[sorry, replying to digests is probably unfriendly, but I can't face hordes of email. Do people mind if I just reply to interesting messages from the digest two-daily or so?] >From: "Pete" <[EMAIL PROTECTED]> >Date: Tue, 10 Nov 1998 18:26:53 -0000 >Subject: Re: Mersenne: windows 98/FAT32 > >Thanks for all the suggestions. >I converted back to FAT16 using Quarterdeck 'Partition-It' and the HDD now >powers down again. >I have set up prime95 to write to disk every 300 minutes. Ah. I'm fairly sure that wasn't necessary, simply because the machine here will power down its hard disc quite happily (though I've disabled it because of the prime95 writes) even under FAT32. >------------------------------ >From: George Woltman <[EMAIL PROTECTED]> >Date: Tue, 10 Nov 1998 13:38:18 -0500 >Subject: Re: Mersenne: New features of Prime95 (v. 17) output >The fourth value is a count of "SUM(INPUTS) != SUM(OUTPUTS)" messages. Should I assume that, if I've received one of these messages, my run is clearly invalid and should be restarted, or has the computer just gone back to a previous save file or to the previous value and carried on? [I think there's still some MMX code around which doesn't clear up properly after itself ... why didn't Intel mandate saving and restoring the MMX registers on context switch?] >------------------------------ >From: Blake Stacey <[EMAIL PROTECTED]> >Date: Wed, 11 Nov 1998 10:49:20 -0600 >Subject: Mersenne: Re: Thoughts > >I agree that modeling nuclear detonations take a lot of computing >power. However, I'm pretty sure that this couldn't be done on a distributed >parallelistic basis. (Is that even a word--parallelistic?) >For the life of me, I can't figure out how to distribute the >mathematics. It seems that each region of the space where the explosion >is happening needs constant information from most of the others (or >maybe just those directly adjacent). You don't need information from everywhere, just from adjacent regions - so you partition the space into 48 regions, one per 128-processor SGI supercomputer (if Blue Pacific is the one I'm thinking of, otherwise s/SGI/IBM), and at each tick you need only pass the boundary data across the insanely fast interconnect. Remember, the interconnects in something like Blue Pacific are three orders of magnitude faster than the Internet bandwidth, and at least one order of magnitude more than the total trans-Atlantic bandwidth; I'd not be startled if a single run on Blue Pacific involved more communication than the Internet to date. >------------------------------ > >From: Yuri Sorkin <[EMAIL PROTECTED]> >Date: Wed, 11 Nov 1998 22:48:37 -0800 (PST) >Subject: Mersenne: What computer is OK today? > >I participated in GIMPS from the very beginning, yet trying to join it with >386-SX. And now I see that my P5-166 (SDRAM, MMX, Intel) doesn't get >from Primenet anything for LL-test quite awhile. Since I'm going to buy a >new desktop soon and consider its suitability for GIMPS to be a certain >indicator of satisfactorily performance, I wonder what computers get >exponents for a test now? Four months back? I'm being fed exponents to LL-test on a P2/350 - I'd recommend you get a BX motherboard and a large pile of SDRAM, start with a P2/350 or even an overclocked Celeron if you want to live dangerously, and expect to upgrade when Intel give away Katmais in cornflake packets. Tom
