tester@celerity.UUCP (tester) (07/06/88)
FOR SALE FOR SALE FOR SALE Genuine Intel Coprocessors (is there any other?) Speed up Lotus 123, AutoCAD, etc! 8087-3 $50 80287-6MHZ $100 80287-8MHZ $150 The 80287's are brand new, never been used and are still in the original box. I think that the 8087 has never been used but it is not still in the original box. The 8087 is designed to work at 5MHZ. I've been told that an 8MHZ coprocessor will work in a 10MHZ computer. For the uninformed: the 8087 is designed to be used in an IBM PC/XT or PS/2 models 25 and 30 and compatibles. The 80287's are designed for use in IBM AT's, PS/2 model 50 and 60 and compatibles. Please send mail to (in order of preference) ARPA: UUCP: ee52albh@sdcc5.ucsd.edu [backbone] !sdcsvax!sdcc5!ee52albh pro-sol!dennis@crash.cts.com [backbone] !sdcsvax!crash!pro-sol!dennis daf@shipit.celerity.uucp [backbone] !sdcsvax!celerity!shipit!daf or call Dennis at (619) 535-0655
psc@lznv.ATT.COM (Paul S. R. Chisholm) (07/07/88)
< "Would you buy a used operating system from these guys?" > In article <143@celerity.UUCP>, tester@celerity.UUCP (tester) writes: > FOR SALE FOR SALE FOR SALE >... > 8087-3 $50 >... > The 8087 is designed to work at 5MHZ. >... > For the uninformed: the 8087 is designed to be used in an IBM PC/XT or > PS/2 models 25 and 30 and compatibles. (PS/2-25 compatibles?-) 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 AT&T Mail !psrchisholm, Internet psc@lznv.att.com I'm not speaking for my employer, I'm just speaking my mind.
cjl@ecsvax.uncecs.edu (Charles Lord) (07/08/88)
In article <1400@lznv.ATT.COM>, psc@lznv.ATT.COM (Paul S. R. Chisholm) writes: > > No, I *don't* know what speed a 8087-1 runs at. OK - last time. (Gee, I sound like an anti-drug commercial) 8087 (no dash) 5 Mhz 8087 - 1 10 Mhz 8087 - 2 8 Mhz 8087 - 3 5 Mhz and yes, you can usually push an 80287 up one notch (8 Mhz in 10 Mhz machine). With a heat sink you can sometimes go even further but you risk losing data, accuracy, and the co-processor chip. Hope this helps. -- Charles Lord cjl@ecsvax.UUCP Usenet Cary, NC cjl@ecsvax.BITNET Bitnet #include <std.disclamers> #include <cutsey.quote>
suh@cunixc.columbia.edu (Kenneth Suh) (07/09/88)
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 Kermit Distribution SY.SUH@CU20B.BITNET Columbia University Center for ..!rutgers!columbia!cunixc!suh Computing Activities 612 West 115th Street New York, NY 10025
Ralf.Brown@B.GP.CS.CMU.EDU (07/09/88)
In article <5371@ecsvax.uncecs.edu>, cjl@ecsvax.uncecs.edu (Charles Lord) writes: }and yes, you can usually push an 80287 up one notch (8 Mhz in 10 Mhz }machine). With a heat sink you can sometimes go even further but you }risk losing data, accuracy, and the co-processor chip. Most ATs and AT clones run the coprocessor at 2/3 the speed of the CPU, thus a 12 MHz machine runs the 287 at 8Mhz. -- UUCP: {ucbvax,harvard}!cs.cmu.edu!ralf -=-=-=- Voice: (412) 268-3053 (school) ARPA: ralf@cs.cmu.edu BIT: ralf%cs.cmu.edu@CMUCCVMA FIDO: Ralf Brown 1:129/31 Disclaimer? I |Ducharm's Axiom: If you view your problem closely enough claimed something?| you will recognize yourself as part of the problem.