Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!elroy.jpl.nasa.gov!thyme!kaleb
From: kaleb@thyme.jpl.nasa.gov (Kaleb Keithley)
Newsgroups: comp.sys.intel
Subject: Re: 287 on a 386 machine
Message-ID: <1991Jan9.182709.19418@thyme.jpl.nasa.gov>
Date: 9 Jan 91 18:27:09 GMT
References: <1991Jan9.004654.21586@research.canon.oz.au> <1991Jan9.180643.14310@magnus.ircc.ohio-state.edu>
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 29

In article <1991Jan9.180643.14310@magnus.ircc.ohio-state.edu> smsmith@hpuxa.ircc.ohio-state.edu (Stephen M. Smith) writes:
>graeme@research.canon.oz.au (Graeme Wong See) writes:
>>I was recently in a computer store where I saw a brochure for a 386
>>motherboard (can't remember if it was a DX or SX motherboard) from Taiwan.
>>In the specs under coprocessors it says that it can take either a 287 
>>or a 387 maths coprocessor. Is this at all possible with either a DX or SX?
>>Perhaps it is a typo but any clarification on the matter will be helpful.
>
>Over Christmas break I rented a 386 computer with this very configuration.
>When the sales rep told me it had a 287 installed I attempted to correct
>him by saying that he must mean a *387*, but he said that it did in
>fact have a *287* on board because the motherboard was socketed for 
>both the 287 and the 387.  When I got the computer home I opened it
>up and sure enough, there was the rectangular 287 on the motherboard
>and there was a square socket for a 387 to be added as well.  I don't
>know how the 386 chip uses the 287--perhaps this can only be done
>on a 386sx (I don't remember if this computer was an SX or a DX-20).
>

Early 386 boards were socketed for both the 287 and the 387 because
early production quantities of 387s were very small.  These were, and are
386DX boards, the SX didn't even come out for over a year after the DX
was shipping in production quantities.

-- 
Kaleb Keithley                      Jet Propulsion Labs
kaleb@thyme.jpl.nasa.gov

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