

Brief summary: Compaq announced that it had found problem with fpu on
an Intel chip it is using in its new generation PCs. An analyst is
quoted as saying "You could just hear an audible gasp in the crowd when
they made the announcement". The result of this was a 10% fall in the
value of Compaq stocks and 5% fall in Intel stocks. Neither company was
clarifying what the problem or its implications actually were.

Anyone got any more info on what's happenning .... I assume its the
80486 at fault.

david shepherd
INMOS ltd

ps Compaq just seem to be unlucky when it comes to Intel fpus .... they
got very bored with waiting for correct 80387s as well ;-)

ok@cs.mu.oz.au (Richard O'Keefe) (10/31/89)

In article <2725@ganymede.inmos.co.uk>, des@yatton.inmos.co.uk (David Shepherd) writes:
> Brief summary: Compaq announced that it had found problem with fpu on
> an Intel chip it is using in its new generation PCs. An analyst is
> quoted as saying "You could just hear an audible gasp in the crowd when
> they made the announcement". The result of this was a 10% fall in the
> value of Compaq stocks and 5% fall in Intel stocks.

Given that Compaq *found* the problem and were honest enough to talk
about it, in a just world their share prices should have *risen*.

dmocsny@uceng.UC.EDU (daniel mocsny) (10/31/89)

Warning: purely frivolous post follows. Technically inclined readers with
important work to do please hit 'n' now.

> In article <2725@ganymede.inmos.co.uk>, des@yatton.inmos.co.uk (David Shepherd) writes:
> > Brief summary: Compaq announced that it had found problem with fpu on
> > an Intel chip it is using in its new generation PCs. An analyst is
> > quoted as saying "You could just hear an audible gasp in the crowd when
> > they made the announcement". The result of this was a 10% fall in the
> > value of Compaq stocks and 5% fall in Intel stocks.

With a stock movement of this magnitude, the armchair
conspiratorialist in me has to wonder whether anyone connected with
the fpu bug might have been in position to profit. While I am no
expert in stock futures, I do know that by taking the appropriate
market position, a speculator can wager large sums on various
stock price movements.

A very clean conspiracy scenario is where an engineer surreptitiously
plants a crippling, yet subtle bug that is sure to slip through
preliminary testing. When the bug surfaces late enough in the game to
blow holes in a major product introduction, the resulting stock price
perturbation delivers a handsome profit to the speculators who earlier
gambled that the price would drop. With a company with revenues the
size of a Compaq, we could be talking about enough money to provide
someone with a comfortable early retirement. However, some careful
laundering would be necessary, and if the firm knew who was
responsible for the bug, (s)he would have a most difficult time
enjoying the loot anytime soon. Also, if the bug got caught and fixed
too early, the speculators would take a sizable bath, and might do
something very unpleasant to their co-conspirator as a result.

Disclaimer: I have no connection with any of the above firms, except
as a rabidly satisfied customer, and neither do I have the slightest
shred of evidence for any of the above statements. The above is purely
speculation of the most pathetic armchair variety, and no doubt is
riddled through with factual errors and conceptual distortions.
Furthermore, I am vaguely aware of the strict ethical standards that
all the organizations and their personnel doubtless uphold to the
letter, which would prevent even the thought of such a heinous scheme
from ever occurring. (I sleep better thinking that.) And of course
my employer would instantly pretend to not know me if any of this
got back to them... :-)

But it would make a great movie...

Dan Mocsny
dmocsny@uceng.uc.edu

dolf@idca.tds.PHILIPS.nl (Dolf Grunbauer) (10/31/89)

>In article <2725@ganymede.inmos.co.uk>, des@yatton.inmos.co.uk (David Shepherd) writes:
> Brief summary: Compaq announced that it had found problem with fpu on
> an Intel chip it is using in its new generation PCs.

What is the actual problem ? What chips 80486 and/or 80487 ?
Could someone give more details or did they only say there is a problem
and not what the precise problem is ?
-- 
Dolf Grunbauer          Tel: +31 55 433233  Internet dolf@idca.tds.philips.nl
Philips Telecommunication and Data Systems  UUCP ....!mcvax!philapd!dolf
Dept. SSP, P.O. Box 245, 7300 AE Apeldoorn, The Netherlands
           --> Holland is only 1/6 of the Netherlands <--

ron@woan.austin.ibm.com (Ronald S. Woan) (10/31/89)

In article <443@ssp1.idca.tds.philips.nl>, dolf@idca.tds.PHILIPS.
Grunbauer) writes:
> What is the actual problem ? What chips 80486 and/or 80487 ?
> Could someone give more details or did they only say there is a problem
> and not what the precise problem is ?

According, second hand, to the San Jose Mercury news 27 Oct 89, a defect 
causes incorrect calculations given a rare sequence of floating point
operations. Ghastly!

						Ron

+------All Views Expressed Are My Own And Are Not Necessarily Shared By-------+
+-------------------------------My Employer-----------------------------------+
+ Ronald S. Woan    (IBM VNET)WOAN AT AUSTIN, (AUSTIN)ron@woan.austin.ibm.com +
+ outside of IBM         @cs.utexas.edu:ibmaus!auschs!woan.austin.ibm.com!ron +

terrell@cadnetix.COM (Eric Terrell) (11/01/89)

What was the reaction to the announcement of the 32 bit multiply error in the 386?


Terrell

mslater@cup.portal.com (Michael Z Slater) (11/01/89)

The bug 
Compaq referred to was in the FPU on the 486.  It occurs only under very
specific and rare conditions.  Intel says only that a customer found it,
and won't identify which one; Compaq says it was them.  An indication of
how obscure the bus is is that the 486 passes all of Intel's test suites
for the 387.

Intel says that they have engineered the fix, and will have corrected
parts by the end of November.

Michael Slater, Microprocessor Report   mslater@cup.portal.com

ed@imuse.intel.com (Ed Braaten) (11/02/89)

In article <443@ssp1.idca.tds.philips.nl> dolf@idca.tds.PHILIPS.nl 
(Dolf Grunbauer) writes:

>What is the actual problem ? What chips 80486 and/or 80487 ?

What is an 80487???  Do you know something I don't know?

Ed

-------------------------------------------------------------------------
        Ed Braaten            | "Love the Lord your God with all your
Internet: ed@imuse.intel.com  |  heart and with all your soul and with 
   EUnet: unido!imuse!ed      |  all your strength."  Deuteronomy 6:5 
-------------------------------------------------------------------------

davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) (11/02/89)

In article <10136@cadnetix.COM>, terrell@cadnetix.COM (Eric Terrell) writes:
|  
|  What was the reaction to the announcement of the 32 bit multiply 
|  error in the 386?

  I don't think there's a correlation. The 386 (at the time the multiply
bug was found) was being primarily used for DOS, and most applications
didn't use the 32 bit instructions. The problem with the might be found
in any o/s, at least as described in the magazines.

  Personally, *if* Intel is telling us the truth, I see no problem. They
claim to have a mask revision, they say they will have it in place by
the end of the month, and they say they can still ship production
quantities this year.

  While I would not hesitatte to use one of the old 386's in a 16 bit
environment (with the machine properly labeled of course) I would not
use one of the flawed 486's for anything. I sort of hope I can persuade
Intel to give me one, even burned out if they wish, for a big hi-tech
tie tack ;-)
-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
"The world is filled with fools. They blindly follow their so-called
'reason' in the face of the church and common sense. Any fool can see
that the world is flat!" - anon

conor@inmos.co.uk (Conor O'Neill) (11/03/89)

Reproduced from Electronics Weekly, Wed, November 1, 1989, front page:
(without permission)

Two design faults have been discovered in Intel's million transistor 80486
microprocessor chip which was first unveiled last April and has been in
production since August.

Both faults are in the chip's floating point unit: one affects its ability
to correctly calculate trigonometrical functions such as tangents, cosines
and sines; while the other (in the exception handling detection system)
affects the floating point unit's ability to detect whether a particular
calculation makes sense.

"We've already shipped thousands of chips and yes if people ask for
replacements we will do it," said an Intel spokeswoman. Intel has 
redesigned the chip, made new masks and is now manufacturing a new version
of the 80486 which is free of these two bugs, she added.


[end of article]

As usual, not enough information for anyone to use.



-- 
Conor O'Neill, Software Group, INMOS Ltd., UK.
UK: conor@inmos.co.uk		US: conor@inmos.com
"It's state-of-the-art" "But it doesn't work!" "That is the state-of-the-art".

joel@nosun.UUCP (Joel Clark) (11/04/89)

In article <443@ssp1.idca.tds.philips.nl> dolf@idca.tds.PHILIPS.nl (Dolf Grunbauer) writes:
>>In article <2725@ganymede.inmos.co.uk>, des@yatton.inmos.co.uk (David Shepherd) writes:
>> Brief summary: Compaq announced that it had found problem with fpu on
>> an Intel chip it is using in its new generation PCs.
>
>What is the actual problem ? What chips 80486 and/or 80487 ?
>Could someone give more details or did they only say there is a problem
>and not what the precise problem is ?
>-- 
>Dolf Grunbauer          Tel: +31 55 433233  Internet dolf@idca.tds.philips.nl
>Philips Telecommunication and Data Systems  UUCP ....!mcvax!philapd!dolf
>Dept. SSP, P.O. Box 245, 7300 AE Apeldoorn, The Netherlands
>           --> Holland is only 1/6 of the Netherlands <--


From DATAQUEST information services.

 80846 CHIP FIX
  At its quarterly financial analyst meeting held on October 26, Intel announced
that it was officially releasing availability information on its 80486 32-bit
microprocessor, on which an error resulting from a floating point operation had
been discovered.  Dave House, general manager of the microcomponents group
essentially described the problem as "obscure".  The error affects floating
point tangent and exception handling and arises when the floating point
instruction is handling exact powers of 2 and when the instruction is followed
by a particular sequence of instructions.  Readers may recall that in its
implementation of the 80486, Intel had incorporated the floating point unit
on-chip.  Discovery of the error result was made after 100,000 hours of testing
performed by Intel and some of its major customers who had received early
shipment of the device.  Once Intel had verified the problem at the chip level,
the company proceeded to notify customers on Friday, October 20th.  Intel is in
the process of implementing a fix on the mask set and expects to have evaluation
product from the revised masks next week.  In the meantime, shipments of the
80486 are on-hold.  Many wafers in production had not yet reached the final
metalization stage, and so are being held prior to metalization pending the new
masks.  Production will resume in November and the company still expects to ship
tens of thousands of the 80486 during the fourth quarter.  Intel policy with
respect to the flawed devices is to offer its customers replacements.  Intel
will continue to supply the defective 80486 to customers wishing to go ahead and
use the device.  Many business applications will not be affected by the floating
point error.  The floating point tangent operation is a new instruction not
featured on the original 8087 math-coprocessor.  Moreover, some workarounds have
been developed to handle the resulting floating point error which may arise in
scientific and technical applications.  Resolution of this problem will not
impact Intel as severely as the problem the company had with the 80386, largely
because the problem was discovered at an early stage.  In the case of the math
errors occurring on the 80386 were discovered over a year after shipments had
commenced.  Shipments of the 80486 had only begun early in the third quarter,
and most customers have not yet released their products based on the chip.
Therefore, the number of devices affected is smaller and substitution will be
simplified by the relatively low extent of distribution.  Intel stated that this
problem would not affect anticipated fourth quarter financials, which had
previously been characterized as providing modest revenue growth.

joel clark
intel scientific computers
joel@intelisc.intel.com
(503) 629-7732

c9h@psuecl.bitnet (11/07/89)

In article <2800@ganymede.inmos.co.uk>, conor@inmos.co.uk (Conor O'Neill) writes:
> "We've already shipped thousands of chips and yes if people ask for
> replacements we will do it," said an Intel spokeswoman. Intel has
> redesigned the chip, made new masks and is now manufacturing a new version
> of the 80486 which is free of these two bugs, she added.
>
> [end of article]
>
> As usual, not enough information for anyone to use.

Not enough information?  What the Hell do you want?  They offered to replace
the chips, for Christ's sake!  Jesus!  Some people are never satisfied!

('scuse me, but stupidity really irks me!)

--
- Charles Martin Hannum II       "Klein bottle for sale...  Inquire within."
    (and PROUD OF IT!!!)         "To life immortal!"
  c9h@psuecl.psu.edu             "No noozzzz izzz netzzznoozzzzz..."
  cmh117@psuvm.psu.edu           "Memories, all alone in the moonlight ..."

toms@omews44.intel.com (Tom Shott) (11/07/89)

There us no such chip as the i487. The functionality of the i387 was
improved and integrated into the i486. Some improved functionality resulted
from a tighter integration of the FPU into the processor. (How faults and
exceptions are handled.) Floating point performance was improved 3-4X
compared to a i387 due to reduced number of cycles for some operations.

Disclamer: I DO work for Intel. I had nothing to do w/ the i486. The
information stated is from the Intel i486 data sheet (book). 


--
-----------------------------------------------------------------------------
Tom Shott    INTeL, 2111 NE 25th Ave., Hillsboro, OR 97123, (503) 696-4520
	     toms@omews44.intel.com OR toms%omews44.intel.com@csnet.relay.com
	INTeL.. Designers of the 960 Superscalar uP and other uP's

kenobi%lightsabre@Sun.COM (Rick Kwan) (11/07/89)

In article <2800@ganymede.inmos.co.uk> conor@inmos.co.uk (Conor O'Neill) writes:
>Reproduced from Electronics Weekly, Wed, November 1, 1989, front page:
>(without permission)
>
>Two design faults have been discovered in Intel's million transistor 80486
>microprocessor chip which was first unveiled last April and has been in
>production since August.
>
>Both faults are in the chip's floating point unit: one affects its ability
>to correctly calculate trigonometrical functions such as tangents, cosines

Anyone know:
    1.	how long (man-years and/or calendar years) it took to write
	the test vectors to exercise the 486, and roughly how many
	vectors are involved?  (I heard that the 386 took 3 years.)
    2.	what kind of system was used for testing (Trillium, Sentry,
	or what)?

I assume this is an absolutely full-custom chip.  Yes?

	Rick Kwan
	Sun Microsystems - Intercontinental Operations
	kenobi@sun.UUCP or kenobi%lightsabre@sun.COM

scott@bbxsda.UUCP (Scott Amspoker) (11/08/89)

In article <63979@psuecl.bitnet> c9h@psuecl.bitnet writes:
>In article <2800@ganymede.inmos.co.uk>, conor@inmos.co.uk (Conor O'Neill) writes:
>> [Intel announces that mysterious 486 bug has been fixed]
>>
>> As usual, not enough information for anyone to use.
>
>Not enough information?  What the Hell do you want?  They offered to replace
>the chips, for Christ's sake!  Jesus!  Some people are never satisfied!

I agree with Conor.  I want to know exactly what the problem was.  It
is not enough that Intel will ship new 486 chips.  When I have a customer
on the phone complaining about a bug in our software I want to recognize
the symptoms of an early 486 that somehow did not get updated.

-- 
Scott Amspoker
Basis International, Albuquerque, NM
(505) 345-5232
unmvax.cs.unm.edu!bbx!bbxsda!scott

andrew@dtg.nsc.com (Lord Snooty @ The Giant Poisoned Electric Head ) (11/12/89)

I believe the Weitek 4167 (?) boosts 80486 fpt performance by "a factor of
3 or 4". In any case, how does the coupled 80486/4167 system decide which
fpt unit will execute a given fpt instruction? and is this a way around the
bug, temporarily - in that the Weitek would take over the sin/cos/tan stuff?

-- 
...........................................................................
Andrew Palfreyman	a wet bird never flies at night		time sucks
andrew@dtg.nsc.com	there are always two sides to a broken window

darryl@ism780c.isc.com (Darryl Richman) (11/12/89)

In article <291@berlioz.nsc.com> andrew@dtg.nsc.com (Lord Snooty @ The Giant Poisoned Electric Head       ) writes:
"I believe the Weitek 4167 (?) boosts 80486 fpt performance by "a factor of
"3 or 4". In any case, how does the coupled 80486/4167 system decide which
"fpt unit will execute a given fpt instruction? and is this a way around the
"bug, temporarily - in that the Weitek would take over the sin/cos/tan stuff?

The Weitek is memory mapped device and works on a completely different
instruction set than the x87.  You can actually configure asystem and get
all three processors running in parallel.  To use a Weitek, you need to
compile for it in advance, and if you don't have one (or an emulator),
such a binary is useless.

		--Darryl Richman
-- 
Copyright (c) 1989 Darryl Richman    The views expressed are the author's alone
darryl@ism780c.isc.com 		      INTERACTIVE Systems Corp.-A Kodak Company
 "For every problem, there is a solution that is simple, elegant, and wrong."
	-- H. L. Mencken