Re: Mersenne: servers down completely?
Seems to be up now everyone... I was watching this through most of the day. I'm on GMT and it was still down at about 17:30 today, so off the top of my head this was down for at least 36 hours from when the first mail in this thread was sent! Surely there must be better ISPs in California than that? :-) Robin Stevens wrote: On Sun, Mar 23, 2003 at 10:11:08AM -0800, John R Pierce wrote: I can't even raise the mersenne website. getting errors on entropia.com/ips too, yet entropia.com's home page comes up fine. traceroute shows a nice loop: -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Communication between GIMPS Forum and Mersenne mailinglist (was: Poaching -- Discouragement thereof)
If this is happening big time then the list is finished, and is basically an announcement-only list. I'm sure many people like the fact that mailing list messages come to them, rather than them having to make time to go and browse a website and deduce the updates from remembering when they last visited. The correct way to do discussion lists has never really been mail or web, but news (NNTP). This way everything stays under its own thread, and no-one has to download the whole page of forum discussions to get the one extra message at the bottom. An idea, but I suspect no-one would move. Also, when the forum was first announced, it was never actually decided what would happen with regard to "copyright" on the messages. The discussion trailed off with some people saying that they wouldn't post to a forum which claimed copyright, but no-one ever stated that the forum wouldn't do just that. Perhaps there can be some belated clarification on this? Also, what do we do about archiving material (simple for a list)? If the forum goes down is that the end of all the postings? Richard Woods wrote: What should/can be done to ensure that those who can't/don't read the Forum are alerted to, and can contribute to, important topics discussd on the GIMPS Forum and are informed of important announcements/decisions posted on the Forum? [Sent this earlier but it didn't get through... Sending again] -- === Gareth Randall === -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: P-1 and non k-smooth factors
Isn't this (3GB user mode) only supported on Windows NT Advanced Server? (which is probably free for you to use but for everyone else costs the same as a new car!) If it isn't then I've encountered some people who will wish they'd have known about this a long time ago :-) Paul Leyland wrote: From: Brian J. Beesley [mailto:[EMAIL PROTECTED]] usable by a single process is limited to 2 GBytes. (There is a "big memory" variant of the linux kernel which expands this to 3 GBytes, but the point still stands). FWIW, WinNT and its descendents can be booted with /3gb in boot.ini, whereupon a single process may use up to 3G of physical memory. This switch tends to be used mainly on big SQL server boxes but I found it necessary when running very large filtering and linear algebra jobs for NFS factorizations. For this I needed a very large chunk (>1Gb) of *contiguous* virtual memory and although the standard boot mode would let me have up to 2G of VM, system DLLs were loaded somewhere near the 1G region, thereby fragmenting memory. Booting with /3gb placed the OS well out of the way and let me have the space I needed. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Linux kernels
I've seen a kernel config option to allow a 3GB-user / 1GB-kernel split, even on normal hardware, so you should definitely be able to reach 3GB on any CPU type. As for the 36-bit address extension, I haven't tried it but the following .config entries look relevant: # CONFIG_HIGHMEM4G is not set # CONFIG_HIGHMEM64G is not set Chris Marble wrote: Steinar H. Gunderson wrote: Actually, in newer Linux kernels (ie. at least all 2.4.x versions that I can remember) you can expand this further, up to 64GB on CPUs that support it (which is, AFAIK, Pentium Pro and newer, so in reality it won't be a problem). I don't really know what it does, but judging from the help entry, it appears like it can still only address 4GB at a time, so it's more or less Actually it's a lie. I've got a dual Pent III with 4Gb RAM. You cannot have a single process that uses more than 2Gb of RAM with any of the Linux 2.4 kernels. We hadda install Solaris on the box to do what we wanted to. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Update on my stability issues
Hi, It's probably worth saying this for the benefit of all readers who may be experiencing heat issues with their systems: The front air intake vents on almost every PC case I have ever seen have been virtually *useless*. For some reason manufacturers continue to drill a few pathetically small holes in the steel sheet and call that an air duct. People then put case fans against these and try to suck against what is 90% metal sheet and wonder why not much happens. What you should do is to take a saw or a drill and cut the whole circular section out! You may end up with sharp edges, and you need to take precautions against metal shavings. You may also need to drill some neat holes (e.g. 10mm diameter) in the plastic front bezel in order to provide an unimpeded air path. Nevertheless, when the procedure is done you should be able to hold a match in front of a machine with nothing other than the PSU fan and see the flame visibly sucked into the case. If your airflow can't do that, then any internal fans you deploy are going to be pulling on a vacuum (or rather, reduced pressure). If it can do that, then you are in a *much* better position to keep your number cruncher cool and reliable! Nathan Russell wrote: I'll delete all my selftestNpassed lines, just to be on the safe side, but I really think the issue was a heat issue, which is now gone. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Ernst Mayer's GIMPS pages
You probably were about to do this, but... Add a line like this to the BIND zone file. (I see you're the SOA contact in the "hogranch.com" DNS zone, so should have access to this.) @ IN A 204.182.56.143 This is like: www IN A 204.182.56.143 Zone file is probably /etc/named/db.hogranch.com Then you'll have an address record for "hogranch.com" as well as "www.hogranch.com" and all existing links will work. John R Pierce wrote: >How many times did you try, and over how long a period? >Last I heard, Ernst Mayer lived near San Jose, CA, and kept the >web pages on a home machine. One headline at www.sjmercury.com reads actually, he's using MY server which is at my home in Santa Cruz, and in fact our power was out for about 3 hours today... my server's UPS died after 1 hours. all back up now. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Modularising Prime95/mprime - a path to broader development.
Dear Brian, Could you please expand upon how this secure certificate concept would work, for the benefit of myself and the list? Unless there is more to it than I currently comprehend, this only authenticates results as coming from specific users, rather than authenticating that the result is correct and genuine. For instance, how can a new user who has had no previous contact with GIMPS prove that they have completed a Lucas-Lehmer test correctly? (Naturally, the GIMPS secret algorithm would always be vulnerable to reverse-engineering. I am aware that modularising Prime95/mprime would not change this risk.) Brian J. Beesley wrote: >I realise that the code >for generating verification codes must remain restricted, No - there is an alternative, which is for results submitted to be accompanied by a secure certificate generated by the server. >because that is >the only authentication that work has really been done and done correctly. There are a couple of points here: (1) the verification code may be crackable; (2) there may be ways of persuading the program to submit results without actually executing all the iterations required. If every user had a (free) secure certificate, all results submitted would be traceable to the individual user. This scheme would also make it possible for other clients to use the automatic server interface, instead of having to rely on the manual forms (& not getting PrimeNet credit for work completed). -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Dissed again
Yeah, I noticed that one of their "top 100" users has an average work unit time of less than 30 minutes. Compare that to the ~22 hours I'm getting for a PII 450Mhz, and the SGI team's average of over 6 hours even though they're running on just about the most powerful (and sadly, most expensive and least common) floating point architecture going, 64-bit MIPS. What the hell is this guy pretending to be running? I hope they're disregarding the results of his workunits (almost certainly not.) False data like this would represent dark patches in the sky wherever duplicate work units to this user overlap. Fortunately for SETI that's not terribly bad. For GIMPS it could mean loss of data that would never be found again for decades. Richard Woods wrote: Let's not be _too_ eager to emulate SETI@home's popularity and user-friendliness -- http://www.zdnet.com.au/newstech/security/story/0,224985,20269509,00 .htm "Cheats wreak havoc on SETI@home: participants" "SETI@home administrators are allegedly ignoring claims that the project is being sabotaged by miscreants who are threatening to derail its reputation and that of many valuable Internet-based distributed computing projects." Richard Woods -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Modularising Prime95/mprime - a path to broader development.
Dear All, I'd like to suggest that prime95/mprime be "modularised", and that only the core calculation component be kept closed source. I realise that the code for generating verification codes must remain restricted, because that is the only authentication that work has really been done and done correctly. However, I do not see any reason why any of the building blocks other than the core calculation component actually need to be restricted. I also see many benefits of them being made open to contribution. The following units could be made into separate modules, be they executables, scripts or linked libraries: 1. Work selection algorithm 2. Results logging and reporting 3. GIMPS server communications 4. Graphical progress animations 5. User account management 6. Numeric computation module (the actual factoring and LL part) 7. Overall control module Each of these would have ways of communicating with the others, such as pipes, IPC or files, but these could of course be freely customised where desired. The computation module would be simplified, and be told exactly what work to do. The key benefits are: 1. Removal of many bottlenecks caused by the understandibly limited time of core developers. 2. Substantially easier bug-fixing. (What's error 2250 again? Quick search of the source for the server comms module. Oh yes, that means...) 3. Vastly increased potential for user participation and development. Prime95/mprime could be regenerated as a collection of programs, such as: On Windows: One executable and multiple DLLs or: Multiple executables, and one calculation component in Win32 command-line mode. On UNIX: Separate binaries and scripts. One script to start the collection running. Wouldn't it be great if from some point in the near future, "feature request" posts to this newsgroup became more like "I've written a fancy improved frontend to GIMPS with some cool graphics, see this link for more info", rather than "It would be nice if you could incorporate a better frontend with some cool graphics." :-) Further, the ability for users to run their own personalised frontends might give GIMPS the tangible advantage over other distributed projects that many readers would so like to find. Yours, -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Dissed again
This amazing number of participants may be misleading. For instance, I've been running a SETI@home client ... (okay, okay, it's because SETI supports uncommon platforms) and was quite amazed, when I returned my first completed workunit, to find that I was now ahead of over 30% of their users. After returning 2 work units I think I was ahead of 50% of them. Recalling that the total userbase of SETI was then almost 4 million users, you can see just how many lamers SETI must have listed! (Note: these workunits take about 22 hours on a PII-450, so this isn't much effort) Perhaps we could catch some more publicity by appending "@home" to the end of the project, thus: "GIMPS@home", or "primes@home" ? Jeff Woods wrote: At 09:09 AM 10/22/02 -0600, you wrote: > Folding@Home's success: > http://www.sciencedaily.com/releases/2002/10/021022070813.htm > > Again, they mention SETI@home. As if that were the only other > distributed project out there. *sigh* Two years ago, Pande launched Folding@home a distributed computing project that so far has enlisted the aid of more than 200,000 PC owners, whose screensavers are dedicated to simulating the protein-folding process. Either they were really great activists in signing people up, or GIMPS has SOMETHING about it that won't get people to participate. We either need to step up our profile, be more active at recruiting, or do SOMETHING to get us off the static bubble we've been on, at about 18,000 members, 31,000 computers, and falling. Our output goes up ONLY because most of our members upgrade as CPUs get better and cheaper. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Error rates
This would presumably give rise to a serious problem in which people could simply claim to have done work which failed, and turn up at the server and ask for credit to their user scores. There wouldn't be a reliable way (based on current mechanisms) to cross-check the validity of their claim if the results are incorrect and can't be verified by another user. Jeff Woods wrote: > And if the answer to the above is "yes", then why can't Prime95 be coded > to simply "credit" partial time, and throw the number back in favor of a > smaller exponent, a double-check, or factoring work, instead of > permitting work to continue for another few weeks (or months) that is > likely fruitless? Yours, -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: GIMPS forums!
Some general questions regarding the ongoing provision of information on the aforementioned forum: 1. What happens to the archive of posts if "teamprimerib.com" suddenly disappears? Is it lost forever? 2. Are these messages really going to be archived anyway? Will messages expire beyond a certain age? 3. Also, although less significantly, does the hosting site automatically gain ownership of all the material posted? Some sites seem to think they do, although I haven't checked this one. Certainly an archived and freely available mailing list would be a safer bet for all three of the above. However, I'm not against original and accessible ways to make information accessible, of course, so don't take this as a flame against the forum :-) George Woltman wrote: > Hello all, > > Thanks to the dedication of a GIMPS member, we now have our very own > bulletin board system. Check it out at http://www.teamprimerib.com/gimps/ > > The forums are empty now, but you can be among the first to start up a new > thread. Sign up and introduce yourself, then we'll see what this grows > into! > > I know some folks prefer the mailing list approach for news. I'll continue > to post news on this mailing list and on the forums. The forums will let > us do searches and see past posts easily. > > Have fun, > George > > P.S. Don't be fooled by the "www.teamprimerib.com" in the URL. The forums > are for all GIMPS members and will not be used as promotional tool for this > particular GIMPS team. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Case against running prime95 as an NT service with a GUI.
A short time ago there was a discussion relating to the prime95 process running as System on NT/2000, and the subject of security issues relating to it being accessible from a normal user's desktop came up. The article linked below describes a serious security issue caused by this scenario, in which such applications can be exploited to give total system compromise. http://www.theregister.co.uk/content/4/26561.html Yours, -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: W2K service installation problems
Hi, I'm no expert on windows programming, but take a generally downbeat view of the amount of ongoing time and effort required to code for the "proprietary API of the week" that seems to characterise this OS. Consequently, is it possible for someone to code a service "wrapper" that spawns the prime service as an additional process? In other words, separate out the service management and icon code into a separate process, which can be developed by a larger public group, rather than have all this code in prime.exe itself with the corresponding requirement that the coding effort all fall on the shoulders of one person. This would allow outside parties to develop the most fancy and functional frontends, and be able to do all the compilation steps themselves while circumventing the need to have access to the necessarily secret encryption algorithm that protects the authenticity of results. Can this be done? Surely this one's a runner? Yours, Gareth George Woltman wrote: > At 10:46 AM 7/29/2002 -0700, Aaron wrote: > >> I suppose it's probably documented somewhere, but it seems that Prime95 >> ignores any service name settings in the existing NTPrime local.ini >> file... >> >> So I'm still using NTPrime on my dual CPU machines... Any chance of >> getting prime95 to honor the service name settings in the local.ini file >> just like ntprime did? > > > Already coded and tested. Look for the fix next time I upload a new > prime95 -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Old 486 retired...
An impressive record! Probably worth taking a photo of it. Well, the world's first web server, a NeXT computer, is in a display cabinet in a restaurant in CERN. Maybe one day there'll be a "hall of fame" (online even) for veteran GIMPS systems :-) Johan Winge wrote: > I see that the number of Intel 486 now has decreased to under one hundred, > and today one the number decreased further as I retired my trusty "old486". > This machine joined GIMPS early in 1999 and has trial factored eleven > mersenne prime candidates since then. Only one factor was found: on May 14, > 2000 it reported that M11941547 has 9833383992510866143 as a factor. Well, > now it has worked enough. In its place I have added a shiny new 2 GHz > Pentium 4. Quite a change I may say... > > Cheers! > -- Johan Winge Yours, -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Instructions for how to compile mprime from source?
Hi, I've just downloaded the mprime source in order to attempt compilation on Solaris 8 x86, which I know does work (from Tom Wu some months ago). However, neither source21.zip nor source22.zip contain any instructions on what to actually do! No readme, no master makefile. I can't find any documentation online. I have compiled many apps over the years. Am I missing something obvious? Can anyone post a quick set of commands to compile the binary? Perhaps instructions can also be posted on the source file download page. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: electrical energy needed to run a LL-Test?
For Linux users wondering how to control the monitor auto suspend or auto power down, try: xset dpms force standby or xset dpms force suspend (See man page or --help for xset for more information and options.) If you set this as a keyboard shortcut you can actually go into power saving mode instantly, which I haven't seen on windows (although I'm not up to date on the windows front!) As this is an X thing, I suspect it will work on other OSs as well as Linux. I started using an old system of mine to heat an outbuilding, while running a prime program. I thought that rather than power an electric fire, I might as well get some work done for that electrical energy! Robin Stevens wrote: > Better still, switch the monitor off when you're not using it :-) I'm > amazed at work at how many monitors seem to be on permanently, not even > entering power-saving mode. What a waste - at least a CPU can do something > more useful than providing visual entertainment for the spiders. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Re: Mersenne Digest V1 #950
Yes, there seem to be a lot of journos around who just surf the web all day, and thus obtain the entire material for their stories. Look out for "...according to a report on the company's website..." :-) So do we need a overview of the GIMPS project on mersenne.org (perhaps even linked to as "notes for journalists") which gives the core facts so that people don't keep getting it wrong? Bruce Leenstra wrote: > Gordon writes: >>Now where on Earth does the figure of 210,000 computers come from?? > > > This is the same mistake made on a previous news item: Both of them are misquoting >an earlier study that determined a *Total* of 210,000 computers worldwide were >participating in a distributed computing project of some kind. The other item was >worse: it used the 210k to calculate ratios and percentages to compare the different >projects. So of course all the numbers were useless, and the conclusions were idiotic. > > Bruce Yours, -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Aside: Who's got the most photogenic prime machine?
Hi, Many of us must have watched the latest movie and thought that it would be just us/more interesting if they had instead made a documentary on the computer technology that rendered the graphics. Although we have the stats on the number of machines participating in GIMPS, do any of us have any pictures? I wondered if anyone has any photos of interesting machines or machines in strange places running GIMPS. Perhaps a website could be created with links to some "readers pictures" :-) Perhaps with some pictures of the owners thrown in? (I've got a Linux box in my kitchen, but it's not very picturesque. Someone here must be able to beat that :-) Yours, -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: A runaway P95 install script?
...Almost want a "three strikes and you're out" :-) Seriously, though, if this is a widespread problem then we should consider some sort of web-based form or automated e-mail confirmation system where the user basically says "Yes, I'm about to request a stack of exponents and I am serious - this is not a download script gone wrong." I related idea is: first-time users could be allowed to reserve one or two exponents, then the more completed results they return the more allocation they get. Okay this doesn't directly address the problem of a rogue machine in a trusted team, unless you limited by machine too, but I thought I'd mention it as any redesign of the allocation system to address poaching could incorporate such things. I'm not being too sepcific because I know that if this has value then other people will draw the complete picture. Henk Stokhorst wrote: > Nope, it is the very same machine of the very same team that did this > twice before, again in the same characteristical amount of reservations > per hour. Not a single exponent will be returned. The only way to > contact that machine seems to be through the emailaddress in the client > if even that is known to the server. > > YotN, > > Henk Stokhorst -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Re: Are problems more likely in the last 1% of a 10,gigadigit LL?
(Although this is a good idea...) I think we should specifically AVOID adding substantial new functionality to the prime95/mprime program itself. Instead, where possible, this new functionality should be implemented by separate programs. My reasons are: 1. Avoids code bloat for one particular app, thus increasing reliability. 2. Avoids piling all the work onto one programmer. This seems to have become rate limiting already in some areas. 3. Minimises the ability of bugs in non-important sections to bust the results of the important sections. (similar to point 1) Aaron Blosser wrote: [snip] > I doubt George would be interested in working in a little simple zip > routine when saving/reading save files? It might slow it down too much > for some folks (although honestly, it takes a fraction of a second to > zip using the lowest compression level), but maybe a nice option for > those looking to save a bit of space when testing large exponents. > Especially if you save interim files or have 2 saved files... the space > savings would add up quickly. > > Aaron [snip] Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: List librarian?
Dear All, I am often impressed by the amount of detail with which some posters to this list describe technical details and trouble-shooting procedures. In fact, it seems a shame that only a few interested parties get to read them at a time, before they disappear. Okay, so there are probably searchable archives out there but are they really in a useable indexed form? In view of this situation: Does anyone have any ideas for: 1. Having a "librarian" to create a "real FAQ" - not just the questions people are expected to ask but the ones they really do. 2. "Open sourcing" collected material so that if one site goes down forever etc someone else can repost the entire volume. 3. Creating a system whereby multiple people can maintain an FAQ volume to avoid overloading a single person. Okay, this suggestion isn't strictly on topic, but I believe that: 1. The documentation relating to GIMPS could do with improving. 2. The people who know most about it are too busy working on the algorithms to write documentation! 3. The collected trouble-shooting tips on this list (perhaps anonymised) would be ideal. Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: mprime unnecessarily requires default route.
Hi, Just wanted someone to verify that this isn't deliberate behaviour before submitting it as a bug (maybe I just have): Using mprime 21b on Linux: 1. On client machine, I specify a remote HTTP proxy in the correct config file. The proxy is on my local subnet. 2. I get "You are not connected to the Internet. Will try again" 3. If I then add a *default* route on the client, communication works fine via the proxy. So. the test order should be changed to: 1. If using proxy, is that reachable? If not, give error. 2. Else, is primenet server reachable? If not, give error. but at the moment it appears to be: 1. If default route not present, give error. Presumably most users with several machines will have encountered this? Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Prime freezing when connecting by DSL to Primenet
I wonder whether this is caused by Firewalling software or automatic virus detection software. Has this avenue been investigated? Some of this software might have the power to block network connections or basically suspend the program trying to make them until such time as Wild guesses: 1. Is the server actually closing its connection to the client (and vice versa)? I seem to remember seeing an active connection listed in netstat even thought the communication had finished and I'd dropped the dial-up connection. If the firewall software was trying to do some sort of content verification or other checking, might it be waiting for the connection to close? 2. Is something trying to do a reverse DNS lookup on the server before it allows it and failing? Does the server have a reverse DNS entry? (I've just checked and it doesn't.) 3. The fact that the HTTP request asks for an ".exe" (/cgi-bin/pnHttp.exe) might cause some sort of virus checker to kick in and insist on interfering with the reply. 4. Is the server somehow being blocked? If there's some sort of URL/content checker interposed in the connection, is it classing the server as an "unknown" group (we assume we're not in the "sex and violence" category :-) and trying to filter it or something? It seems to me that if the connection never closes, and there's virus/content checking in place, then there might be an explanation for a very long wait. Perhaps I've been able to offer some clues. Yours, Gareth Randall Steve Harris wrote: > Interesting... I have had that happen to me as well a few times with PCs > on a DSL (but without AOL). It doesn't happen on a regular basis but > does lock up the program (v21.3) for hours or days at a time. Just > caught one today that had been stuck like that for seven hours, even > 'end task' couldn't stop it. I had to reboot the PC, then it connected > and reported in just fine immediately afterwards. > > > > Irv, I know this is no help, except to let you know you aren't the only > one... > > > > Steve Harris > > > > *-Original Message-* > *From: *[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> <[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> > *Date: *Friday, January 11, 2002 10:58 PM > *Subject: *Mersenne: Prime freezing when connecting by DSL to Primenet > > I am running version 21.4 of Prime. I recently started using a DSL > connection on AOL. ( I am using Version 7.0 of AOL). Since I > started using this arrangement, Prime locks up whenever it connects > with Primenet. After some delay, during which time everything > stops, Primenet reports an ERROR 12031. The only way that I can > successfully report to Primenet, is to connect to AOL using my modem. > > This problem occurs when reporting results, getting new exponents > and reporting expected completion dates. > > Any suggestions? I can give more details if needed. > > Irv Rosenfeld > -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: M#39 news!
Nathan Russell wrote: > So someone managed to find, or mis-find, the exponent, possibly by > speaking with Entropia. I wonder how much of a blow this is to the > chance of GIMPS' getting a mention in other newspapers/sites. Shame it's such an amateur article too. Almost anyone on this list could have written a more exciting, more interest-evoking article than that. There's a vague reference to the science whenever there's a "gee whizz" to be had, but basically the feel of an outsider without much knowledge or interest who just wants to get that "headline" out and who cares if it screws up anyone else. I would have expected a lot better from Academic Press than that. Perhaps someone here should write a better one for publication on the GIMPS website? (I can't as I'm on business for the next week, and by then it'll presumably be old news.) Yours, -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Trial factoring time
Funny you should mention that... I just switched from running mprime on my 400MHz K6-2, to running it on my 450MHz PII. I'd previously been running Tony Forbes' MFAC on the PII instead, but this fits mostly within level-1 cache and hence made no use of the larger PII cache or the better FPU. The result? Mprime cycle times down from 0.465 to 0.197sec, and I've been running this inefficient set-up for more than 8 months! Damn... Of course, as you asked, Tony Forbes' MM61 mersenne project is at: http://www.ltkz.demon.co.uk/ar2/mm61.htm Yours, Gareth Randall George Woltman wrote: > At 12:05 AM 11/28/2001 +0100, george de fockert wrote: > >> My factoring machine speed is k6 400Mhz , and I know of the benchmark >> pages, >> but there are no factoring benchmarks, only LL. >> So, forget trial factoring for the next months, and do only LL ? > > > The K6 (as well as Cyrix and Intel 486) chips have lousy floating point > units. > So bad in fact that a 400 MHZ K6 is about 3 times slower than a 400 MHz > PII when it comes to LL testing, ECM, and P-1 factoring. > > What you need is a project that uses integer arithmetic - like > distributed.net. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: energy consumption Prime95 on 130 computers
Henk Stokhorst wrote: > Tijl Kindt wrote: > >> * Does anybody know how much more energy would be consumed by running >> Prime95 10 hours a day and on all workdays on 130 computers*> >> > Depends on, if the systems are on anyway, there will be no noticeable > difference. If they are switched on just to run prime95, whilst they > would otherwise be off, it is simply the Watts written on the back of > the computer times the amount of hours the computer is on. The extra power is certainly noticeable on its own, but perhaps less noticeable compared to the consumption of the rest of the systems and monitors etc. If we say that a highly active CPU and memory subsystem running prime95 takes an extra 20 watts, then that's an extra 20Wx130 = 2.6kW! This is enough to heat a fair-sized room! To my knowledge the power rating given on the PSU is actually significantly higher than that actually consumed, since this is a maximum. In fact a system power consumption of half what it written on the back is more normal unless there are a lot of internal devices. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Primenet communication details.
[EMAIL PROTECTED] wrote: > On 20 Nov 2001, at 23:46, Martijn Kruithof wrote: >>Are you talking about a linux system?! Of course! >>Add a cron job executing: >> >>ifup ppp0 (or your distro's equivalent to get up the dail up link) >>sleep 10 ; mprime -c ; sleep 5 ; ifdown ppp0 >> >>Every week for instance (also configure mprime accordingly) >>Configure mprime to not contact priment automatically. >> > > ... but isn't there an option for autodial - in linux as well as > windoze? You probably mean "diald", although manual dialling seems best for home use to me. > Personally I don't use it because I've had trouble with autodialled > connections not dropping - and I'm on a pay-by-time connection :( They also don't know when not to drop - sometimes in the middle of doing something. Again, seems best for unattended machines. > BTW if you use the above script you should set your "days > between sending new end dates" to _6_ rather than 7. The reason > is that mprime -c will do nothing unless prime.spl exists, and > prime.spl will not be created until the next multiple of 65536 > iterations following N days since the last PrimeNet checkin. This is all good information. Thanks. To conclude then, I presume the "-c" method is the current "accepted" way of doing it. However, my suggestion of being able to run an arbitrary program has obviously now been heard by those who matter, so we can now wait to see whether such a feature appears in the next version/release. -- === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Primenet communication details.
Hi, Could someone just confirm to me the server or DNS name that is contacted by the mprime client in order to transfer information. I understand this uses the HTTP protocol on port 80. Is this correct? I plan to relocate my mprime to a more powerful system. However, this system won't be dialled up directly and it would be good if this system could request a dial-up when it requires it. Thus the following idea: Have an option that mprime can run a program of the user's choice when it wants to make a network connection for any reason, and perhaps another when it has finished. As both of these are noted in the "-d" output, this should be very simple to code in. Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Re: SMT
George Woltman wrote: > I agree with Steinar's intriguing observation. Intel's SMT looks > like two CPUs to the operating system but the two CPUs share > one core. Oh no, they're not going to cobble something together like that are they? This looks like another forthcoming disaster where the chance to make a real technological leap is squandered in the name of "compatibility" with some OS that firstly didn't deserve such an effort, and secondly could have been patched anyway. I hope they leave a mechanism for proper OSs to take full control and assign the parallel threads themselves, otherwise this will be another PC architectural compromise that blights performance or otherwise adds timewasting complexity like say: register sharing for MMX and FPU, cascaded IRQs, FPU IRQ, polled gameport, the whole of real mode(!), shite DMA, that "pretend the boot CD is actually a floppy disk" crap, and many others. The idea of SMT is to be able to feed all execution pipelines simultaneously, by allowing instructions to be drawn from several threads. So for example, when an application has nothing but integer instructions to execute, then floating-point instructions can be drawn from a process waiting to execute these and fed down the then idle floating point pipelines. For computational applications this is significantly different from having two processors. Prime95/mprime should be saved by accident rather than design - It executes mostly floating point, so will not compete head-on with "ordinary" apps which are mostly or entirely integer. The following article explained SMT (on the proposed Alpha EV8) for me: http://www.realworldtech.com/page.cfm?ArticleID=RWT1226 Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: mprime for Solaris x86 ?
George Woltman wrote: > Just grab the source at http://www.mersenne.org/source.htm and see if it > compiles and links. You will not compile the ASM stuff - both ELF and COFF > style object files are provided for the ASM code. Er, my Solaris x86 machine just expired (suspect failed PSU), so maybe someone else can try this! :-( -- === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: SMT
George Woltman wrote: > SMT for those that don't know makes one P4 CPU look like 2 CPUs > to the operating system. Each "virtual CPU" has its own set of registers > and each runs a different program (actually a different "thread"). The real > CPU can now execute instructions from either virtual CPU. SMT on Intel? I didn't know about that. If SMT is implemented like the planned Alpha EV8 implementation, then it will be up to the OS to schedule multiple tasks for the processor. Consequently unless the OS had special interfaces to allow one program to consume several SMT slots, the program would either be restricted to running as normal, or have to try running as several processes, or would have to replicate the necessary OS kernel functionality itself (difficult, and not portable). I think the odds are that prime95 / mprime would not be able to gain much unless either the OS makes special arrangements for single compute-intensive programs, which seems unlikely since SMT is intended for CPUs running multiple processes, or the OS is open source and can be patched at kernel level, which excludes windows. Some SMT news that I know of: Alpha EV8 will have SMT with 4 simultaneous execution paths. Alpha recently got canned by compaq, so the above may never happen. Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: mprime for Solaris x86 ?
Dear All, I have to do some work with Solaris 8 on x86 (i.e. Intel processors), and was wondering if anyone felt inclined to port mprime to this OS. Now I know that most ports actually take a long time and are not worth it unless there's a significant target user base, but I'm not suggesting the typical "Can I have this graphics-intensive Direct-X Windows game on my Mac running Linux?" :-) Mprime is simply a command-line program that does file I/O, outgoing network connections ... and that's about it in terms of interacting with the OS. All this is standard POSIX stuff which might even compile without change (he says). Consequently the only questionable part is whether the assembly code is sufficiently OS independent. Would anyone be interested in giving this a try? Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Re: Mersenne Digest V1 #895
It's actually a Microsoft program and is one of their "kernel toys" package. http://www.microsoft.com/windows95/downloads/contents/wutoys/w95kerneltoy/ I'll answer to the group as well since this is a very useful tool for prime95 users. It allows you to spot processes that go into busy waits and the like which waste CPU time. Try holding the mouse button down on the desktop - went to 100% CPU on my Win95 system, but I haven't used that in over a year now! [EMAIL PROTECTED] wrote: > > Hi group > > This question was asked before but I lost the info. What is the website to obtain a >copy of WINTOP, the memory usage program. Also, what is the site for the archives >of this list. > > Please answer this directly to me. > > Thanks > Irv Rosenfeld -- === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Entropy of mersenne calculations.
What is the entropic efficiency of our calculations? Is it possible to say how much "work" must be performed in order to verify whether a number is prime? If it is, then how efficient are our methods in comparison? For instance, can it be shown that there is theoretically a better method, but one that no-one has discovered? -- === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Utilities for "headless" computing.
Greetings, Intro = People running computational projects such as GIMPS normally end up running "headless" computers. These are systems that do not have monitors and keyboards, or perhaps they do but it isn't convenient to use them. Some such headless users are fortunate enough to be able to run their systems continuously, but for those with their systems in bedrooms and the like, it is normally inconvenient to keep turning systems on and off. Content === Over time I have written several short utilities to enable headless computers to run with the minimum of effort. These are all for Linux, but could be easily converted to other Unix types. I hereby offer them to all who are interested! Descriptions js-shutdown --- This program shuts down your system when a button is pressed on a joystick. Consequently headless machines can now be powered down (as well as up) without requiring any login, either local or remote. A simple push-button switch can be used instead of a joystick. /etc/init.d/mprime.sh - Start and stop mprime automatically. Includes automatic log file redirection. clock-sync -- A simple program to time-step badly drifting clocks on bootup. This script can be run before logging has started. Why use this instead of the more professional NTP daemon? Because otherwise your logs will always begin with the wrong time, and only be corrected later. This program uses expect and rdate. status monitors --- Simple ways of remotely monitoring the progress of calculation programs. These involve simple additions to existing files. Download ftp://lettuce.edsc.ulst.ac.uk/gareth/distrib-utils.tar.gz Thanks to Brian Beesley for generously providing the hosting service. Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Hosting site for mersenne utilities?
I'm intending to release a small package of utilities that I have written which relate to the mprime program. I could host it at my ISP, but ISP accounts have their disadvantages, and I would prefer to have an independent account with a URL that won't change in the near future. Is there a well-known "semi-official" repository for such programs, or would anyone like to start one? Maybe someone has an FTP server which is going to be around for a long time that they can offer an account on? Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: GIMPS accelerator?
Daran, This is an interesting piece of lateral thinking that deserves to go further than I think it actually does. Essentially, I'm not sure how the operations that a graphics card can provide, such as line drawing, texture overlaying, raytraced light effects etc, could be made to implement a LL test or FFT etc which would require things like bit tests, conditioning branches and loops etc. Conceivably additions could be done by superimposing textures and reading back the resulting frame buffer, but these wouldn't be 64-bit precision additions! Maybe some form of matrix multiplication could be done by rotating textures before superimposing? However, I think the resulting calculation efficiency would be very poor, and may never achieve useful precision. Also, any code would be very hardware specific, and may only work if the display was not displaying, say, a desktop. However, if someone could implement it, it could provide the *ultimate* in Mersenne related screen savers! What you'd see on the screen would be the actual calculations themselves taking place before your eyes, and with no overheads for displaying it either! Yours, === Gareth Randall === Daran wrote: > > I know very little about computer architecture, so please feel free to shoot > me down if what follow is complete nonsense. > > GIMPS clients use the spare capacity of the primary processing resource within > any computer:- the CPU(s). But most modern PCs have another component capable > of performing rapid and sophisticated calculations:- the GPU on the graphics > accelerator. Is there any way that the GPU can be programmed to perform GIMPS > processing when otherwise not in use? If this could be done, then it would > have the effect of turning every client computer into an multi-processor > system. _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Thermal shock in CPUs.
Further, There might be two types of "movement" fracture damage occuring: 1. Movement between the substrate and the processor casing. This would be reduced if the thermal conductivity between these two parts is good, in which case both will expand together, rather than the substrate rapidly outstripping the still-cold casing. 2. Movement within the substrate itself. I suspect this isn't as significant since the substrate is thin, but if the floating point "region" expands rapidly while the rest of the chip is still cold due to heatsink inertia, then forces will be created within the substrate. Some real numbers might show this to be negligable, but small effects like this can become the most important when other problems have been solved. Ultimately, the forces generated by all movement will be reduced if the temperature difference between two parts is reduced, hence a slow(er) warming up would be beneficial. For instance, a quick jump from 68F to 115F is clearly worse than a quick jump from 85F to 115F, to quote John Pierce's figures. I suppose that, overall, thermal damage is not that significant, but unix users who are concerned can use the following: su mprime -c "sleep 120; $PRIME_BIN_FILE -d >> $PRIME_LOG_FILE &" & Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Thermal shock in CPUs.
Dear All, I've been thinking about the temperature fluctuations in a processor, and recalled the large and rapid changes in processor temperatures that some list members have reported when the floating point unit is activated. So my open question is: Do sudden temperature changes cause physical harm to CPUs, especially those that have only recently been turned on? Given that integrated circuits do not physically wear out, there are only two failure modes: 1. Decomposition of gates and other structures by thermal diffusion of doping agents. 2. Thermal stress. i.e. repetitive expansion and contraction due to turning on and off over time causes cracks to appear leading to failure. To my understanding, thermal expansion and contraction is the most important failure mode, and indeed machines that are run continuously are generally more reliable than those that are turned on and off each day. So: 1. Those who are lucky enough should run their machines continuously 24 hours. (Hey, you wanted an excuse to do that anyway?) 2. Are there merits in delaying the running of prime programs by a few minutes after turning on machines? For instance, a scripted startup could include a plain "sleep 120;" to allow the CPU to warm up slowly before the intense calculations begin. Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Getting new GIMPSers
Pierre Abbat wrote: > I know that there's an idle process (#0), an init process (#1), and many other > processes in a computer. Idle time accrues to the idle process. What I don't > understand is how 2:43 of the idle time was accounted to prime95 and the other > seventeen seconds to other processes - it should all have been accounted to > the >idle process. Bit late I know, but there are two other reasons for acruing idle time: 1. My Win95 system always started with ~23 seconds of idle time accumulated. On my system this implied that the counter started before the video display had even been initialised, which makes sense. The kernel is alive and counting long before you see your desktop, and it isn't until later that prime95 starts. 2. When prime95 (and mprime) communicates with the server, calculations stop. In fact this can't be helped. If a calculation has just finished then clearly no more work can be done. If a calculation is in progress it's possible to envisage "update" connections running as a parallel thread, but that could lead to race conditions if the work completes just as the communication is going on. (That's one guess on why it's single threaded, oh and it's a lot simpler to program!) (Note: My prime95 was replaced by mprime on Linux 6 months ago. If anyone was wondering about file format compatibility, I found that the prime95 file format is directly compatible with mprime.) Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: Spontaneous reboots
CPU overheating? Have you opened the case, and checked the condition of the CPU fan? It sounds as if the CPU is overheating once the FPU warms up. Is your heatsink sufficient? Is it full of dust? Open it up while the machine is running and check that the fan really is spinning, and at a decent speed. "Steinar H. Gunderson" wrote: > After being away for five days recently, I noticed that my computer > (running Linux kernel 2.4.1, by the way -- 2.4.2 now) had rebooted. > Just a few hours later, it rebooted again -- and that night, it rebooted > _again_. > > If I turn off mprime (v20), the problem goes away -- the computer > doesn't reboot, at least not the 36 hours I tested. After I start > mprime, it reboots in just a couple of minutes now. Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: [screen saver]
Dear All, Let's face it, why should people who are primarily interested in mathematical computation divert their time to writing rather unimpressive screen savers? There are already plenty of programmers out there who can do that job better! So... Simply have an online list of "recommended" / "approved" / "suitable" screensavers. No-one has to write anything new. We just test those which already exist, and analyse what resource demands they make in terms of CPU usage, RAM access, process image size etc. Such a list can then allow contributors to select their preferred screensaver, and avoids introducing extra development complications. Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: GIMPS slowdown due to California power problems?
Hopefully those responsible can reassure us that the servers are indeed running on high capacity UPS backup! A further question is what precautions the intermediate ISPs take to provide backup power for their leased line connections. Major hosting ISPs typically have enormous power backup facilities for their main systems, with diesel generators that can last days, but do they protect the routers for smaller leased lines such as the one which connects the GIMPS server in San Diego? [EMAIL PROTECTED] wrote: > > I would be more worried about the servers since they are in San > Diego. Imagine the possible data corruption. > > > I wonder if GIMPS throughput will be noticeably reduced due to > > California's power problems? Either by people shutting their pcs off or > > being knocked off when hit by a rolling blackout? Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Overclocking - bad for project?
There are occasional announcements about overclocking various processors, and I know that some Mersenne contributors describe their clock speed as xxx@yyy where yyy>xxx obviously. However, surely this project is one where overclockers do more harm than good? When you're running your favourite game, it doesn't matter if a couple of incorrect calculations creep in, but the Mersenne project involves very long calculations with basically a boolean answer at the end. One wrong result during this time could ruin the answer. Now I know that the algorithms include a lot of error catching, but once the processor is run to the point of instability there could easily be errors in the error protection. (I'll try a probability analysis later... Basically we need the probability of one error occurring within a certain number of instructions of a previous error.) My opinion is that it's better to have fewer correct results than to have the central database poisoned by loads of "don't think it's prime, but the user was overclocking" results, which of course cannot be distinguished from perfect answers. I'd trade two unreliable answers for one honest result. (What ends up happening is even worse. Mismatching checksums mean that the tests must be repeated until a consensus is reached.) A high score table is brilliant, and excites all contributors, but unfortunately a few seem more interested in climbing the table than in what the project is about. If people want to run overclocked, they should work on a project which isn't so sensitive to noise, such as SETI (okay, hardly an original suggestion here). SETI takes a noisy input to begin with, and introducing the odd bit of noise won't harm the results that much. People whose machines show any sign of instability at all should really stick to factoring, although these are just the sort of people who'll be issued with primality tests because of the apparently high performance. I'm tempted to say: go and find another high score table to climb. So after all that, here's a suggestion: How about an error counting system in mprime/prime95? (Okay there might already be one but I haven't seen it mentioned anywhere.) Every time an error is detected, a counter is incremented, and the final result sent back to the server. An answer coming back with 200 errors might be considered less reliable than one with no errors at all. Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Accessibility of compressed archives
Dear All, I'd like to mention two aspects of self-extracting archives which no-one has touched on. These are, security and accessibility. I like "inanimate" zip (or gz/bz2 in my case) for two reasons which I consider to be important: 1. No executable code: I can open the most untrusted zip I care to choose and know that I am not going to get any viruses from the self-extraction code. It is not ideal to force people to actually execute untrusted code before they get to see what is really inside, as most self-extracting programs require. 2. No platform dependence: I don't want to have a fully set-up machine of the appropriate architecture and with a working copy of the target OS before I can extract the archive. I want to be able to peruse the latest win32 prime95 download on, say, an Alpha running BSD, or whatever. Now as it happens both of these issues are of reduced significance in the case of distributing a program (prime95) which people are intending to execute anyway, and a program that is architecture dependent. However, documentation and data files distributed with the main executable may need to be accessed separately, and as a general rule self-extracting archives are more of a gimmick than a valuable tool (although I don't dispute that they help in some cases by reducing the amount of user interaction required to extract them.) [Note that I am not saying anything about whether there is any performance improvement in the final execution etc. I am only commenting on the file format for downloads.] Finally, I'm curious about the compression being better than zip. I've been wondering for some time about when the Burrows-Wheeler compression in bzip2 would make its way onto Windows. Is this a first example of it? Yours, === Gareth Randall === _ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Mersenne: Script to run mprime as a system daemon.
I have been running mprime on Linux for some time and have recently written a script
to make it run as a daemon on startup. mprime automatically nice's itself, which is
very neat and makes it ideal for running this way.
On my Debian 2.2 system:
Copy the enclosed script to: /etc/init.d/mprime.sh
You need to then create symlinks in the following locations:
/etc/rc0.d/K01mprime
/etc/rc1.d/K01mprime
/etc/rc2.d/S99mprime
/etc/rc6.d/K01mprime
Don't forget rc6.d! I did at first and spent some time being very confused.
Points to bear in mind:
Running mprime in a separate user account may be a good idea. This is because:
1. It is protected from anything you may do in your own user space. You can't
accidently kill it or delete its files. In the script I am running it as myself,
although this is a whole lot better than root.
2. Depending on your file permissions, other user accounts would be protected in the
unlikely case of there being a destructive bug in mprime, or any sort of exploitation
from the remote server. (Okay, the latter is very unlikely, but I work in Internet
security so it's always on my mind!)
Where compute intensive tasks are running:
1. Although not explicitly tested I presume that both tasks would be penalised by the
scheduler down to the lowest priority, and hence each would get 50% of the remaining
CPU time. This would impact any performance intensive games, for instance, so running
mprime as a daemon may not be such a good idea if you need to be able to turn it on
and off regularly.
2. The performance penalty will be worse than this, because some cache thrashing would
occur as the scheduler switches between tasks.
I have also included my earlier prime.sh script which I wrote for manually controlling
the mprime program. This is what I used before deciding the daemonise it. I made some
improvements for the daemon which aren't in this script, but you can edit those in.
I've pasted the scripts inline as I'm not sure whether attachments are allowed.
Start of mprime.sh
#!/bin/sh
#
# mprime.sh Script to manage "mprime" prime factoring program.
#
# Version: 1.1 11-Nov-2000 Gareth Randall
#
PRIME_BIN_FILE=/home/gareth/mprime/mprime
PRIME_LOG_FILE=/home/gareth/mprime/log/mprime.log
DESC="prime factoring program"
NAME=mprime
if !(test -f $PRIME_BIN_FILE) ; then
echo "Couldn't find $NAME binary: $PRIME_BIN_FILE" >&2
exit 1;
fi
case "$1" in
start)
if (pidof $PRIME_BIN_FILE > /dev/null ) ; then
echo "ABORTING: Process with that binary already running!" >&2
exit 1;
fi
echo -n "Starting $DESC: "
echo -n "START: " >> $PRIME_LOG_FILE
date >> $PRIME_LOG_FILE
su gareth -c "$PRIME_BIN_FILE -d >> $PRIME_LOG_FILE &"
echo "$NAME."
;;
stop)
echo -n "Stopping $DESC: "
killall -2 $PRIME_BIN_FILE
echo -n "STOP : " >> $PRIME_LOG_FILE
date >> $PRIME_LOG_FILE
echo "$NAME."
;;
*)
echo "Usage: $0 {start|stop}" >&2
exit 1
;;
esac
exit 0
End of mprime.sh
Start of prime.sh
#!/bin/sh
PRIME_BIN_FILE=/home/gareth/mprime/mprime
PRIME_LOG_FILE=/home/gareth/mprime/log/mprime.log
if (pidof $PRIME_BIN_FILE) ; then
echo "ABORTING: A process with that executable is already running!"
exit 1;
fi
if !(test -f $PRIME_BIN_FILE) ; then
echo "Couldn't find mprime binary: $PRIME_BIN_FILE"
exit 1;
fi
date >> $PRIME_LOG_FILE
$PRIME_BIN_FILE -d | tee -a $PRIME_LOG_FILE
End of prime.sh
Hope someone finds these useful!
Yours,
=== Gareth Randall ===
_
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