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United States

Export Controls on Beowulf? 229

Posted by Cliff from the interesting-thought dept.
Gary Franczyk writes, "The United States government has tightly controlled the export of "supercomputers" to certain other nations (i.e., China, Pakistan, India, etc.) for quite some time. Sun has had to deal with this numerous times when selling their equipment. How will the U.S. government handle the fact that now anyone with access to large numbers of PCs can create a "super-computer" cluster? I'm sure that the government is using Beowulf to do nuclear simulations right now... Who says that other nations cannot do the same? " Interesting thought. I'm not aware of any export controls on Beowulf, but with the U.S.'s views on cryptography, how will it be before such draconian views extend to any powerful computing technology? Is it even possible for the U.S. to restrict Beowulf in any way?
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Export Controls on Beowulf? More

Export Controls on Beowulf?

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  • restricting beowolf (Score:3)

    by nels_tomlinson ( 106413 ) on Monday February 28, 2000 @04:22AM (#1241067) Homepage
    Lets see: forbid export of NIC's, old 486 boxes, (ESPECIALLY if stripped down), cabeling, linux...


    Yep, that should keep the cat in the bag. It worked for cryptography, after all. Them furriners don't have kryptography, 'cause of our export controls.

    Oh, well.....

  • Well, the feeling I get when I read all those export restriction stories is that it applies only to hardware. If software would be included in the export control I'm afraid TCP/IP could be classified as do-not-export-to-some-countries software? :>. Anyways, I've always thought this supercomputer export laws to be pretty silly, what if the countries would just lease supercomputer time in the US, no need to export any hardware!

    J.
  • Apple advertised its G4 range a while back as being too powerful to export to unstable countries because the US government classified it as a munition.
    Off the record, however, Apple staff here in the UK told me that the USG didn't specifically restrict the G4, as there were other, more powerful systems that were already available on the general market that were more suited to tinkering with things beyond man's ken and other dictatorish type things.
    I'm assuming they were referring to things like Beowulf and various other Unix machines.
    IMHO the restrictions applied to older machines, back when men wore plaid and a gigaflop meant not having to say you were sorry...
  • In cases such as this, it may be worth exercising caution: nothing to do with the usual conspiracy theory, but what if these simple minded government/secret service types hadn't actually thought of the Beowulf as being a supercomputer?

    Anyway, that was just hypothetical, we all know that if China or Russia wanted to use Beowulf software against the US's wishes, they would do and there'd be nothing that could be done about it.

  • Beowulf != Supercomputer (Score:4)

    by -brazil- ( 111867 ) on Monday February 28, 2000 @04:23AM (#1241072) Homepage
    There is a big difference between a cluster of workstations and real supercomputers. Sure, they're both theoretically just nodes connected by a network, but the details are very different. Especially the networking of the nodes in supercomputers is about 2 orders of magnitude faster than even Gigabit Ethernet. Plus, you have custom compilers for that particular machine and its topology.

    I'm with the Technical University Munich, and the Leibniz Supercomputing Center next door is getting a new Big Box in March, which will then be the most powerful computer in Europe. The peak transfer rate between its nosed is 10 GIGABytes per second, IIRC. At the moment, thay're still installing the cooling units (the thing will consume about 600 Kilowatts!).

  • Well, they could try to go down the rediculous route they did with cryptography when they made it illegal to import and export crypto software... I think because the technology and concepts are very much in the public domain now they can not stop China et al. from producing clusters.

    THey could slap an export restriction on the technology, but that isn't going to have a huge effect.

    Ironically enough though although the US isn't allowed to produce any new weapons they are spending billions on making the ones they have more devestating...

    Or they could do what they usually do and invade any small countries and attempt to put illegal puppet governments in place...

    Go figure the fairness in that...

  • They can pass any law they want. But it won't work. Apart from limiting more than, say, exporting 64 processors to a single country per year, it cannot be done. Even limiting the number of purchases allowed per customer (which would make resellers overseas very, very mad) would not stop the government.

    If anyone can come up with a way to make this work, please, let me know (and don't let the government know, heh... you know they'd implement it)

    (oh geez.. getting bad mental images of laws requiring all exportable US chips to have a proximity sensor in them... )

    - Rei
  • What is a Beowulf cluster?
  • You can buy a pc anywhere right? You can get the code anywhere right? You can install it anywhere right? You can service it anywhere from anywhere right? What's the problem?
  • how will it be before such draconian views extend to any powerful computing technology

    You mean "powerful computing technology" such as the Playstation 2? [slashdot.org] If the U.S. govt can restrict it in any way, they probably will.

    Not that it is likely to make much of a difference by now. Just as anyone who wants DeCSS [csoft.net] can get it, anyone who wants Beowulf would probably be able to get it. There are no border checks on the Internet.

    ~~~~~~~~~
    auntfloyd
  • It is possible to buy perfectly normal computers of the type commonly used to build Beowulf-clusters outside of the USA.

    Assuming that say Iraq won't be able to buy a pile of Alphas, or K7's if they so wish is utter bullshit. The US may ofcourse choose not to export such computers to those countries, but what is to stop some person from buying the vary same boxes in some other country and shipping them to Iraq then ?

    It's not as if all countries have export-regulations equally silly as the US.

  • Export restrictions force creativity (Score:1)

    by Anonymous Coward
    Im sure that the government is using Beowulf to do nuclear simulations right now... Who says that other nations cannot do the same?

    There was a story on Slashdot a couple of months or so ago, and it said that since India couldn't get hold of an "official" supercomputer to do nuclear weapons -related calculations, they built their own cluster from consumer-grade PCs. (I think it was Beowulf)

    I think the logic behind export restrictions is a bit faulty. The fact is, if you can't get something out-of-the-box from the shelf, you have to be creative and go round that obstacle. And often the creativity which you are forced to use gets you solutions that surpass the existing ones.

    I wouldn't be surprised if Libya, North Korea, Sudan, Syria or some other nation in this weeks list of USA's Most Hated had come up with for example their own clever cryptography algorithms.
  • 1999.. Alpha 750Mhz 21264 CPU..
    2000.. AMD 1000Mhz CPU..
    2001.. Intel 1500Mhz CPU..
    2002.. Sun 1500Mhz UltraSparc5 CPU..

    There's no stopping them. Perhaps we should start rating supercomputers as any computer or cluster that can handle a teraflop? These are the days when your Dreamcast is even considered a supercomputer. Will governement ever learn to keep up with the times?

    - EraseMe

  • Beowulf is a linux clustering system which allows you to use stock PCs in parallel to get power equivilent to a supercomputer.

    Check out http://www.beowulf.org/ [beowulf.org]

    ~~~~~~~~~
    auntfloyd

  • Been there. Done that. (Score:5)

    by FascDot Killed My Pr ( 24021 ) on Monday February 28, 2000 @04:30AM (#1241082)
    I guess you haven't been hanging around Slashdot long enough. This came up and was resolved nearly two years ago [slashdot.org].
    --
    Here is the result of your Slashdot Purity Test.
  • Simply put (even though I'm sure other people will probably find some problem with it - they always do :):

    A Beowulf cluster is a way of setting up network of computers to symetrically process data. With enough computers in the cluster, you can equal the processing power of a small supercomputer.

    kwsNI

  • US government controls are becoming looser because of this kind of thing. There is no use in limiting US companies when equivalent technology is sitting on the web. OTOH: The Beowulf cluster is not an optimal architecture for every kind of problem.
  • Surely it would be easier to get a non-US supercomputer.

    Maybe most fast CPU's are made in countries that are friendly to the US and have similar controls and export rules, but surely these rules would be pointless if there is a single country without these rules that can make fast computers.

    Alternatively just do some serious overclocking. Just how fast can you make an only just about legal CPU go?
  • Name 1 - 1 task - that requires a supercomputer that can't be broken down into nodes well. Cracking crypto? Analysing radio signals? Doing nuclear tests? Running a genetic algorithm or ann extremely advanced neural net (not aware of any that take supercomputer speeds, but hey..).

    I, scanning my mind, cannot come up with a single task that cannot be implemented in a way that will lose almost no speed when made as a beowulf.

    Can you?

    - Rei
  • I assume the restriction defines 'potentially evil hardware' in terms of processing power, thus allowing the software to be exported without restriction. And since every node is a not-too powerful separate computing entity, the restriction can't be applied to the nodes either.
    So what can the government do? I can see three scenarios:
    1. No change, export of traditional supercomputers still controlled, beowulfs unrestricted.
    2. The ineffective export control lessened since beowulfs circumvent the restriction anyway, and the restriction was kind of stupid in the first place.
    3. The export rules get kludged in some ugly way to encompass clusters of computers. More pain, less fun for all involved parties.

    Oh, and imagine a MetaBeowulf cluster of those things! (Ah, the comment you all had been waiting for!)
  • ...and even if you didn't want to use "perfectly normal computers" then you could always go and talk to SuSE [www.suse.de] about buying one of their extremely funky clustering racks [www.suse.de] without having to worry at all about paranoid American export regulations.
  • Barcelona [maia.ub.es], Belgium [ucl.ac.be], Japan [kyoda.org], Cambridge Uni (the n hundred year version) [131.111.116.131], Italy [caspur.it] and Korea [korea.ac.kr] are just some of the places running Beowolf clusters. Its already out there, stop the shipping from the US of PCs and the software and it will be picked up from one of these places outside the US.

    Ma: Where is the horse ?
    Pa: She's bolted.
    Ma: Well you'd better bolt the door now.

    Things the US should stop exporting: McDonalds (eat British, eat Burger King :-), Windows and Sunny Delight.
  • I was begining to wonder how I could get my daily Beowulf [beowulf.org] fix with all those other stories. People have been downloading [beowulf.org] it and CDs [redhat.com] with it on are readily available all over the World.

    Oh-my-gawd even the Germans have one [mu-luebeck.de].

  • Well sure. But depending on your application, it might not be important. If your program is "parallelizable" enough you may not even need ethernet speed connections between your nodes (think distributed.net).

    Many types of scientific models which don't need fast communication spring to mind, like modeling individual photons traveling through a substance- here you would get more speed if you had a computer for each photon- not faster interconnections between nodes.

    /joeyo

  • The first person who starts talking AppleSpeak about Gigaflops and Apple and the G4 and how Macs are *sooooo* cool gets the death of a thousand swords!

    We're talking about processing units that are orders of magnitude beyond what a typical workstation can do, not processing units that are several percent beyond what a typical workstation can do.

  • It's the kind of machine with negative latency.
    Before you hit "Enter" the answer is already on the screen.

  • All the U.S. Government is trying to do is put on a big front and show...which allows them to crack down arbitrarily and forcefully on any entity (business or individual) who they see as a threat to their interests. The government sells more dangerous toys to foreign governments than ANYBODY. They're more interested in running the show than actually protecting world peace, so don't let them fool you.

    I used to think they were just damn fools, now I realize they're EVIL damn fools.

  • Name 1 - 1 task - that requires a supercomputer that can't be broken down into nodes well.

    Did you even read my posting? I said that supercomputers are also just a collection of nodes. The difference is in the infrastructure.

    I, scanning my mind, cannot come up with a single task that cannot be implemented in a way that will lose almost no speed when made as a beowulf.

    The you have no knowledge whatsoever of the kind of work being done on real supercomputers. Which is mostly simulations, i.e. solving differential equations. When I talked to the guy at the supercomputing center who showed us around, he said that on average, they managed to use twenty percent of their computers' potential computing power because the problems don't scale well to many nodes. This would be considerably lower on a Beowulf due to its slower network and no real compiler support.

    There are alos tasks (again simulations) that cannot be parallelized at all.

  • It is an Anglo-Saxon hunting party gathered around a large camp fire.
  • well, you named a big one: simulating nuclear tests. these and weather simulations really do need supercomputers. they involve millions (billions?) of particles interacting with each other. this requires the massive memory and interprocessor bandwidth that only supercomputers have. sorry, but no beowulf cluster can even come close.
  • Obviously. And, as I pointed out above, the cheap old stuff in the classified ads works just fine. Restricting these clusters would be impossible. There is an interesting article [aboutlinux.com] out there about a fellow in Taiwan who put together a Beowolf for Academica Sinica [sinica.edu.tw]. He is using it to replace some older SGI's. He said that one strong point of the beowolf idea is that he was no longer dependent on the US for parts. Saves lots of bucks, and sppeds things up immeasurably: no more waiting months for SGI parts to ship, clear customs, and so on.



    The point is, this whole idea seems trivial nonsense. That won't stop the government from trying, of course, if there is some sort of political gain in it.

  • My god, there is somewhere other than the good-old-USA? Does the government know about this?

    Of course the government knows about this. There are precisely 2 countries.

    One of them is the US. This consists of the North American continent and various parts of Europe as well as Australasia, the moon and various other small countries.

    The other country is called "Them", or possibly "Goodamn Commies". This consists of anywhere that isn't the US.

    The US and Them relationship has always been difficult owing to irreconcilable diffrences. The main one being US is right, and Them's wrong
  • OK, we all know that the US government owns the world, and that what it says goes, right?

    But, how exactly would it prevent Beowulf ending up in the hands of 'unsavoury' regimes?

    When, for example, AMD is manufacturing Athlons in Germany, and the code for Beowulf must be mirrored all over the world already, what does the US govt expect to be able to do?

    If they wanted to resrict large quantities of CPU's making it to these regimes, it would have to ban US chip manufacturers from building fabs abroad (not terribly feasible, legally). Even if they managed that, there would be nothing to stop foreign firms manufacturing chips.

    Then what would they do about the mirrored versions of the code? Shut down every Linux related FTP site in the world 'just-in-case'?

    This smells far too much like paranoia, and fuss over nothing, it ain't gonna happen, so why worry about it?

    --
  • Sure, there are applications like that. But my point was: there are also many problems for which a Beowulf is not suited. If there werent, people wouldnt shell out millions of $$ for real supercomputers (ours is going to cost about $30,000,000). But they do.

  • I laugh as I read this. (Score:4)

    by bons ( 119581 ) on Monday February 28, 2000 @04:42AM (#1241105) Homepage Journal
    "The United States government has tightly controlled the export of "supercomputers" to certain other nations (i.e., China, Pakistan, India, etc.)"

    Yes, and the easter bunny visits my house and leaves golden eggs on my porch.

    Try the following: ""The United States government has enacted legislation that attempts to tightly control the export of "supercomputers" to certain other nations (i.e., China, Pakistan, India, etc.)". Even then you mislead people, simply because of the word "export". The vast majority of the required parts are not made in the US. (Is there a single necessary part where all possible components that could be used are manufactured in the U.S.?)

    To keep a product like that in the hands of the U.S. only would require the creating corporation agreeing to do the following.

    • Keeping all manufacturing in the U.S. at U.S. wages.
    • Refusing to patent the technology.
    • Keeping a very expensive security lid on the entire facility.
    • Not releasing any details that would allow anyone with the resources of China to come up with an equivilent technology
    Yeah. Right.

    In a way, it seems silly to refuse to sell certain nations supercomputers when we still hire their citizens to work on our supercomputers...

    -----

  • The majority of powerful clusters, including a good number of beowulfs, do not run linux. Linux is just a nice, cheap way to implement a beowulf cluster. To determine whether or not your operating system is incapable of forming a decent cluster, run the following command

    if [ `echo $MACHTYPE $OSTYPE | grep -i "microsoft"` ] ; then echo "This system will never cluster decently."; else if [ `echo $MACHTYPE $OSTYPE | grep -i "linux"` ] ; then echo "This system will cluster decently" ; else echo "This system may or may not cluster decently"; fi

    - Rei
  • Things the US should stop exporting: McDonalds (eat British, eat Burger King :-), Windows and Sunny Delight.

    You forgot one thing: Cars!

    :-)

    Thimo
    --

  • Nuclear Simulations (Score:4)

    by nhowie ( 38409 ) on Monday February 28, 2000 @04:44AM (#1241108) Homepage
    I suppose a country performing Nuclear simulations isn't as bad as it performing tests (IIRC, the reason that the scary ASCI supercomputers where set up in the first place was to eliminate the need for nuclear testing), so this could be seen by some people as a "good" thing ...

    However, most nuclear tests these days seem to be for shows of strength (France and the India/Pakistan tests spring to mind), so it is actually more dangerous, in my view, to develop and test nuclear technology using supercomputers, than to develop and test them in "the open", since open testing is a good deterent to other countries.

    Perhaps there should be a clause in the GPL, that GPL'd software can't be used to bring about armageddon. OK, that won't work since: a) it violates the Open Source Definition, and b) Emacs would have to be removed from all sites;) - but at least require any nuclear technology developed under Linux be released GPL, maybe have nuke.soureforge.net. This would actually be cool, perhaps VA Linux could fund tests of the open-source nukes on some random place (off the top of my head - Redmond?), if an angry penguin running at you at 100mph is scary, what'll an angry penguin with a nuclear warhead be like?

    Sorry about the incoherence of the above post, it's been a long day (and it's only half-way through as well)
    --

  • hi all, i don't think that it should be restricted. the change in the crypto law's long overdue. too bad they didn't realise it until recently. i'm not in the US and it's nice to seee htat i can browse the web with a 128 bit enabled browser now. sure, you can create powerful stuff with clustering. berwulf is so cool!! but let's face it, the cold war's over man. stupid crypto laws just make everyone feel crappy ...
  • <soapbox>
    10 GBytes/s end-to-end between two processing units is quite unlikely, given high-end processors typically employed in supercomputers (like UltraSparc, Alpha, ...). The memory bandwidth of today's CPUs is not so gigantic, after all.

    The bisection bandwidth might be 10 GByte/s, though. And _that_ is hardly suprising - you can get Ethernet switches with 30Gbit/s backbone bandwidth for less then $20k these days ...

    The main difference between GBit Ethernet and tightly coupled network interfaces is the latency, i.e. the time it takes to send a message accross. Fractions of a microsecond for supercomputers, tens of microseconds for Ethernet.
    </soapbox>

  • Been there, Done that (Score:4)

    by jd ( 1658 ) <(imipak) (at) (yahoo.com)> on Monday February 28, 2000 @04:48AM (#1241111) Homepage Journal
    NASA AMES pulled the Beowulf directory, on the instructions of some official types who, according to the Beowulf site at the time, leaned rather heavily on the centre.

    You'll probably find the story in the Slashdot archives. People were mirroring the Red Hat CD and the Beowulf archives on every part of the globe, within an hour of the story breaking on this site. (I'm not joking! If there's any "wild exageration" it is more likely that of one of an hour being far longer than it actually took.)

    About two, maybe three, weeks later, the Beowulf site was back up and running. Almost certainly monitored, though. This was definitely munitions, according to someone with the clout to push a NASA site around.

    IIRC, though, Beowulf is really not much more than some finer tuning for the network drivers, PVM, MPI, and some freebie cluster management software. Most of the tuning was for the 2.0.x kernels and has since been incorporated into the main tree. PVM and MPI are freely downloadable, and there are later versions than on the Beowulf site. There are also lots of cluster management packages around, now, as well. Beowulf, IMHO, has ceased to be the specific patches/bundle released by AMES, and has become any collection of boxes, configured to act as a single, multi-node, supercomputer.

    And, yes, export of supercomputers is VERY restricted. Apple can't export any G3-based computers (though whether anyone in the rest of the world is upset by this is anyone's guess), and it's unlikely that newer-generation processors from other companies will qualify for export, either.

    (Personally, I suspect an overclocked, supercooled SMP K7 board would exceed the limits by quite a substantial margin.)

  • First of all, learn to turn bold off when posting in html once you're done with the boldfaced segment ;)

    Secondly, is the server only solving 1 differential equation? If so, what is this equation, "the universe works like.. ? If there are 10,000 equations being solved, they can be panned out to 10,000 nodes ("computers" if you're going to complain about my arbitrary use of the term "node").

    Third, there is nothing about a differential equation that cannot be paralellized. Even if each equation was dependant on the previous one, with no branching (highly doubtful) the algorithm to solve differential equations itself can be broken down. Its been a while since I took differential equations, but I don't recall an incredible need for a completely linear approach to solve them.

    Anyone know more about differential equations to back or refute this case?

    - Rei

    P.S. : "no real compiler support" - what are you talking about?

    P.P.S. : Is your "big box" costing more than 20% more than an equivalent beowulf? I'd be willing to bet it costs more than 10 times more. Thus, your 20% number (which seems kind of odd to me in the first place, I suspect poor code that wasn't designed to be distributed in the first place) falls apart.
  • Yeah, you're right, nuclear tests can't be done on beowulfs... wait a minute! Oh no, all of our government's nuclear simulations that they are currently conducting on beowulfs are impossible! Ahh, run for your lives ;) hehehehee

    Seriously :) Particle simulations are a great thing to distribute. You can give each node a "region" to process, with some common data accessable over the network. Each one processes their region, loading it into memory requesting data outside its region whenever it is nessisary for its calculations. Once its calculations are done, the common data region is re-submitted to the common data. I know this is a vast oversimplification, but this is how I would design a distributed particle system.

    - Rei
  • Came up.. ok. Was resolved, I didnt see any resolution or conclusion. In fact I didnt see any disagreement or discussion. Just pages and pages of people agreeing with each other. Maybe at this stage there are enough people reading that we'll get more than one opinion.

  • You forgot one thing: Cars!

    I don't really know anyone who'd buy an American car even though they're now available over here in the UK. Why would you want something that eats petrol like there's no tomorrow?

  • You cannot restrict Beowulf. Period. (Score:4)

    by Noryungi ( 70322 ) on Monday February 28, 2000 @05:01AM (#1241117) Homepage Journal
    As many people have pointed out Beowulf clusters cannot be restricted, precisely because they are clusters and not one machine.

    Let's go through this real quick:

    • Sales of individual PC are usually not restricted. A rogue nation (say, the dangerous black-listed terrorist country of "Freedonia") could put together a dozen decoy companies, who then proceed to buy either complete PC or enough spare parts (motherboards, CPU, RAM, HDD, netword cards, etc...) to put together a nice 100+ nodes cluster. To avoid suspicion, just pretend company XYZ is getting started and needs to put together its LAN with 10 computers. Multiply by 12 or 15 different companies and voilà: your Beowulf is ready for delivery! You can even get brand-name machines, and you supplier will probably throw in a laser printer for free!
    • High-speed routers/hubs can be had in the same way as above. Just mention the LAN has to be powerful because you want to exchange huge graphical files...
    • Linux/FreeBSD distributions can be had over the Internet for free. Or, you can just walk into any computer shop in the western world with $20 in cash and come out with what you need. No hassle, no paperwork, no problem.
    • Most Beowulf related information is available for free on the Internet. Just make sure you use a 'net connection that can be traced back to an unrestricted western country (say, the UK) and download all you want. After a little while, either burn a couple of CD-ROMs with all he information you need or just do a hard copy and ship everything back to Freedonia.
    • Put some of your best and brightest brains on it, and your Beowulf cluster should be humming in no time, happliy crunching the numbers of your H-Bomb secret project.
    • Hardware failure? Need more CPU power? Just repeat the steps above!


    That's all there is to it, as far as I know. I should add that many "Freedonias", during the cold war, used the exact same procedures to illegally acquire hardware they were not allowed to buy... There are even tales of the (old) USSR acquiring Cray machines, when these were the "crown jewels" of US computing. Commodity hardware has just made this 100 times more simple...

  • Apple (Score:3)

    by Kaufmann ( 16976 ) <<rb.moc.opmilo> <ta> <ladenr>> on Monday February 28, 2000 @05:03AM (#1241118) Homepage
    Apple can't export any G3-based computers (though whether anyone in the rest of the world is upset by this is anyone's guess)

    Gee whiz, in that case the iMac that has sat in my desk since October 1998 is just a figment of my imagination, right? I've been dreaming about it all along, eh?

    Apple is forbidden to directly export one specific model: the G4/500MHz, which exceeds 1 GFlops and is therefore subject to "supercomputer" regulation. But iMacs, iBooks, "big" G3s and more recently "big" G4s can be found all around the world, including here in Brazil. (Okay, so they're all priced like supercomputers... but that's not the issue :)

  • Why would you want something that eats petrol like there's no tomorrow?

    For the same reason you should smoke cigs - big cars make you attractive to the ladies.

  • The Beauty of Linux and Friends (Score:1)

    by Anonymous Coward
    Thats the beauty of Linux and Friends:
    It is open (like open in can of worms :)
    Prohibiting Beowulf export would be
    like giving orders that the wind has to quit
    blowing around.

    You could do it but things wouldn't change too
    much. That's another reason why I love Open
    Sources and the people behind this effort.

    Hint: The Electronic Frontier Foundation [eff.org] is engaged in
    fighting to defend your personal rights
    and your freedom on the Net. If you feel
    that what they do is in your interest, then isn`t
    it time for you too to support them?

    Put your money where your mouth is (and interests are)
    and join the The Electronic Frontier Foundation. [eff.org]
    It costs only 35 bucks/year (students even
    cheaper, 10 $ I think).

    I did it and I'm a proud EFF member now. When they
    sent me my membership certificate, I was
    ashamed to find out that there are less then 9000 members
    so far. Shouldn't there be hundreds of
    thousends of members instead?
    Take your girl/boy friend one time per year and
    stay at home (show her/him your new Linux box)
    instead going to the Sushi parlor. You spare
    the bucks for the EFF and you'll have a lot of fun.

    You can be the first of those new members. Don't delay.
    Browse their web site NOW [eff.org]
  • Well, lets see... I determined a little bit back back that you could get.. what was it... 17 ghz distributed, I think.. for 3000$ (it was based on dual celeron 366's overclocked to 550 (there was an article on slashdot a while back on how to do that)) (remember, it would actually be running faster than a 17 ghz system made of 550s because every part of the chip gets clocked up) with 32 megs of ram per box (no local hard drive) and 100 mbs ethernet. I plan to build a system like this as soon as I can scrounge up the money, btw. (BTW, before you start trashing 100mbs ethernet, remember that Avalon uses 100mbs if I recall correctly, as do several other large systems - most tasks can be designed in a way to run like SETI@HOME does, wherin a single batch takes up hours, if not days on a system).

    Anyways... ;)

    Scaling that 3,000$ figure to your 30,000,000$ figure, we end up with a result of 170 Thz, minus latency (which, as I already stated, can be generally brought to a minimum by forethought on the software design). To be realistic, some of that money will need to be saved for nodes that fail (while if any part of your supercomputer fails the whole system I'd suspect goes down, but we'll pretend that doesn't happen), and we'll assume the beowulf costs more to set up and operate, so we'll sap a good bit of that money away and end up with.. oh, lets say 20,000,000$ budget, and settle for our measly 120 Thz system. Oh, the humanity.. ;)

    Now, how fast is your system?

    - Rei

    (Disclaimer: I am fully aware of the fact that these are Intel x86 mhz and are in no way, shape, or form relateded to the number of Mhz his system uses. However, even being nice and assuming that each operation of his supercomputer takes only 1 clock cycle, and his calculations used only the slowest operations, you wouldn't get much more than a 10fold speed increase per mhz)
  • First of all, learn to turn bold off when posting in html once you're done with the boldfaced segment ;)

    No, I should learn to use that preview feature.

    Secondly, is the server only solving 1 differential equation? If so, what is this equation, "the universe works like.. ? If there are 10,000 equations being solved, they can be panned out to 10,000 nodes ("computers" if you're going to complain about my arbitrary use of the term "node"). Third, there is nothing about a differential equation that cannot be paralellized.

    To be honest, I myself know very little about differential equations. It's definitely not one equation, but interdependent systems of equations. Anyway, someone whos writing his master thesis on the stuff told me that hes doing simulations (of some sort of circuity) that can't be parallelized.

    P.S. : "no real compiler support" - what are you talking about?

    Ideally, you have a compiler that takes care of using all the nodes and distributing the code. If you have to hand-code all that, it just takes too long and is error-prone (debugging distributed code is a really/i> ugly task). Something like High Performance Fortran.

    P.P.S. : Is your "big box" costing more than 20% more than an equivalent beowulf? I'd be willing to bet it costs more than 10 times more. The point is that there is no "equivalent" Beowulf! It's designed to solve problems that a cluster of workstations simply isn't fit for.

    Thus, your 20% number (which seems kind of odd to me in the first place, I suspect poor code that wasn't designed to be distributed in the first place)

    No, it's code that simply cannot parallelized with 100% efficiency.

    And your question about the cost seem like you didn't understand what I wanted to say. These supercomputers spend 80% of their CPU cycles doing nothing because they work on problems which can't be parallelized perfectly. With a Beowulf cluster, the percentage would be higher, and it would keep increasing with the size of the cluster, so that it simply is not possible to build a Beowulf cluster that would solve the same problem faster.

  • I don't really know under what license Beowulf goes, but as far as I'm concerned,GPL is here to garantee that free software remains free (i.e. as in freedom).

    Secondly, the US shoot themselves in their own ass with all these export regulations, why? Well because here in Europe, we don't have export restrictions for countries like Cuba and Iran.

    No sirrrrrr, even the USA wanted to stop us exporting to Cuba, but they didn't as Europe said 'We don't like that guys', and Clinton never signed.

    I think those USA export restrictions are isolating the great super-power, but I don't mind, I think American attitude can be very arrogant sometimes.

  • Check here to find out [overclockers.com]

    (hope I got the URL right)

    - Rei

  • This is what we call a "Milchmädchenrechnung" (milk maids computation) in German.

    The point is this: with distributed computing, it is totally ridiculous to just add up the clock speeds of individual processors and expect the result to be in any way meaningful. The reason: When attempting to solve the kind of problems the $30,000,000 system is designed to solve your 170THz would disappear down the idle loop because each processor would spend 99,9% of its time waiting for data to be fetched over the woefully-underpowered ethernet LAN.

  • On a similar if slightly tangential note...

    My father, 30 odd years ago worked in Nuclear weapons research for a year after university.

    Every few weeks a russian nuclear warhead would turn up unnanounced outside their office and they would analyse it.

    Once he asked how they smuggled it out joking 'Does somebody just walk out with it under their coat.'

    The reply was a simple knowing look and then the supervisor walked off...

    Scarily to the entire British Nuclear stockpile was held at the base he was at which was a small site near Seven Oaks in Kent which, like all research establishments was only about 2 percent above ground...

    Oops, just breached national security... Bugger.

  • Where exactly are these nuclear simulations being run on Beowulfs? We aren't doing it in Los Alamos' X Division and I don't know anyone at Livermore's A or B Divisions doing it...could it be that you don't know what you're talking about?

    Jim, speaking for himself.
  • The Apple PowerMac G4 is a supercomputer according to the out of date export control laws. A supercomputer is defined as being capable of performing 1 billion floating point operations per second, ie 1 Gigaflop. Can anybody tell me what threat to national security a G4 is?
  • >>Things the US should stop exporting: McDonalds
    >>(eat British, eat Burger King :-), Windows and
    >>Sunny Delight.
    Damn straight!

    >You forgot one thing: Cars!
    Take a look in the most recent Popular Science. There's a cool little concept car from Chevy called the Tandem 2000. It looks like a jet aircraft's cockpit on four wheels. Wonderful little machine. I hope they start production on them, I'll need something to replace my '91 VW Golf in a year or so...
  • While it might be true that the supercomputers efficiency to deal with applications specifically written cannot be argued about, it is also true on teh same count that the excellent refurbishing of the old machines into high performance Beowulf clusters has meant that the power of having superior and faster processor power has gone from the hands of the few who could afford it to teh hands of thousands who need this power and afford it as well..

    Dont get me wrong here. its nothe average home user who would like to go and build a 200 processor beowulf cluster.. but more the universities and institutions who have been wronged by the US government from buying these so-called munitions for legitimate computing purposes..

    from a technical standpoint, the argument that beowulf clusters simply cannot stand up to the computing power of supercomputers can be accepted to an extent and thats the way it will be for sometime..

    as mentioned elsewhere.. its true that languages like c/c++ are not the best for parallel computing but more high perf fortran because of its native supportin the form of parallel lbs for faster computations.. so there are other considerations for evaluating the perf of supercomputers v beowulf cluster..

    my 2 cents ..

  • Beowulf availability. (Score:1)

    by Anonymous Coward
    Guys guys guys, Do you really think that if there would be export restrictions on Beowulf-like systems' source code that would stop (blacklisted countries) from obtaining such source? and besides, even if they don't have it already (which they do) why can't they write their own? after all, they've got the skills the power the money and will do to do, nothing will stop them, not even a funny thing such as export restrictions on source code. Beowulf-like systems are not something new, nowdays, many people know of such because of the Internet and mostly Linux, such systems have existed and had been running for ages, all over the world. This discussion is rather pointless.
  • No Task Cannot Be Distributed.

    Here's the basic structure of an algorithm that builds on its previous results

    while (TRUE)
    {
    a=Func(a);
    }

    This cannot be broken down. However, unless Func is also structured like this, it can be broken down. Now, what could you accomplish if func is structured like this? Nothing, it would have to be calling subfunctions that actually do something, as demonstrated below.

    while (TRUE)
    {
    a=Func(a);
    }

    void *Func(void *a)
    {
    long i;
    for (i=0; iloop_size; i++)
    {
    a=Func2(a);
    }
    return a;
    }

    etc. You can do as many layers of this as you'd like, but eventually you have to get to a function that does something.

    void *Func2(void *a)
    {
    long i;
    for (i=0; i100; i++)
    ((char *)a)[i]=((char *)a)[i]+1;
    return a;
    }

    This last example can be broken down into

    void *Func2(void *a, int thread)
    {
    int i;
    for (i=thread*5; ithread*5+20; i++)
    {
    ((char *)a)[i]=((char *)a)[i]+1;
    }
    return a;
    }

    (this example uses 5 threads, accessing a common memory segment).

    As I was saying, any task (please correct me if I've made an error in my thinking here) can be broken down into multiple threads. The efficiency of these threads, now, comes into question, but with the price of supercomputers, a 100fold loss in speed in a beowulf is often justified. And you'll only get a 100fold loss of speed on something like, perhaps, calculating a bunch of random numbers (seed builds on the previous one) - where the innermost function has an extremely low latency. Not a very common thing in real-world calculations.

    - Rei


  • You seem to have this misguided preconception that beowulfs have exponential speed loss. This is horribly untrue. Lets say you have a system like seti@home distributed. You're sending data once every *day* on a certain box across the network. Even with 86,400 nodes, you're down to a batch request/submission once a second.

    Once a second!!!!!!

    Learn to think clearly. beowulfs do *NOT* lose speed exponentially. Period. End of case. Do you understand?

    - Rei

  • Clustering technology is too widespread to limit (Score:3)

    by maynard ( 3337 ) on Monday February 28, 2000 @05:39AM (#1241138) Journal
    While the Beowulf patches come out of NASA, there's a whole bunch of stuff out there which isn't written in the US at all. For example, the best session clustering technology for Linux is MOSIX [mosix.org] which is put out by Hebrew University in Isreal. To my knowledge this isn't export restricted at all, and is released as a set of patches against the main kernel tree. Anyone with basic System Administration skills could set up a Mosix cluster pretty quickly.

    If you're less interested in interactive clustering and need computational load balancing instead, there's a whole slew of batch queuing packages available from GNU QUEUE [yale.edu] to the many derivatives of NQS out there. Here's the a href="http://www.cmpharm.ucsf.edu/~srp/batch/syste ms.html">Yahoo Batch Queuing Page" for a short list of many popular packages.

    I don't think the US government could stop any nation from purchasing commodity hardware manufactured from around the world, installing a basic Linux or BSD distribution, and setting up a batch queue or other type of basic cluster. Never mind that a sufficiently serious government could just up and write their own... in my department at BBN (Speech and Natural Language Processing) we use an internally written batch manager which is surprisingly simple... all written in C.
  • AVALON [slashdot.org]

    Oh, of course, I know nothing about what I'm talking about. Beowulfs are never used for particle system simulations. Especially at Los Alamos (read - SARCASM). Apparently you don't know what you're talking about. Go to hotbot.com, search for beowulf and particle. The second site on the list has hundreds of beowulfs listed, of which I'd bet half of them are used for physics research using particle systems of various kinds.

    Please, before you post uneducated drivel and attack me, please pay attention.

    - Rei

    P.S - Have you ever worked on distributed code before? Hmm... guess who, in this thread, has...
  • All the restrictions in the world cannot alter the intent of another nation. If you treat someone (or a nation) with suspicion, interpret their every move as hostile, and generally bully their citizens, is it surprising that negative attitudes form? Now that the Cold War is over, perhaps a more enlightened foreign policy could be forged based on a more consistent set of principles?

    In my mind, the export of "munitions" like Beowulf pales in comparison with past doctrine now being slowly exposed such as military training given to the Indonesian special forces which rebounded badly in the Timor Separation. Certain Latin American countries have no particular appreciation of the US "aid" that they received in the past either (Panama, Niguargua, Columbio, Haitii, etc).

    The steadiest water stream can erode the strongest rock. A consistent message of rule by law, respect for human and property rights, and civil society will do more in the long-term in altering societial values than bombing the living daylights out of people whenever they step over a dimly perceived line. By watching TV, the Chinese have gained respect for western police reading people's rights when arrested (not a common occurance for a society slowly emerging from fuedal warlord times). By consistently demonstrating the virtues of a open society, with the free exchange of ideas, even when that could put us in a perceived position of vulnerability (with a decent armored cluebat hidden out of sight just in case), moral authority can be maintained. Even though many people do not share RMS views, they do respect his passion for sticking to his principles. Leadership, especially in the global setting, should be more setting an example, not trying to blugeon or bully people into following your lead blindly. When a giant, walk softly and bend down to listen sounds like a good analogy to get along with normals.

    The Beowulf example is like trying to stick a finger in a dam when the whole ediface is changing, about as useless as patenting the click when everyone is moving on beyond the mouse. Similar technology exists in Isreal and could be duplicated given enough time. Given the basics of enough food (a recent Nobel winner proved that most starvation resulted from bad distribution systems, rather than absolute lack of food) and some decent shelter, the average citizen from other countries are much more interested in sitting down and knocking back a few beers than in the posturing antics of self-opinioned leaders on a media crusade. And ultimately it is the average citizen that benefits from openess when they can vote with their feet.

    If they can afford to build a Beowulf then ship them the CDs and invite them to join the GNU revolution.

    LL
  • end to all this surprise? Every story like this on /. is always, "Whoa, look. So and so is providing linux drivers." At what point are we going to stop being suprised and expect linux drivers in the same way we expect Windows drivers? Just a question ...
  • Erm, that is: Avalon [slashdot.org] (I misread an 'l' as a '1')

    - Rei

  • One thing to distinguish the Playstation 2 and a beowulf cluster is that the playstation 2 is hardware and beowulf is, more or less, an idea. The analogy that I've read in earlier posts that seems right to me is to compare restriction of beowulf clusters to encryption. The way I see it:

    1. It's hard to control export on software source code unless one controls export of totally available ideas. This point makes export controls difficult.
    2. Much of the beowulf technology, like much encryption technology, is developed outside the US. This point makes export controls worthless.
  • If they don't have supercomputers to simulate nuclear experiments, they will do real ones. Which do you prefer? Myself, I prefer to sell a supercomputer than to see an atmospheric nuclear test
  • Crap

    I was just laughing at the guy the other day who posted the comment about forgetting which story he was replying to. Well, this comment should be over in the Wavelan story. (If I still remember.)
  • Heh, they should burn the decss code into a ROM on the Playstation II. Well there are no border checks on the Internet _yet_. I'm sure some people are working on that problem.
  • Avalon [lanl.gov] (You can tell I don't do web work, heh... forgot the http)

    - Rei
  • You're confusing a particular problem (signal analysis) with the machine being used to solve it. The loss of speed depends highly on the problem. What Seti@home does, as well as brute force encryption cracking and raytracing, to mention some examples, happens to be a problem that allows the nodes to do their work with nearly no communication.

    This is not the case with other problems. With those, you need high-bandwidth, low-latency communication between the nodes, and that is something you simply don't get out of Ethernet, which, actually does have exponential speed losses when the network comes close to saturation.

  • Between a computer and other devices like a SonyPlaystation 2, Which if I read the specs in the trade pubs correctly has roughly the same floating point performance of an SGI Iris Indigo. But I can't imagine the govt attempting to restrict a Japanese company's ability to export.
  • That's right. I worked on an university project that dealt with a N-body simulation. We had implemented the solution using the C library MPI, which does message passing around the nodes. The task was to reduce the passed messages. The same code ran on a 26 node Cray supercomputer and on my 2 node home (not beowulf) linux cluster. That was real scaling code ;-)
  • If you look at the latest list of the world's fastest supercomputers, you'll notice that govt. labs have most of them. And those are just the one that are declassified. I don't think that U.S. weapons labs buy cheap Beowulf clusters when they have tax dollars to spend.

    I do research in astronomy and astrophysics, and Beowulf clusters are common throughout my field. Many international collaborations happen on the same cluster, so it's too late for export restrictions. And are we supposed to take all those Beowulf HOWTOs off the web?

    Let's put export restrictions on our politicians -- no more expensive trips to Africa, China, and wherever else their daughters want to go.
  • You saw (I hope) my post above where I broke down the steps in converting a linear process into a (basic) distributed one.

    Please present a realistic code sample that will accomplish something useful and yet not scale well over a network. Be forewarned that, as a general rule, the more complex the task (AKA things that apply to the real world) the better it breaks down into a distributed environment, as a general rule.

    Theoretical, pointless mathmatical calculations (*dons asbestos suit to protect self from math majors*) may be simple enough and few enough in number in the inner loop to prevent a beowulf from getting that 100x better performance ratio it needs to beat out a supercomputer... but a real world, useful task? I honestly doubt it.

    Once again, I request a code sample that shows something useful being accomplished that can't be broken down.

    - Rei
  • I was going to look you up on the net, yet your bio shows almost no info. In fact, the only thing I found useful in your bio was your web page... which doesn't work (broken link). I'd fix that :)

    - Rei
  • The USSR probably had Crays imported from Switzerland. You know they may look like a western country (no export restrictions against them) but are actually neutral so they wouldn't mind selling to the USSR. I assume that the US itself could have directly traded with the Russions, it would not be too surprising...
  • I bet we could make a Beowulf cluster out of these!

    Huh? We're already talking about Beowulf? Dammit.
  • Beowulf is nothing more than a bunch of PCs, connected via medium speed (100mbps to 1gbps) networking, running one or more of a couple particular software packages. Both pvm and mpich
    have been readily available, to the whole world, for a long time. MOSIX has also been available for a long time (though not on Linux)

    In short, you can't restrict Beowulf because there's very little there to restrict. For example, mpich based parallel programs can very easily be recomiled on FreeBSD, and the performance is better. (yes, FreeBSD does have better networking. See http://www.cs.duke.edu/ari/trapeze/ip/ for some real benchmarks.)

    Besides, MPI is a documented protocol, so even if implementations were banned, it shouldn't be that hard to re-implement from the protocol descriptions.

  • Re:Beowulf != Supercomputer. So? (Score:3)

    by Claudius ( 32768 ) on Monday February 28, 2000 @06:20AM (#1241163)
    Many problems do not parallelize well. For instance, to my admittedly limited knowledge no parallel version of the fast Fourier transform algorithm (which serves as the backbone of many spectral and pseudospectral codes) is known which does not require a prohibitive amount of interprocessor communications.

    At the risk of being overly pedestrian, let me try tackling your differential equations question: Communications latency issues can crop up even if you have just a single equation to solve. Let's imagine, for the sake of discussion, that you wish to understand the propagation of heat on a metal plate, and you have a differential equation that describes the process. Conceptually, you might imagine solving this problem on a parallel computer by breaking the metal plate into a bunch of smaller regions, and asking each processor to compute heat flow on an individual region, as in the following, where a plate is broken into 9 regions:

    OOO
    OOO
    OOO

    You can see that every region borders other regions, and herein lies the difficulty: To compute how heat propagates in any one region, say the top left corner, you have to have information from each of the neighboring regions. (In the case of the top-left corner, it'd be the center-left and top-center domains). In solving differential equations, this information is called the "boundary conditions." Each time step would require sending a considerable amount of information among the processors in order to handle the boundary conditions. To use a real-world analogy, if communication latency is high, then many of the processors will end up waiting for the information they need, much like workers in a bureaucracy that has an inefficient internal mail service. In "real" supercomputers you pay big bucks for fast communications, and problems that are communications-intensive will naturally perform better on these machines than on Beowulf or Appleseed clusters. Alternatively, problems whose algorithms require few messages to be passed among processors (many Monte Carlo algorithms have this feature) may run very efficiently on a Beowulf or Appleseed cluster, where communications latency is high.

    Parallel computing seems to be largely an exercise in economics. Any parallel algorithm with a nonzero number of messages to be passed will necessarily run at something less than 100% efficiency. Just how far below 100% depends on the nature of the algorithm and the machine/cluster it is running on.
  • For some Parallel tasks a Beowulf is just as effective as a supercomputer. The problem as you state it is whether your algorithms require very fast communication between the nodes.

    My understanding for export controls of supercomputers is to restrict the (or at least make difficult) the ability of non-US powers to intercept and brute force decrypt US communications. Current decryptions can be done without the need for communication between processing nodes (and technically without the need for a Beowulf - A load of standalone PCs will do just as well). A Beowulf is a cheap solution to exercise parallel communications capable of brute force decryption so for this project an actual Supercomputer would be overkill.


    This message was exported from the United Kingdom in accordance with the export administration regulations. Diversion contrary to UK law prohibited.
  • Export of High Performance Computers (HPC) are restricted based on Millions of theoretical operations per second (MTOP) or the aggregate of Composite Theoretical Performance (CTP). See http://www.bxa.doc.gov/HPCs/Default.htm.

    Countries are broken down in to Tiers and are subject to export license restrictions based on Tier and CTP. There is a chart at http://www.bxa.doc.gov/HPCs/ctpchart.htm that shows the provisions.

    And if you dig deeper into Parts 740.7 and 742.12 of the Export Administration Regulations you find this:

    exerpt from Category 4 - Computers

    b. "Digital computers" having a "composite theoretical performance" ("CTP") exceeding 2,000 million theoretical operations per second (Mtops);

    c. "Electronic assemblies" specially designed or modified to be capable of enhancing performance by aggregation of "computing elements" ("CEs") so that the "CTP" of the aggregation exceeds the limit in b.;

    How the US Government thinks it could ever enforce this with Beowulf is beyond me...

  • Aaagh! Country and Western is the music that would be playing in hell IMHO. There I'd be forced to wear cowboy gear with tassles and engage in formation line dancing for all eternity...

  • Re:Beowulf != Supercomputer. So? (Score:5)

    by QZS4 ( 7063 ) on Monday February 28, 2000 @06:52AM (#1241175) Homepage

    Name 1 - 1 task - that requires a supercomputer that can't be broken down into nodes well

    Sure, I can name several. Just some examples: Weather simulation. Ocean simulation. Molecular simulations. Simulation of astronomical bodies. All of which are very real problems.

    In short, any problem which is not trivially parallel will get a much poorer speedup on a NOW (network of workstations) versus a real supercomputer. Many of the problems above will generate many MB/s of data per processor (60 - 200 MB/s is not uncommon).

    What you fail to realize is that many problems run for many iterations, and for each iteration you need to distribute the global dataset to all worker nodes. Take the Barnes-Hut program, for example. In that program, each node get a set of close-by astral bodies (stars and planets), and calculates their new positions for the next time step. To do that you need the positions of all other stars. For the next time step, you need to a) collect the calculated positions from all worker nodes, and b) distribute them back for the next iteration. When trying to run that on a NOW, you will very soon find that doubling the size of the cluster will not give any speedup at all, since they will spend most of the time chatting with each other on the network. On a supercomputer, you can run many more worker nodes before this happens.

  • >> P.S. : "no real compiler support" - what are you talking about?

    > Ideally, you have a compiler that takes care of using all the nodes and distributing the code.
    > If you have to hand-code all that, it just takes too long and is error-prone (debugging
    > distributed code is a really ugly task). Something like High Performance Fortran.

    Are you aware that there are HPF compilers for Linux being used in Beowulf clusters?

    Check out:

    VastHPF [psrv.com]
    PGHPF [pgroup.com]

    There are other commercial products, plus some educational type compilers.

    - Darren
    --

  • If you take a look at the hype on www.beowulf.org shutdown [slashdot.org], and Important Beowulf notice [slashdot.org] stories. Now, I know there was great debate over what *really* happened, but one of the possibilities that was a concern was exactly what you are asking about..
  • There actually is one car I'm considering, it's the Chrysler Neon. And maybe a Viper, but that one fits your description with extreme precision. :-) I still cannot understand why all Americans are driving farmer's vehicles (pickups).

    Thimo
    --
  • Consider the longstanding battles over encryption software export. Does anyone honestly believe forreign governments couldn't manage to get their hands on the 128-bit version of Netscape? Come on! Yet, the government still interfered here. It's important to remember this.

    With all due respect, I fail to see why

    First of all, please use the term "US Government". The US Government is the one that is at stake here. Other governments may or may not have the same kind of prohibition when it comes to supercomputers and "sensitive" countriesand/or uses.

    Second, as I pointed out (and as you said yourself) regulations won't help the US Government stop the export of Beowulf clusters, precisely because the technology required for Beowulf clusters is available everywhere.

    What matters is that, by putting regulation into place, the US government can now prosecute anyone who willingly exports that technology to "Freedonia" or any other terrorist country.

    Since most of the people who run these countries are far from stupid, they'll simply execute some variation of what I outlined above: buy the technology as discreetly as possible, probably not in the US, through decoy companies and then ship it back to where they need it. US regulations will be avoided -- but these US regulations will be available in the case anyone is stupid enough to think they can directly sell Beowulf clusters to Freedonia or whatever.

    Just my US$0.02...
  • Now, I'm CERTAINLY no expert on the subject, but I must beg to differ. Weather simulation *CAN* be broken out to run on a distributed machine, which is proven by the fact that several government entities have awarded contracts to build them to just such machines!

    I also believe that perhaps you are unfamiliar with a good cubic beowulf setup. Typically, each machine would have 4 Gigbits of bandwidth to transfer data, i.e., 4 Gigbit ethernet cards, no more then 2 hops from any given machine. Using this method, transfering the datasets is fairly trivial. Granted, *THIS METHOD DOESN'T SCALE AS WELL* if you use the same programming techniques as those one would use on a supercomputer scale. However, this can be overcome if you take this into consideration, aka, clusters of 9 cluster machines. Each machine would really only be talking to one of 9 machines, with the cluster controller talking with the other controllers. It's just a different way of looking at the problem.
  • I spoke to Michael Reagan on the air about this very subject about 8 months ago. Some people (like mike) just don't get it. What Mike was talking about was the Clinton administrations easing of computer export restrictions to countries like China.

    The Genie is out of the bottle. Beowulf, actually allows one to build faster computers for LESS money. If you buy a "million dollar" super-computer and you spend a million dollars on nodes for a Beowulf cluster, typically the Beowulf if going to be capable of doing the work faster.

    I'm not too worried about China getting nuclear technology through eased export restrictions, I'm worried about well funded terrorist groups getting access to nukes, Bin Laden's boys or that death cult in Japan are far scarier to me than China.

    LK

  • Re:Beowulf != Supercomputer. So? (Score:3)

    by Claudius ( 32768 ) on Monday February 28, 2000 @08:04AM (#1241203)
    Wow, someone who knows what they're talking about....

    I deceive people well. :)

    If I understand correctly, you are describing how a "surface-to-volume" ratio goes up as the volume elements get larger, thus allowing individual processors to spend more time crunching numbers and less time waiting for boundary data. This is indeed true, and this is precisely the kind of balancing act one has to perform to compute efficiently in parallel. As you've demonstrated, the same algorithms may be more efficient on some machines than on others, but based on my (albeit limited) experience in computational physics, optimization almost always seems to boil down to how one reduces the number of messages that have to be passed in order to perform the task. This seems to be the single most important factor in the scalability of numerical calculations (how much speedup is gained by increasing the number of processors).

    Disclaimer: While I have some experience in parallel computing, I am by no means an expert in this field, and I suggest you read some of the other excellent posts in this thread to hear from the real experts.
  • Hrmmm... What about Neons, Focuses, and similar cars? Hell, Ford makes & sells cars in Europe that we never get to have on this side of the Atlantic.

  • The problem is that each particle's position needs to be sent to all the other nodes for them to do their calculations. So taking your assumption that each particle takes 34 bytes and assuming the simulation has a million particles in it, you need to send at least 34 MB of data through the network after each calculation. So assuming the calculation takes a while, say 10,000 clock cycles (on a 500Mhz machine) then you need to do 50,000 updates a second. This comes out to about 1,700,000 MB/s of bandwidth. Even if the calculation takes 1,000,000 clocks, you still need at least 17GB/s bandwidth. A beowulf cluster may have a 1 Gb/s bandwidth over gigabit ether but that leaves you short by a factor of 136.

    Using a beowulf for the example above means you can only do 30 calculations per second even though you could theoretically do 500 to 50,000 depending on the amount of clocks the calculation takes.

    Now suppose you had a supercomputer that had a bandwidth of 10GB/s (gigabyte/s). Then you could do about 300 calculations per second even if your processors were running at 300MHZ instead of 500MHz. In cases like this, the I/O bandwidth determines how fast the simulation will go and a beowulf cluster would not be better.

  • If you can overclock a 366 celeron to 550, as was demonstrated on slashdot a while back, without flaws in calculations, then it would only need to survive 2/3 the time to get the same amount of computation out of it.

    The problem is that you won't be sure if it screwed up on a calculation or not, especially since you don't know before hand what the results are supposed to look like. Suppose the result was off by a factor of .001%. Although it may look harmless, the error propagated through a 1000 iteration may result in a large final error. So the software says that a certain configuration of plutonium won't explode when it really will or the simulation predicts the wrong trajectory for a hurricane. In other words, most people would prefer spending an extra million or waiting a few more hours/days to get the correct result.

  • The web page says nothing about nuclear simulations. Its a few molecular dynamics/astrophysics/pde applications.

  • There is a big difference between a cluster of workstations and real supercomputers.
    Nope. Really. The only reasons that the two scale differently are bus speed and software support.

    On the bus speed count, we've got bonded Gb Ethernet. Try 4 bonded, switched 1Gb/s ethernets on for size, and tell me that it's slow. I don't think so, but if you feel it is, there's always fiberchannel.

    Software support is comming. Things like Cluster City and the new SGI boxes will help.

    As a matter of fact, there are many ways in which a single "supercomputer" just isn't super enough. For example, you can take advantage of the fact that you have video on all of those nodes, using the video hardware to do complex calculations that can be simulated in the 3D hardware while the processor does something else. This is tricky, and requires a lot of special-case coding, but there are very large gains to be had.

    There is a reason that such arrays are not as useful as supercomputers for certain purposes, though. This is the fact that most of the people who know how to code for those special purposes are used to mainframes and supercomputers. They are not used to small-node arrays. That will change.
  • You break the problem up, and solve parts of it. *Then* figure out the parts that inter-relate.

    In the case of the above, you also need to take into consideration that you could simply have the math equations needed sent to the cluster, with one primary machine just putting it all together. Example:

    10 to the 10th can be thrown accross 5 machines, calculating 10 to the second. This a very simplistic example, and in real life, wouldn;t work quite right, but in the case of very math intensive applications, some of the equations *can* scale to that extent. It is also able to be processed in parallel, simply becouse you can be working on several equations at the same time.
  • I still cannot understand why all Americans are driving farmer's vehicles (pickups).

    What europeans never realize is that our only currency is hay. Therefore, everyone must drive around a pickup truck filled with bales of hay. It's kind of like a wallet.

    Obviously, there is no use for a pickup truck other than hauling hay bales around. All other large objects are transported by catapult.

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