koziarzw@LONEX.RADC.AF.MIL (Walter Koziarz) (07/19/89)
I wrote: >>The 10MHz clock-rate tinker seems (from my fractal-image oriented perspective) >>to be much more worth pursuing. The only real question I am still uncertain >>of with regard to 10MHz is whether the PALs on the 8087 board can keep-up. Ken (absolutely correctly) responds: >Another serious consideration here is the 8087 itself, which is >particularly prone to heat (hence speed) related problems. When I >increased the speed on my 100 from 5 to 8 Mhz, I found that the >machine would lock up at odd times, unpredictably. I put in an 8088-2 >(8 Mhz model) and that improved the situation slightly, then I put in >an 8087-2 (when the prices were ~$100) and voila - no more lockups, >ever. The PALs, while probably not rated for 8 Mhz operation, had no >problem whatsoever. My H-100 continues to run at 8 Mhz with 100% >reliability (knock on wood...). >Ken >Kenneth R. van Wyk >Technical Coordinator, Computer Emergency Response Team >Software Engineering Institute >Carnegie Mellon University >Internet: <krvw@SEI.CMU.EDU> I had ommitted the statements that an integral part of the 10MHz work is acquiring an 8088-1 and an 8087-1. These are both rated for 10MHz operation. Gern also suggests replacing the clock generator (8284) with a newer 10MHz rated part (8284-1, I think). Appologies for any confusion!!! BTW, Ken, are you using the ORIGINAL PALs from the 5MHz 8087 board? Cheers, Walt K.
krvw@sei.cmu.edu (Kenneth Van Wyk) (08/16/89)
In article 10MHz 8087 & 8088 of 19 Jul 89 14:50:58 GMT koziarzw@LONEX.RADC.AF.MIL (Walter Koziarz) writes: >BTW, Ken, are you using the ORIGINAL PALs from the 5MHz 8087 board? Yes, I am. I'm using the UCI 8 Mhz speed upgrade, and the only other things that I changed on the machine were the RAM PALs (for 256k DRAMS), the DRAMS themselves, and the processors. The only peculiarity which I've run into is that CP/M (85 and 86) won't access the hard drives at 8 Mhz, but MS-DOS (3.1) is fine - must be timing problems in CP/M, IMHO. Ken