Slashdot Mirror
Simulating the Universe with a zBox
An anonymous reader writes "Scientists at the University of Zurich predict that our galaxy is filled with a quadrillion clouds of dark matter with the mass of the Earth and size of the
solar system. The results in this weeks journal Nature, also covered in Astronomy magazine, were made using a six month calculation on hundreds of processors of a self-built supercomputer, the zBox. This novel machine is a high density cube of processors cooled by a central airflow system. I like the initial back of an envelope design. Apparently, one of these ghostly dark matter haloes passes through the solar system every few thousand years leaving a trail of high energy gamma ray photons."
Looks like MS will need to come up with a new name for the Xbox 3.
At the center of the box is a small piece of fairy cake
If people can't predict the weather reliably, how on earth is anyone able to predict anything about the way the universe operates?
This looks like the processor set up for the new pentium mentioned in an earlier article. This sucker uses more power than my house!
Frylock: "We should have cloned twenties, Jackson wouldn't have given a fuck."
zBox has been slashdotted, vat do ve do now? Ve relax and eat some cheese and chocolate, jawohl!
[Picture of loads a wires in what looks like a thousand desktops interlinked]
Our in-house designed (Joachim Stadel & Ben Moore 2003), massively parallel supercomputer for running our cosmological N-body simulations. This machine consists of 288 AMD Athlon-MP 2200+ (1.8 GHz) CPUs within a few cubic meters. Under load it produces about 45 kW of heat, about equivalent to 45 electric hair dryers operating continuously! This amount of heat, combined with the extremely high density necessitated a new design for efficient cooling. The 144 nodes (2 CPUs per node) are connected using an SCI fast interconnect supplied by Dolphin in a 12x12 2-dimensional torus. The layout of the machine is ring-like, thereby allowing very short "ribbon" cables to be used between the nodes. This fast interconnect network attains a peak bisection bandwidth of 96 Gbits/sec, with a node-node write/read latency as low as 1.5/3.5 microseconds. Additionally the zBox has 11.5 TBytes of disk (80 GBytes/node) and 3 Gbits/s I/O bandwidth to a frontend server with 7 TB of RAID-5 storage. This is among the fastest parallel computers in the world! At "first light" it ranked in the top 100, but the technology advances quickly. (see top500, June 2003: Rank 144) (see top500, November 2003: Rank 276)
We greatly acknowledge the aid of the Physics Mechanical Workshop at the University of Zurich for: 1) turning the "napkin-sketch" into a proper CAD/CAM design of the machine; 2) providing numerous suggestions which improved the detailed design; 3) providing a gigantic room for the construction of the boards; 4) and, well, building the thing! We thank the companies of Dolphin (dolphinics.com) for supplying the high speed network and COBOLT Netservices for supplying the majority of parts. We would like to especially thank the individuals: Doug Potter and Simen Timian Thoresen for their great help in setting up the linux kernel and root file system, getting netbooting to work correctly, and resolving several operating system related problems. Finally we thank all who helped in the construction of the zBox (assembly of boards, etc), Tracy Ewen, Juerg Diemand, Chiara Mastropietro, Tobias Kaufman
...you just slashdotted Switzerland. Who's next, tough guy? Andorra?
Chip H.
You can read the entire paper in PDF or PS at astro-ph, a web site which collects preprints in the physical sciences. See
http://xxx.lanl.gov/abs/astro-ph/0501589
I read the paper quickly. The authors have to come up with a model which has virtually no observable consequences (otherwise, we would have seen this source of matter by now), but which can also be tested experimentally in the not-too-distant-future (or else it wouldn't be science). They predict that some of the cosmic-ray shower telescopes may be able to detect the little cloudlets of dark matter. We'll see.
Michael Richmond "This is the heart that broke my finger."
mwrsps@rit.edu http://stupendous.rit.edu
So one of these dark matter clouds may pass through the solar system every few thousand years? Have they taken the next step and hypothesized that such an event could account for major climate changes? Like the event that killed off the dinosaurs?
Or maybe they could use that supercomputer to calculate how much fuel it would take to launch these dreaded things into the sun.
Well... it's just a thought.
Ehta nyeh IBM, ehta Macintosh!
http://krone.physik.unizh.ch/~stadel/zBox/story.ht ml
The 3D temperature monitor is really cool.
Maybe they should have use the zbox to host their site =)
i k.unizh.ch/~stadel/zBox/
http://rufus.hackish.org/~rufus/mirror/krone.phys
All it keeps saying is 42...42...42...42...
You can legislate morally you can't legislate morality
... does it run SkyOS?
but then I read in the article:
"and had sufficient forced air through the heat exchangers to transport the heat from a small car out of this small room."
Suprising.
There's nothing Intelligent about Intelligent Design.
Astronomers from Tacoma to Vladivostok have just reported an ionic disturbance in the vicinity of the Van Allen Belt. Scientists are recommending that necessary precautions be taken.
me fail english? thats unpossible
The reason I'm interested is that a non-neutral charge distribution would tend to attract the outer part of the galaxy towards the centre more than would be expected from gravity alone, which is (simplistically) the evidence for dark matter / energy.
"All 288 CPUs shipped by AMD worked perfectly and none needed to be replaced" My 500Mhz AMD works perfectly... as long as I use reliable software (Linux) not that other product - what's it called again... XPee?
Imagine a beowulf cluster of these things!
I'm glad to see some folks still doing things the old fashioned way, even if it was a couple years ago. One question that I have, if anyone is familiar with zBox. Why not go with 2 or 3 racks packed with commercial 1u 2CPU nodes? Was it cost, Heating/cooling? Perhaps it just wouldn't of had that "this is cool shit" factor...
how would this perform with new 2.6 linux kernel ..
the one they are using seems pretty old suse distribution
We are always correct.. even when we realize we were wrong.
I actually thought myself a few months ago about putting a group of 4 HDs and 4 mobos on a large aluminium plate, placing in a wide, flat enclosure and feeding air in at the center and out via 4 peripheral ducts to build a 4-way unit that could sit under a set of office desks arranged roughly in a square. The benefit is that the hardware takes up zero usable desk space, is well protected from physical damage, and the under-desk air flow results in low noise. For high density offices (e.g. call centers) with all power and network connections feeding in to the center of the desk clusters, this could be a very efficient arrangement. It's nice to know I was beaten to it by a Swiss supercomputer.
Panurge has posted for the last time. Thanks for the positive moderations.
You guys are screwed.
From now on, I'm carrying a scorpion in my pocket!
MUAHAHAHAHA
If you don't know what AltaVista is (was), get off my lawn.
If the computer ran for 6 months straight using 1.8GHz processors, couldn't they have waited several months and utilized newer CPUs running at double the speed, halving the computation time?
Regarding their design, I'm somewhat surprised they used an individual power supply for each board. It seems there would be more efficient and smaller power systems available that could power multiple boards at once. It looks like a quarter of the volume of the computer is comprised of power supplies. Plus all that extra heat is thrown into the mix too.
Dan East
Better known as 318230.
and how exactly is the definition of gravity over very long distances different? if it is, could that mean that perhaps there is some other force that is active in deep space that we do not know about because gravity is so strong here near the center of a well?
forces do not just change behavior, when there is a change in behavior it is usually due to another force expressing itself.
I am the Alpha and the Omega-3
Everyone, take a look at those pictures. No, not of the results, but of the computer itself. The page goes over how they built the thing, with pictures of assembling the nodes, the frame, and the completed box. That's a sight to see, all the internal guts forming that piece of computing power.
a self-built supercomputer
I thought we where years away from having to defend ourselves against the machines...
Thats alot of porn!
http://www.livejournal.com/users/cixel
If you were trying to predict rain in the next six months it would be a lot easier than predicting it with any real useful accuracy.
It's the difference between saying it does rain, and when it will. On this scale they are just explaining a phenomena that can happen every so often, in a stellar sense. I'm guessing this eases the difficulty of computation from what would be necessary to predict the number of years before the next occurrence.
Of blankness, I know nothing.
I guess this explains Abu Grahib.
Is SCSI P2P used in real world clusters though? How does it compare to SCI or gigabit ethernet? Price? Performance? Status of the project? No idea...
bundaegi is good for you
While finding nearby moving compact sources of gamma rays might be a way to find these things, another possibility is to look for smaller objects. For example, looking for seismograph records of the passage of a dark matter body through the Earth. Here, the Moon probably is better despite its smaller cross section area since it already has proven to be very quiet seismically.
there's probably a a cancelled CBS comedy.
You can hold down the "B" button for continuous firing.
Shhhh... Don't Say that, The Physicists will lose their funding!
Pie, A magical delicetessant!
Scientists at the University of Zurich predict that our galaxy is filled with a quadrillion clouds of boobies with the mass of the Earth and size of the solar system. I like this solar system.
These aren't the sigs you're looking for.
Actually, where's my BOINC-ready space heater appliance?
Someone had to do it.
Whether the ions in the solar wind worked as an attractive force towards the rest of the galaxy would depend on whether they had enough energy to move out that far. If they had enough energy, then at least that would give me an opening to advocate pushing gravity again, which by the way is also a cool thing to simulate on a zBox.
I'm still trying to figure out what people mean by 'social skills' here.
There's a really impressive simulation, at the Hayden Planetarium ("Rose" something to the kids) in NYC, of a zoom-out from the planetarium, through the Solar System, the Milky Way, local groups, etc, to the "big picture": the entire 15B light-years of the known galaxy, with its weird stringy structures. It's generated from a 4D color model, projected inside the theater's dome, for a breathtakingly convincing ride.
But it lasts only 30 minutes, and has Tom Hanks narrating over the otherwise superb soundsystem. I'd love to get the model and a renderer for my PC. I want to drive around, mix my own soundtrack, maybe pave a few planets in a 3D studio. I'm sure public money paid for the data, and probably the construction of the model. How do we get our copy?
--
make install -not war
Could someone explain why these clouds are postulated to be not only dark, but made out of an exotic new particle? Why can't they be clouds of hydrogen? You know... something normal. I can guess, but maybe a physicist would care to respond?
The biggest reason for the design is the node interconnect speed. From the article:
Commercial racks could not be hooked up that way, at least not without a real cabling mess at the very least, and at the cost of higher latency because of longer cable lengths.
The bandwidth and latency figures quoted above are part of what makes this machine one of the fastest supercomputers of its time.
The tech is pretty cool, but I wonder if all they're doing with it is calculating modern-day epicycles.
If the calculations are correct, then Dark Matter accounts for more mass than any single element in the universe, and has and is reacted on by gravity. There should be some of it close by to take a look at... there should be a good deal of it here on earth, as both earth and dark matter have gravity.
I half-suspect that both dark energy and dark matter are unexpected aspects of gravity working are cosmic scales, but I don't understand the deep geek physics enough to really comment apart from the obvious:
The existance of something so prevalent should be easily proven by direct observation. It hasn't.
SoupIsGood Food
How can you simulate the universe without knowing enought about it. There's still undiscovored planets and other objects which could change significantly the simulation. These unknown variables will cause inaccurate results.
When men were men and supercomputers were really super. It used to take a real genius, like Seymour Cray, to design a computer that could be called "super". A bunch of PC's in a custom case just doesn't do it for me.
...it's a cold day in hell when a scientist finds himself with funding for the pursuit of whimsical what-ifs.
I am yet another practicing scientist and most assuredly find the philosophy of science interesting. I realize a single profession of interest does not make for a good opposing argument and if my kind is really such a minority, perhaps we should question our scientific integrity. However, I do wonder about where you draw the line between useful and pointless inquiry. While direct observation is the only means of validating theory, theorizing before means of observation are available is not a useless endeavor. I doubt anyone would elect to construct a gravitational wave detector or particle accelerator just for shits and giggles.
"I know I haven't been on my best behavior the past decade" -Some bit of dialogue from "The Life Aquatic"
And, in Asimov's story "The Last Question," the Big Crunch produced the Big Bang.