Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!cernvax!chx400!chx400!urz.unibas.ch!ganter
From: ganter@urz.unibas.ch
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Various 486 questions
Message-ID: <1991Feb21.142350.1389@urz.unibas.ch>
Date: 21 Feb 91 13:23:50 GMT
References: <708.27c232c6@malibu.sedd.trw.com>
Organization: University of Basel, Switzerland
Lines: 41

In article <708.27c232c6@malibu.sedd.trw.com>, rose@malibu.sedd.trw.com writes:

> 1) I have seen a lot of recent price drops in 486/25 machines.
..stuff deleted...
> Is there any specific
> reason that prices have dropped so drastically recently? And 
> any opinion on whether these prices will continue down or start
> back up?

I think, there are still some 486/25 with B9 mask around. These are
told to have bugs, that prohibit multiprocessor use without external
logic (delivered by Intel with the processor). The main problem wouldn't
be the actual processor, but an eventual newer one (connect pin x with 
ground ..., etc). I don't think, that a C1 or higher would run in such
an environement. Because of these bugs, the machines containing them are
sometimes much cheaper. If You are kind with Your B9-486 all that stuff
perhaps doesn't matter for You. But I'd be carefull.
Another reason is certainly the 486/33 entering the market now.
 
>    Does the 486 machine truly contain a built in math co-processor?
> Will "any" software that requires or can use a co-processor
> be able to run on the 486?  If the above is true: then why does 
> Tri-Star advertise a "CAD" system which contains an 80387?
> This was in the computer shopper.  The system contains a digitizer
> in addition to the basic computer.

Yes, the 486 contains a full 387 coprocessor. The 486 built in FPU is faster 
(i.e. fever clock counts for some instructions) and has the same parallel
facilites as the 386/387 processors have. 
Perhaps the 387 is meant as the built in 387 (Or do they use a second one
only for the digitizer part ?).

Most 486 boards have a second socket for the Weitek 4167 FPU (not compatible
to the 387, but faster).
 
Robert

Robert Ganter
University of Basel
Switzerland
ganter@urz.unibas.ch