Mersenne Digest Friday, March 3 2000 Volume 01 : Number 701 ---------------------------------------------------------------------- Date: Wed, 1 Mar 2000 20:40:35 -0800 From: "John R Pierce" <[EMAIL PROTECTED]> Subject: Mersenne: Williamette Hmm. Microprocessor Reports has released some interesting tidbits about the new Williamette processor which will probably be the Pentium-4... This is the chip Intel recently demonstrated running at 1.5GHz. <begin quote> Willamette will be packaged in flip-chip PGA (FC PGA) and was designed for a socket of between 400 and 500 pins, which Intel referred to as Socket-W. The unnamed Willamette bus is a source- synchronous 64-bit 100MHz bus that is quad-pumped to an equivalent of 400MHz per bit, delivering a total of 3.2GB/s of bandwidth--three times the bandwidth of the fastest Pentium III bus. The chip set for Willamette, code-named Tehama, will be a dual-RAC (RDRAM) design. A unique and unexpected aspect of Willamette's microarchitecture is its "double-pumped" ALUs. Claiming the effective performance of four ALUs, the two physical ALUs are each capable of executing an operation in every half-clock cycle. The anticipated improvements to SSE, called SSE2, were introduced in Willamette, including support for (dual) double-precision SIMD floating-point operations. <end quote> so, its more than just a 1GHz+ P-III design, they've done some significant architectural internal things. And, that double SIMD FPU thing otta rock for LL tests, eh? :D - -jrp _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 02 Mar 2000 13:40:55 -0500 From: George Woltman <[EMAIL PROTECTED]> Subject: Re: Mersenne: Williamette Hi, At 08:40 PM 3/1/00 -0800, John R Pierce wrote: >Hmm. Microprocessor Reports has released some interesting tidbits about the >new Williamette processor which will probably be the Pentium-4... This is >the chip Intel recently demonstrated running at 1.5GHz. Intel has info on this processor at http://developer.intel.com/design/processor/wmtsdg.htm The chip has good potential. The new SIMD2 instructions have the potential of doubling throughput. It also looks like FPU operations can be done in parallel with SIMD2 - that's triple the throughput of a PIII. Not to mention running at 1.5GHz! Of course, time will tell as to how good this processor really is. There could be other bottlenecks, it may not be easy to recode prime95 to use the SIMD2 instructions. The latencies for FPU operations are higher than in the P-III. The FXCH instruction is no longer free. Mispredicted branch penalties are higher, etc. etc. I've not heard any rumors as to a release date, but it looks like I'll have to buy two new computers in the next 12 months. An IA-64 and a Willamette! Regards, George _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 2 Mar 2000 14:01:24 -0500 (EST) From: "St. Dee" <[EMAIL PROTECTED]> Subject: Mersenne: Security and Prime95/mprime Hi, I'll likely be moving to a cable modem soon and intend to install a machine to act as a firewall, likely a Linux box. Since it will be sitting there all day doing nothing other than screening stuff between my LAN and the 'Net, I thought I'd run mprime (if Linux) on it. Of course, all of the security gurus say to run nothing beyond the programs actually needed on the firewall box. Am I creating any security risks by running mprime on the firewall box? I'm sure some of you must be doing that--noticed any problems? Thanks! Kel Utendorf _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 2 Mar 2000 22:36:20 +0000 From: "Steinar H. Gunderson" <[EMAIL PROTECTED]> Subject: Mersenne: Re: Security and Prime95/mprime On Thu, Mar 02, 2000 at 02:01:24PM -0500, St. Dee wrote: >Am I creating any security risks by running mprime on the firewall box? You shouldn't, since mprime doesn't deal with server sockets (only the occasional HTTP traffic to PrimeNet) at all. The only problem I can think of, is that it eats a chunk of your RAM, so a DoS attack would probably be slightly easier (at least if somebody can connect 10000 times to your FTP socket, and inetd fires up a new ftpd dæmon for every new socket). I run it on a 486sx/16 (24MB RAM, though) just fine, and that machine serves 30000 proxy requests (HTTP) a day :-) /* Steinar */ - -- Homepage: http://members.xoom.com/sneeze/ _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 2 Mar 2000 23:10:32 -0000 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: Re: Mersenne: Security and Prime95/mprime On 2 Mar 00, at 14:01, St. Dee wrote: > I'll likely be moving to a cable modem soon and intend to install a > machine to act as a firewall, likely a Linux box. linux is a Good Move ... ceratinly, in its default state, it's at least as secure (when used as a firewall) as anything emanating from a certain purveyor of operating systems based near Seattle. It's cheaper, too! > Since it will be > sitting there all day doing nothing other than screening stuff between my > LAN and the 'Net, I thought I'd run mprime (if Linux) on it. This sounds eminently sensible. > Of course, > all of the security gurus say to run nothing beyond the programs actually > needed on the firewall box. Hey, I'm a security guru of a sort ... the idea is not to run anything which gives crackers a toehold, or causes unacceptable throttling of the firewall throughput. > Am I creating any security risks by running > mprime on the firewall box? I'm sure some of you must be doing > that--noticed any problems? Few of us know what code George has embedded in the code which computes the tag which PrimeNet uses to check that incoming results are genuine. However, this does not seem to present a major risk! Apart from that, what mprime does is very network friendly & seems to present an insignificant risk to operation of a firewall. I've run mprime on an anonymous FTP server for almost 18 months & haven't had any incidents (yet). The basic rules are (a) always run mprime using "nice -n20" to give other processes all the CPU time they need; (b) never run mprime as root; (c) make it harder for any cracker who does get onto your system to exploit any weakness that may be in mprime by running it in a directory with no access to anyone except a user set up specially to run mprime. And make sure shadow passwords are enabled. Recent linux distributions do this by default. All this is virtually paranoia since I believe the risk posed by running mprime is practically nil - but it's good practise, anyway. Regards Brian Beesley _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 02 Mar 2000 19:09:45 EST From: "Nathan Russell" <[EMAIL PROTECTED]> Subject: Mersenne: How much are the 10 M gamblers contributing? Something I've been wondering about since entering this project - How much are the people who are trying to find a 10 million digit prime contributing to the search? They stand less than a tenth the ordinary chance per unit time, and any prime they find will take at least four or five years to definately place in sequence. I do understand that GIMPS' share of the prize money, if any, will go a long way towards maintaining the PrimeNet server, paying developers/porters of the client and so forth, but I just can't help wondering whether the people (It's only about five percent of the userbase, is stats is any guide) who are doing this are contributing. I'm not trying to flame anyone. Currently I am myself about a fifth of the way through two exponents in the 9.3 M range (with a p3-600 win98, if anyone cares), but I do respect that others may have different goals. If I succeed in finding a prime, I will have set a record that will likely stand for a year or two, and it would look great on my resume going into college :-) (I have taken some advanced math courses at the Rochester Institute of Technology while a high school student, if anyone is confused) I would certainly be more than happy if I found a prime, and even if I never do (which is quite likely) I will be content to have helped this project and to have sped up somewhat the efforts of whomever does win. After all, without each failure, the winner would have been delayed by one exponent. Another question, on a slightly different note: How likely is it that the cutting edge, so to speak, of the main first-time LL effort will check all the exponents up to 10 million before a 10 million digit prime is found? We're about a third of the way there now in terms of exponents, about halfway or more when you rule out composite exponents and I have no clue how close in terms of actual P90 time. Please, feel free to correct me if I made some factual errors - I have been, after all, only here eleven days. ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 3 Mar 2000 00:01:34 +0000 From: "Steinar H. Gunderson" <[EMAIL PROTECTED]> Subject: Mersenne: Re: Williamette On Thu, Mar 02, 2000 at 01:40:55PM -0500, George Woltman wrote: >The new SIMD2 instructions have the potential of doubling throughput. But why would Intel market these instructions as `multimedia' instructions? Surely no normal MM tasks would need double precision. Of course, I shouldn't complain :-) >The FXCH instruction is no longer free. Is SIMD2 (or SSE2, or whatever Intel likes to call it) _still_ stack-based? I thought Intel should have learned by now? By the way, if the registers are not aliased upon the FP registers, what will Intel do with the task switch problem? Back when MMX was new, I heard the reason for aliasing the MMX registers upon the FP registers was that no OS change would be neccessary (to save/restore the registers). >Mispredicted branch penalties are higher, etc. etc. Any idea why? BTW, branching when there is two different sets of code (running in parallel) to take care of will be quite interesting :-) /* Steinar */ - -- Homepage: http://members.xoom.com/sneeze/ _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 02 Mar 2000 19:49:20 -0800 From: Spike Jones <[EMAIL PROTECTED]> Subject: Mersenne: searching the biggies 2 - --------------F6938DA8EE944119E0D46EFB Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Nathan asked: How much are the people who are trying to find a 10 million digit prime contributing to the search? Now that you asked, I have been pondering this point. The payoff structure offered by the EFF has in some ways been a hindrance to GIMPS as well as a motivator. It is aesthetically unpleasing to have a big gap in the searched base, however, the "leading edge" will eventually catch up. It should be a straightforward task to estimate when that will be. When the 10E7 Mersenne is found and the 100K EFF prize is awarded, there is no reason to think some yahoos will jump up and try for a 10E8, since it would take over a century on a PII/400. Then, if a gap still exists, it would fill in and those who were trying for the 10E7 will have contributed just as much as anyone else. On the other hand, the existence of the EFF prize is a useful tool in convincing companies to run GIMPS, for most IT managers are quick to remind you that this *is* a business, and it is here to make money. (Then you hope that same IT manager hasnt the sophistication to calculate the actual odds of bagging the $100K, realizing that the mathematical expectation of the prize would not pay the extra electricity use...) spike - --------------F6938DA8EE944119E0D46EFB Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <I>Nathan asked: How much are the people who are trying to find a</I> <BR><I>10 million digit prime contributing to the search?</I> <P>Now that you asked, I have been pondering this point. The <BR>payoff structure offered by the EFF has in some ways been <BR>a hindrance to GIMPS as well as a motivator. It is aesthetically <BR>unpleasing to have a big gap in the searched base, however, <BR>the "leading edge" will eventually catch up. It should be a <BR>straightforward task to estimate when that will be. <P>When the 10E7 Mersenne is found and the 100K EFF prize <BR>is awarded, there is no reason to think some yahoos will <BR>jump up and try for a 10E8, since it would take over a <BR>century on a PII/400. Then, if a gap still exists, it would fill <BR>in and those who were trying for the 10E7 will have contributed <BR>just as much as anyone else. <P>On the other hand, the existence of the EFF prize is a useful <BR>tool in convincing companies to run GIMPS, for most IT <BR>managers are quick to remind you that this *is* a business, <BR>and it is here to make money. (Then you hope that same <BR>IT manager hasnt the sophistication to calculate the actual <BR>odds of bagging the $100K, realizing that the mathematical <BR>expectation of the prize would not pay the extra electricity <BR>use...) spike</HTML> - --------------F6938DA8EE944119E0D46EFB-- _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 02 Mar 2000 19:49:36 -0800 From: Spike Jones <[EMAIL PROTECTED]> Subject: Mersenne: searching the biggies - --------------74585DC7DA00594FC8A87A54 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Nathan Russell asked: How much are the people who are trying to find a 10 million digit prime contributing to the search? Any machine that is running GIMPS is contributing to mapping the great universal math-space. If one is factoring, double checking, finding a slew of Mersenne composites (I know 30 now), searching for 10E7s, regardless, any way you look at it, you are on the team. If we use the orderly system George and Scott have created, we are uncovering information that cannot be found any other way, information which will be our gift to humanity for all time. spike - --------------74585DC7DA00594FC8A87A54 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <I>Nathan Russell asked: How much are the people who are trying to</I> <BR><I>find a 10 million digit prime contributing to the search?</I> <P>Any machine that is running GIMPS is contributing to mapping <BR>the great universal math-space. If one is factoring, double checking, <BR>finding a slew of Mersenne composites (I know 30 now), searching <BR>for 10E7s, regardless, any way you look at it, you are on the team. <BR>If we use the orderly system George and Scott have created, we are <BR>uncovering information that cannot be found any other way, information <BR>which will be our gift to humanity for all time. spike</HTML> - --------------74585DC7DA00594FC8A87A54-- _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 2 Mar 2000 21:33:23 -0700 From: "Aaron Blosser" <[EMAIL PROTECTED]> Subject: RE: Mersenne: searching the biggies 2 >On the other hand, the existence of the EFF prize is a useful >tool in convincing companies to run GIMPS, for most IT >managers are quick to remind you that this *is* a business, >and it is here to make money. (Then you hope that same >IT manager hasnt the sophistication to calculate the actual >odds of bagging the $100K, realizing that the mathematical >expectation of the prize would not pay the extra electricity >use...) Actually, the cost of electricity isn't a factor for most large companies. I can only rely on my knowledge of the various places I've worked. We all know I worked at US WEST, and I can say that they leave their computers on all the time. The other big telco I just spent the last 1.5 years at also leaves their computers on 24x7, as does the company I work for now. The reasons for doing so are pretty simple: software deployment. When you want to push out a new version of Software Application version x.xx, you do it at night when the employees won't be affected by a reboot. So you tell people to leave their machines on, but just logout. Obviously, Wake-On-Lan is a great idea, but with legacy hardware, you either leave computers on all the time or you can't be as friendly with your software deployment. That's why I hope that some brilliant person will be able to go to US WEST and say "Hey, let's setup a Primenet Proxy, get these 30,000+ NT machines looking for primes, and do some good research". That person won't be me, by the way. Or maybe someone can go to a company like MCI WorldCom and say "Hey, let's get your 80,000+ NT machines looking for primes." Of course, I wasn't about to make that suggestion myself...what can I say? I'm a little skittish about such things. :-) Aaron _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 02 Mar 2000 23:42:13 EST From: "Nathan Russell" <[EMAIL PROTECTED]> Subject: Re: Mersenne: searching the biggies >From: Spike Jones <[EMAIL PROTECTED]> >Reply-To: [EMAIL PROTECTED] >To: [EMAIL PROTECTED] >Subject: Mersenne: searching the biggies >Date: Thu, 02 Mar 2000 19:49:36 -0800 > >Nathan Russell asked: How much are the people who are trying to >find a 10 million digit prime contributing to the search? > >Any machine that is running GIMPS is contributing to mapping >the great universal math-space. If one is factoring, double checking, >finding a slew of Mersenne composites (I know 30 now), searching >for 10E7s, regardless, any way you look at it, you are on the team. >If we use the orderly system George and Scott have created, we are >uncovering information that cannot be found any other way, information >which will be our gift to humanity for all time. spike I couldn't have said it better. That is precisely why I switched to GIMPS from another project whose sole purpose was to, at the cost of something like ten times our computing power for triple our expected time to next prime, simply recover a cute little, probably political, saying that someone had hidden. And, did I mention, provide PR for the large sponsoring corporation at the same time. Our work remaining is infinite, theirs might as well be. Two of their other projects lost GIMPS-years of work each because of stupid bugs and I got fed up and left. I will not identify my previous project; it's had enough press already because some find that its rather repetitive results further their political goals. I happen to agree with those goals, but I will no longer support the effort because it is, to be blunt, accomplishing nothing. This may seem like flamebait, and I do not intend it that way. If anyone wishes to disagree with me, on- or off-list, feel free to do so. Nathan ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 3 Mar 2000 17:42:02 +0800 From: "Dave Mullen" <[EMAIL PROTECTED]> Subject: Mersenne: Re: How much are the 10 M gamblers contributing? This is a multi-part message in MIME format. - ------=_NextPart_000_001C_01BF8537.C8F295E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Perhaps I'm a little under-speed here ... I understood that the $100,000 award was for the first 10 million digit = (that is to say 10 million decimal digit Mersenne Prime). Now a number of 10 million decimals is approx. 33 million bits long i.e. = the Prime Exponent would be approx. 33 million. And I'm sure some of you have read the theories about the "missing = Mersenne", and the analysis done on the sequence of known Mersenne = Primes. If they turn out to be accurate, then we might be better looking = at the 47 - 49 million Prime Exponent range. For interest, has anyone calculated benchmarks, or run LL tests in those = ranges; I guess not many, 8 months is a long time to wait for a result = !! Dave "And the winning ticket in this year's Christmas Raffle is number = 111111111111111111111111111......" - ------=_NextPart_000_001C_01BF8537.C8F295E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN"> <HTML> <HEAD> <META content=3Dtext/html;charset=3Diso-8859-1 = http-equiv=3DContent-Type> <META content=3D'"MSHTML 4.72.3110.7"' name=3DGENERATOR> </HEAD> <BODY bgColor=3D#ffffff> <DIV><FONT color=3D#000000 size=3D2>Perhaps I'm a little under-speed = here=20 ...</FONT></DIV> <DIV><FONT color=3D#000000 size=3D2></FONT> </DIV> <DIV><FONT color=3D#000000 size=3D2>I understood that the $100,000 award = was for the=20 first 10 million digit (that is to say 10 million <U>decimal</U> digit = Mersenne=20 Prime).</FONT></DIV> <DIV><FONT color=3D#000000 size=3D2></FONT> </DIV> <DIV><FONT color=3D#000000 size=3D2>Now a number of 10 million decimals = is approx.=20 33 million bits long i.e. the Prime Exponent would be approx. 33=20 million.</FONT></DIV> <DIV><FONT color=3D#000000 size=3D2></FONT> </DIV> <DIV><FONT size=3D2>And I'm sure some of you have read the theories = about the=20 "missing Mersenne", and the analysis done on the sequence of = known=20 Mersenne Primes. If they turn out to be accurate, then we might be = better=20 looking at the 47 - 49 million Prime Exponent range.</FONT></DIV> <DIV><FONT size=3D2></FONT> </DIV> <DIV><FONT color=3D#000000 size=3D2>For interest, has anyone calculated = benchmarks,=20 or run LL tests in those ranges; I guess not many, 8 months is a long = time to=20 wait for a result !!</FONT></DIV> <DIV><FONT color=3D#000000 size=3D2></FONT> </DIV> <DIV><FONT size=3D2>Dave</FONT></DIV> <DIV><FONT size=3D2></FONT> </DIV> <DIV><FONT size=3D2>"And the winning ticket in this year's = Christmas Raffle=20 is number = 111111111111111111111111111......"</FONT></DIV></BODY></HTML> - ------=_NextPart_000_001C_01BF8537.C8F295E0-- _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 3 Mar 2000 05:04:50 -0800 From: Paul Leyland <[EMAIL PROTECTED]> Subject: RE: Mersenne: searching the biggies 2 > -----Original Message----- > From: Spike Jones [mailto:[EMAIL PROTECTED]] > > On the other hand, the existence of the EFF prize is a useful > tool in convincing companies to run GIMPS, for most IT > managers are quick to remind you that this *is* a business, > and it is here to make money. (Then you hope that same That may be true for some businesses, certainly not all. Encouragement that is, not _not _ making money! I've won money from computational number theory, most recently from the 512-bit RSA factorization. All of my winnings are immediately donated to charity. Colleagues in other companies have a similar policy. Paul _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 03 Mar 2000 11:39:44 -0500 From: George Woltman <[EMAIL PROTECTED]> Subject: Re: Mersenne: searching the biggies Hi, At 11:42 PM 3/2/00 -0500, Nathan Russell wrote: >>Nathan Russell asked: How much are the people who are trying to >>find a 10 million digit prime contributing to the search? I agree that all machines are contributing to our knowledge of Mersenne numbers. The gaps will eventually be closed. Since you're a relative newbie, the overriding goal of GIMPS has always been "have fun". That translates into doing the type of work that most interests you (as long as we all do the work in a coordinated manner). >That is precisely why I switched to GIMPS from another project whose sole >purpose was to simply recover a cute little, probably political, saying >that someone had hidden. There are those that view prime number hunting as equally useless. I don't view GIMPS as in competition with other distributed projects. The links at http://www.mersenne.org let you choose the project that is most appealing to you. All are worthy in their own way. >Two of their other projects lost GIMPS-years of work each because of >stupid bugs and I got fed up and left. Uh... we had a bug too. Ironically, it was announced on April Fools Day last year. That caused quite a stir. We lost roughly a GIMPS month of work. >This may seem like flamebait, and I do not intend it that way. Welcome aboard and good luck with your LL tests - but most importantly... Have fun, George _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 03 Mar 2000 10:10:31 -0500 From: George Woltman <[EMAIL PROTECTED]> Subject: Mersenne: Benchmarks Hi all, Thanks to all that have submitted timings. There are still plenty of gaps to fill in and having multiple results for each machine is desirable. My first draft of the benchmark page is at http://www.mersenne.org/bench.htm Comments are of course welcome. Regards, George _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 03 Mar 2000 08:13:19 EST From: "Nathan Russell" <[EMAIL PROTECTED]> Subject: Re: Mersenne: Re: How much are the 10 M gamblers contributing? >From: "Dave Mullen" <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Subject: Mersenne: Re: How much are the 10 M gamblers contributing? >Date: Fri, 3 Mar 2000 17:42:02 +0800 > >Perhaps I'm a little under-speed here ... > >I understood that the $100,000 award was for the first 10 million digit >(that is to say 10 million decimal digit Mersenne Prime). Well, it doesn't have to be a Mersenne prime, but checking an arbitrary prime in a range in which probable primes haven't been shown (by elimination) to all prime inbvolves locating a strong candidate with probable primes and then trying all prime factors up to its square root. For a 10 million digit number, that would be all prime factors up to those of something like 5.1 M digits, which is to say a HUGE number of factors. Thus, the winner will almost certainly be a Mersenne prime, unless the Mersenne primes are shown to be finite in number, in which case we will have to wait until there are computers strong enough to factor arbitrary primes in that size range. I am not sure that factors such as the speed of light and the Hesieberg principal will even permit that in any reasonable length of time. > >Now a number of 10 million decimals is approx. 33 million bits long i.e. >the Prime Exponent would be approx. 33 million. > >And I'm sure some of you have read the theories about the "missing >Mersenne", and the analysis done on the sequence of known Mersenne Primes. >If they turn out to be accurate, then we might be better looking at the 47 >- 49 million Prime Exponent range. Well, that might be a good idea, but don't higher exponents take longer to test in a manner that is slightly more than linear? > >For interest, has anyone calculated benchmarks, or run LL tests in those >ranges; I guess not many, 8 months is a long time to wait for a result !! Benchmarks have probably been done, but last time I checked, nobody had turned in a completed LL test. There are also no people doing only factoring assignments in that range, that I recall (getting the list that far down takes a LONG time on my dialup connection, and here at school I have fairly limited time online). This seems to make sense, since the factoring people are (presumably often) intersted in immediate gratification rather than boosting their producer standing. > >Dave > >"And the winning ticket in this year's Christmas Raffle is number >111111111111111111111111111......" I wonder whether any of the newspapers will publish the entire decimal text of the next prime.... It'd be funny to watch people open the newspaper on the bus and see that :-) Nathan ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 3 Mar 2000 04:46:30 -0800 From: Paul Leyland <[EMAIL PROTECTED]> Subject: RE: Mersenne: Security and Prime95/mprime > linux is a Good Move ... ceratinly, in its default state, it's at > least as secure (when used as a firewall) as anything emanating from > a certain purveyor of operating systems based near Seattle. It's > cheaper, too! Please note: Seattle is about 5000 miles from where I am, despite my address, and I'm about fifteen times closer to Brian than I am to Bill. I also make absolutely no comment (I'm explicitly not allowed to speak for anyone but myself in a personal capacity) about the relative suitability of linux and any other operating systems for hosting a firewall. I will make one snide comment though --- Drawbridge ran very successfully on that paragon of security MS-DOS before it was ported to FreeBSD, where it now runs equally successfully 8-) > Hey, I'm a security guru of a sort ... the idea is not to run > anything which gives crackers a toehold, or causes unacceptable > throttling of the firewall throughput. Indeed. My advice is never to run anything on a firewall which you can't prove to your complete satisfaction is absolutely necessary. Given that a FW can be run on almost any old kit, you can hardly complain about hardware costs. I used to run the aforementioned Drawbridge and MSDOS on a 386sx-16 with 4M RAM, a 40M disk and two cheap ISA 3Com cards. It was easily capable of supporting a 10M ethernet with a couple of dozen machines behind it. It may sound like paranoia --- it *is* paranoia --- but by being paranoid you have a hope of resisting attacks no-one has yet thought of. > Few of us know what code George has embedded in the code which > computes the tag which PrimeNet uses to check that incoming results > are genuine. However, this does not seem to present a major risk! George is an honorable man, I'm sure, and has not knowingly put in any loopholes. I'm equally sure that he's not infallible and that he will freely admit to this. Do *you* want to bet the security of your site even more than you are now doing? > I've run mprime on an anonymous FTP server for almost 18 months & > haven't had any incidents (yet). The basic rules are (a) always run Ditto with NTprime. It really does seem to be a well-behaved program. Even so, it doesn't run on my firewalls. > All this is virtually paranoia since I believe the risk posed by > running mprime is practically nil - but it's good practise, anyway. Yup. Paranoia is a survival characteristic. Paul _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 03 Mar 2000 08:16:26 EST From: "Nathan Russell" <[EMAIL PROTECTED]> Subject: RE: Mersenne: searching the biggies 2 >From: "Aaron Blosser" <[EMAIL PROTECTED]> >To: "Mersenne@Base. Com" <[EMAIL PROTECTED]> >Subject: RE: Mersenne: searching the biggies 2 >Date: Thu, 2 Mar 2000 21:33:23 -0700 > > >On the other hand, the existence of the EFF prize is a useful > >tool in convincing companies to run GIMPS, for most IT > >managers are quick to remind you that this *is* a business, > >and it is here to make money. (Then you hope that same > >IT manager hasnt the sophistication to calculate the actual > >odds of bagging the $100K, realizing that the mathematical > >expectation of the prize would not pay the extra electricity > >use...) > >Actually, the cost of electricity isn't a factor for most large companies. > >I can only rely on my knowledge of the various places I've worked. We all >know I worked at US WEST, and I can say that they leave their computers on >all the time. > >The other big telco I just spent the last 1.5 years at also leaves their >computers on 24x7, as does the company I work for now. > >The reasons for doing so are pretty simple: software deployment. > >When you want to push out a new version of Software Application version >x.xx, you do it at night when the employees won't be affected by a reboot. >So you tell people to leave their machines on, but just logout. > >Obviously, Wake-On-Lan is a great idea, but with legacy hardware, you >either >leave computers on all the time or you can't be as friendly with your >software deployment. > >That's why I hope that some brilliant person will be able to go to US WEST >and say "Hey, let's setup a Primenet Proxy, get these 30,000+ NT machines >looking for primes, and do some good research". That person won't be me, >by >the way. Or maybe someone can go to a company like MCI WorldCom and say >"Hey, let's get your 80,000+ NT machines looking for primes." Of course, I >wasn't about to make that suggestion myself...what can I say? I'm a little >skittish about such things. :-) > >Aaron Last time I checked, there were two universtites (labeled as such that is) at the top of the list but no companies really near the top. Nathan ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 3 Mar 2000 19:35:51 -0000 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: Re: Mersenne: Re: How much are the 10 M gamblers contributing? On 3 Mar 00, at 17:42, Dave Mullen wrote: > Now a number of 10 million decimals is approx. 33 million bits long i.e. > the Prime Exponent would be approx. 33 million. Yes, this is perfectly true. > > And I'm sure some of you have read the theories about the "missing > Mersenne", and the analysis done on the sequence of known Mersenne Primes. > If they turn out to be accurate, then we might be better looking at the 47 > - 49 million Prime Exponent range. Ah, but ... theories being theories ... Suppose you have an object whose colour is such that it appears red until 4th March 2000 but blue from that date onwards. So far, every time you've observed it, it's proved to be red. Past observations are not neccessarily a good predictor of what you will observe tomorrow! No-one seems to seriously doubt that the underlying distribution of Mersenne primes is at least fairly random, and that the density falls off with increasing exponents. So the chance of any particular exponent in the region of 48 million yielding a Mersenne prime is less than the chance of any particular exponent "just big enough" for the Mersenne number to have 10 million digits. To test an exponent around 48 million will take about twice as long; so (given the current state of the art) it looks as though testing the smallest eligible exponents is the better strategy. If you really want to have a go at the 48 million range, fair enough - but please tell someone (George?) so that nobody else wastes time by duplicating work on the same exponents - there are plenty of candidates available!!! > > For interest, has anyone calculated benchmarks, or run LL tests in those > ranges; I guess not many, 8 months is a long time to wait for a result !! The existing v19 program is quite capable of running 10 timed iterations on an arbitary exponent up to at least 79 million. Extrapolation of the full test run time is a simple job, in fact "Advanced/Time" does it for you. No-one has reported any completed LL tests for any "10 million digit" exponent yet; v19 hasn't been out that long, so that even anyone who started on Release Day & has religiously followed the processor speed leapfrog game is probably still some way from completing the first one. > > "And the winning ticket in this year's Christmas Raffle is number > 111111111111111111111111111......" How many 1's? Regards Brian Beesley _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Fri, 03 Mar 2000 15:10:45 EST From: "Nathan Russell" <[EMAIL PROTECTED]> Subject: Re: Mersenne: searching the biggies >From: George Woltman <[EMAIL PROTECTED]> >To: "Nathan Russell" <[EMAIL PROTECTED]>,[EMAIL PROTECTED] >Subject: Re: Mersenne: searching the biggies >Date: Fri, 03 Mar 2000 11:39:44 -0500 > >Hi, > >At 11:42 PM 3/2/00 -0500, Nathan Russell wrote: >>>Nathan Russell asked: How much are the people who are trying to >>>find a 10 million digit prime contributing to the search? > >I agree that all machines are contributing to our knowledge of Mersenne >numbers. The gaps will eventually be closed. > >Since you're a relative newbie, the overriding goal of GIMPS has always >been "have fun". That translates into doing the type of work that most >interests you (as long as we all do the work in a coordinated manner). I feel that I appreciate the excitement of doing the first-time tests, and that is why I am chosing to do those. I don't honestly think I would have the patience to run 10 M tests, and if I were in it for the money (which I'm not) I would calculate that the regular tests actually have a higher expected prize yield per time. I actually just got 2 weeks' worth of factoring for myself, just for variety's sake. > >>That is precisely why I switched to GIMPS from another project whose sole >>purpose was to simply recover a cute little, probably political, saying >>that someone had hidden. > >There are those that view prime number hunting as equally useless. I don't >view GIMPS as in competition with other distributed projects. The links at >http://www.mersenne.org let you choose the project that is most appealing >to you. All are worthy in their own way. > That is true. I was stating my own views, and I respect that others may have different motives. >>Two of their other projects lost GIMPS-years of work each because of >>stupid bugs and I got fed up and left. > >Uh... we had a bug too. Ironically, it was announced on April Fools Day >last year. That caused quite a stir. We lost roughly a GIMPS month of >work. I am aware that there was a bug in V 17. There will always be bugs. The bugs (plural) that occured in my former project were merely the final reason that I decided to leave. Nathan > >>This may seem like flamebait, and I do not intend it that way. > >Welcome aboard and good luck with your LL tests - but most importantly... > >Have fun, >George > ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com _________________________________________________________________ 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 #701 ******************************
