Xref: utzoo misc.forsale:1732 comp.sys.ibm.pc:16996
Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!uwmcsd1!bbn!rochester!rutgers!columbia!cunixc!suh
From: suh@cunixc.columbia.edu (Kenneth Suh)
Newsgroups: misc.forsale,comp.sys.ibm.pc
Subject: Re: Intel Coprocessors for sale
Keywords: 8087 80287 IBM
Message-ID: <786@cunixc.columbia.edu>
Date: 8 Jul 88 17:13:57 GMT
References: <143@celerity.UUCP> <1400@lznv.ATT.COM>
Reply-To: suh@cunixc.cc.columbia.edu (Kenneth Suh)
Distribution: na
Organization: Columbia University
Lines: 27

In article <1400@lznv.ATT.COM> psc@lznv.ATT.COM (Paul S. R. Chisholm) writes:
>< "Would you buy a used operating system from these guys?" >
>Um, no.  For a system with an 8 MHz 8088 or 8086 (e.g., AT&T PC 6300,
>original Compaq Deskpro, IBM PS/2 Models 25 and 30), you want an 8 MHz
>8087-2.  The 5 MHz 8087-3 is suitable for 4.77 MHz machines (PC and XT
>compatibles).  That's a good price for an 8087-3, but if it doesn't
>work reliably in your (8 MHz) system, it's no bargain at any price.
>
>No, I *don't* know what speed a 8087-1 runs at.
>
>-Paul S. R. Chisholm, {ihnp4,cbosgd,allegra,rutgers}!mtune!lznv!psc


The 8087-1 was a brain-damaged Intel Math Coprocessor which was 5 MHz.
Also, doesn't the math co-processor run at one-third the boards crystal
speed.  I know that the cpu runs at half the crystal speed on an AT.

/ken

Kenneth Suh                            PATH: suh@CUNIXC.CC.COLUMBIA.EDU
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