Slashdot Mirror
Three-Mile-High Supercomputer Poses Unique Challenges
Nerval's Lobster writes "Building and operating a supercomputer at more than three miles above sea level poses some unique problems, the designers of the recently installed Atacama Large Millimeter/submillimeter Array (ALMA) Correlator discovered. The ALMA computer serves as the brains behind the ALMA astronomical telescope, a partnership between Europe, North American, and South American agencies. It's the largest such project in existence. Based high in the Andes mountains in northern Chile, the telescope includes an array of 66 dish-shaped antennas in two groups. The telescope correlator's 134 million processors continually combine and compare faint celestial signals received by the antennas in the ALMA array, which are separated by up to 16 kilometers, enabling the antennas to work together as a single, enormous telescope, according to Space Daily. The extreme high altitude makes it nearly impossible to maintain on-site support staff for significant lengths of time, with ALMA reporting that human intervention will be kept to an absolute minimum. Data acquired via the array is archived at a lower-altitude support site. The altitude also limited the construction crew's ability to actually build the thing, requiring 20 weeks of human effort just to unpack and install it."
Simple answer: Have redundancy all over the place so it doesn't matter if a few modules fail. The repair crew can go in once a year and swap them.
No sig today...
Drove three of my friends over Tioga Pass in the Sierra Nevada's in the north of Yosemite...couple of them had never been out of Louisiana...between 8000 and the summit of the pass at ~10,000 ft meant me driving while everyone else suffered from altitude sickness...the only cure is to remove to a lower elevation. Having grown up in the sierras, i was used to the elevation...but if you're not acclimated, then you're going to walk 20 feet and have to sit down to rest for 10 minutes.
There are three kinds of people in the world. Those that can count, and those that can't.
134 million processors, 140 kilowatts?!?
1 miliwat per processor?
More than one fiber would be needed. There are 50 antennas each with multiple fibers connected to the correlator. A lot of thought went into it and despite the complications it was simpler to put the correlator there than 'down the road'.
Mis-interpreted the article title and though that someone was building a supercomputer that is three miles tall. I bet that poses unique challenges too.
The hard drives don't belong at that altitude, then. The correlators can well be completely diskless machines, even without a solid state drive. They can boot over the network from the lower-altitude server station.
A successful API design takes a mixture of software design and pedagogy.
That's exactly what I thought.
"A three mile tall supercomputer? You're damned right that poses some unique challenges!"
The Internet King? I wonder if he could provide faster nudity.
This is ridiculous. Just pressurize the server room or whole building and be done with it. That layer of air would automagically reappear for the heads to glide over the platters.
As for particles, I know nothing about the subject but I guess that mountain isn't much closer than we are from the particle sources. I do not think the additional layer of atmosphere said particles have to go through to get to us makes a difference.
My understanding is that particles are deviated at higher altitude than mountains by the Earth magnetic field.
Everything I write is lies, read between the lines.
Any discussion in TFA about why they aren't just sending that data over optical cables to wherever would make sense to house a data-center? e.g. ground-level?
Why does it need to be so near the array?
Speed of signal over fibre can't be the difference (i.e. what difference does 1 km or 40km make? not much).
The far side of the Moon. No clouds, no rain, and only a little bit of dust every so often.
At that altitude, the pressure is about half that of sea level. So to pressurize the building, you would have to do so by several psi to bring it down to something a little lower.
well, 1/2 atmosphere = 7 psi.
5 psi should be enough,
8 psi causes stress on en airplane fuselage but planes have to be light. Submarines can stand 1,500 psi and above...
My point is that it just might end up being cheaper than fixing/adapting every piece of equipment individually, in a never ending quest. Who know?
Everything I write is lies, read between the lines.
They are combining signals from dishes separated by up to 16km so it is not a necessity that the supercomputer be right next to one of the dishes. Why not build the supercomputer at the base of the mountain instead of the top. They are already beaming raw data around so it will not make a difference.
Just virtualize the supercomputer in the clouds and put the virtual machine on the mountain!
See?
Defining Statistics and Social Research
Of course that means that the room pressurization would be a single point of failure for every hard drive you had. Lose pressure and every drive suffers a head crash simultaneously... Oops.
If I didn't need the storage volume I'd certainly prefer drives like SSDs that didn't require pressurization to work at that altitude. One less thing to go wrong. (Although the ability to pressurize the building when necessary to make maintenance / upgrades easier on the IT guys would be cool and useful)