Mersenne Digest Friday, November 2 2001 Volume 01 : Number 899 ---------------------------------------------------------------------- Date: Wed, 31 Oct 2001 09:43:27 -0800 From: "Aaron Blosser" Subject: RE: Mersenne: [Fwd: Luke Welsh's Email Address] Luke: I'd volunteer to host a site for you in the short term if you were interested... I'd also volunteer to host the Mersenne list on our mail server since our mail server has a license for unlimited lists, browse-able archives, etc. Just holler. > -----Original Message----- > From: mersenne-invalid-reply-address@base.com [mailto:mersenne-invalid- > reply-address@base.com] On Behalf Of Halliday, Ian > Sent: Wednesday, October 31, 2001 8:38 AM > To: mersenne@base.com > Subject: Mersenne: [Fwd: Luke Welsh's Email Address] > > Luke, the list owner, is in the process of changing hosting services. I > haven't heard from him since he sent me the following, which suggests > that the link is dead, but that he will be sorting it out. > > Regards, > > Ian > > -------- Original Message -------- > Subject: Luke Welsh's Email Address > From: Luke Welsh > > Hello Everybody-- > > Well, it looks line my dear, old, original ISP is finally calling it > quits. > > Sad. > > Soon my personal email address, Luke@SCruzNet.com, will cease to exist. > > I'll find a new home for my Mersenne pages, link-rot and all. But this > may not happen for some time. I will try to get a larger disk quota > so I can host the Mersenne-Digest mailing list archives. > > On the plus side, my spam-o-meter should register somewhat lower :-) _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 31 Oct 2001 19:56:03 -0000 From: bjb@bbhvig.uklinux.net Subject: Re: SV: Mersenne: number of processors participating On 30 Oct 2001, at 14:39, John R Pierce wrote: > near as I can guess, the issue here is that Prime95 is running a few > priority notches above idle and when another process tries to run at a > lower priority it will stall behind prime95. > Well - a process that keeps being preempted will tend to rise in priority & a process that keeps preempting will tend to fall (unless it's running at "real time" priority) - so that might explain it. Reducing the timeslice would still help in the "steady state" when continuous heavy I/O is occurring, by reducing the proportion of the time the compute-intensive process has the CPU. Regards Brian Beesley _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 31 Oct 2001 19:56:03 -0000 From: bjb@bbhvig.uklinux.net Subject: Re: Mersenne: Re: number of processors participating On 30 Oct 2001, at 23:28, Steinar H. Gunderson wrote: > 200ms? Wouldn't this be an error? I can't really imagine that one > would typically have only five time slices per second :-) No, it's the right order of magnitude. The table I have to hand (for a 300 MHz UltraSparc IIi running Solaris 2.6) has a whole bundle of values for different priority levels - 80+ excluding the real-time ones! - - they range from 10 mS to 750 mS. There was a drop in these values during the 80s and early 90s but they had to increase again when processors started depending heavily on cache - task switching tends to trash caches. Also as processors gain more & more registers etc. the number of clocks required to save & restore process contexts tends to increase. This balances out the increasing speed of processors to a considerable extent. The point is that a process which becomes computable as a result of I/O completion etc. at a higher priority than the currently executing process will pre-empt even before the minimum timeslice has expired. If you have a lot of I/O going on then process switching will occur hundreds or thousands of times per second. If you have no I/O going on then it really doesn't matter how infrequently task switching occurs, as you have no means of telling the internal state of the system without I/O occurring. Regards Brian Beesley _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 31 Oct 2001 17:52:29 -0500 From: Michael Vang Subject: Re: Mersenne: Re: number of processors participating > There was a drop in these values during the 80s and early 90s but > they had to increase again when processors started depending > heavily on cache - task switching tends to trash caches. Also as > processors gain more & more registers etc. the number of clocks > required to save & restore process contexts tends to increase. This > balances out the increasing speed of processors to a considerable > extent. Brian- What if you had a dedicated Prime95 box and you set the timeslice at 1 second or even higher (If that is possible...)? If you killed every other thread and process possible wouldn't this show a dramatic increase in performance? I know it is possible to set it very low... I think a previous box I had could go as low as 5ms and doing that made a serious difference in task-switching responsiveness at a loss of overall performance... I think the default value was 20ms on this box (KT133)... Thanks! Xyzzy [83/114.516/124/8.132/770.18] http://www.teamprimerib.com/ _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 01 Nov 2001 15:31:30 +0100 From: Henk Stokhorst Subject: Mersenne: server assigned factoring only. L.S., If I read the status page, it looks like as if the server does not re-assign exponents for factoring only that have expired. Is that a correct conclusion or am I missing something? By now there are several thousands of exponents available below 18.000.000. If so, is that a new policy? YotN, Henk Stokhorst _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 1 Nov 2001 21:55:27 +0000 (GMT) From: Russel Brooks Subject: Mersenne: Prime95 v21 Based on info in recent threads I upgraded from v20 to v21 on my PIII 866MHz Win2K machine. I was already part way thru double checking 7054693 and the change reduced my days-to-go from 8.1 to 6.0. Nice improvement! 8xx on the Top Producers list is in sight... Will v21 help a PII 450MHz Win98 doing double checks at all? Cheers... Russ _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 1 Nov 2001 23:35:03 +0100 From: =?utf-8?Q?Torben_Schl=C3=BCntz?= Subject: Mersenne: Strange factor arrived though not calculating it It seems like I have had credit for one factor that I never did: M16871993 with factor: 2224518820603490479 I am the owner of this exponent as it is assigned to me. Yes! But I didn't work on it. If I did it would have been 3rd in the worktodo.ini, and when it arrived I hadn't touch that since two days ago. I noticed this only because it added a factor. If I had just had the time added to my work I wouldn't have noticed. Too many numbers are running in. I suspect I have lost some time on the same account. What is going on? How could anyone else get a number that I had? happy hunting tsc 2*3*5*7*11*13*17*19*23*29*31-1 is prime _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 2 Nov 2001 08:40:12 +0100 From: =?utf-8?Q?Torben_Schl=C3=BCntz?= Subject: SV: Mersenne: Strange factor arrived though not calculating it True. I was a little to fast about that one. The number though looked promising. :-) tsc -----Oprindelig meddelelse----- Fra: Greg Hogan Sendt: fr 02-11-2001 00:10 Til: Torben Schlüntz Cc: Emne: RE: Mersenne: Strange factor arrived though not calculating it > happy hunting > tsc > > 2*3*5*7*11*13*17*19*23*29*31-1 is prime I am getting 200560490129 = 228737 * 876817. Greg Hogan _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 2 Nov 2001 10:26:20 -0000 From: "Stuart Kennedy" Subject: SV: Mersenne: Strange factor arrived though not calculating it >> happy hunting >> tsc >> >> 2*3*5*7*11*13*17*19*23*29*31-1 is prime >I am getting 200560490129 = 228737 * 876817. >Greg Hogan true but 2*3*5*7*11*13*17*19*23*29*31+1 is prime and 2*3*5*7*11*13*17*19*23*29*31*37*41-1 is prime 2*3* ... *89-1 is prime 2*3* ... *317-1 is prime 2*3* ... *337-1 is prime 2*3* ... *379-1 is prime etc. etc. Stuart Kennedy ________________________________________________________________________ _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 2 Nov 2001 12:13:25 +0100 (CET) From: Henrik Olsen Subject: Re: SV: Mersenne: Strange factor arrived though not calculating it On Thu, 2 Nov 2001, Torben Schlüntz wrote: > On Fri, 2 Nov 2001, Greg Hogan wrote: > > On Fri, 2 Nov 2001, Torben Schlüntz wrote: > > 2*3*5*7*11*13*17*19*23*29*31-1 is prime > > I am getting 200560490129 = 228737 * 876817. > > Greg Hogan On the other hand, 2*3*5*7*11*13*17*19*23*29*31+1 _is_ prime as is 2*3*5*7*11*13*17*19*23*29*31*37*39-1 so you could just use one of those. - -- Henrik Olsen, Dawn Solutions I/S URL=http://www.iaeste.dk/~henrik/ Holder of the special bastard visionary award for debugging unreleased code. (At least according to Sean MacGuire) _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 2 Nov 2001 11:59:44 -0000 From: "Stuart Kennedy" Subject: RE: SV: Mersenne: Strange factor arrived though not calculating it >On the other hand, > 2*3*5*7*11*13*17*19*23*29*31+1 _is_ prime >as is > 2*3*5*7*11*13*17*19*23*29*31*37*39-1 >so you could just use one of those. >Henrik Olsen I wasn't aware that 39 was a prime???????? Stuart Kennedy ________________________________________________________________________ _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 2 Nov 2001 09:47:55 -0800 From: "John R Pierce" Subject: Mersenne: synchronization.. My 'personal report' shows 'exponents returned since last synchronization' going back nearly 12 months (November 2000). Has it really been a year since primenet synched with George's master database?!? - -jrp _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ End of Mersenne Digest V1 #899 ******************************