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Exceptional Seeing At Dome C in Antarctica
Michael Ashley writes "A paper published in Nature
today reports on the exceptional
astronomical seeing conditions at Dome C (Coral link)
in Antarctica. Obtaining the data posed some significant technological
challenges, given that Dome C is uninhabited over winter. The
experiment was controlled by a PC/104
computer system that had to survive temperatures down to -85C, and
supervise the generation of its own electricity using a jet-fuel
powered stirling engine. The computer, running Linux, communicated with
the outside world using an Iridium
phone. The results are also covered in New
Scientist, and the Sydney
Morning Herald. Disclaimer: I'm a co-author."
Look at this photo. It is the author's Kyocera mobile phone with a web page showing the temperatures, memory usage and free disk space. Says battery temperature is -34.5 (is that C or F?)
2bits.com, Inc: Drupal, WordPress, and LAMP performance tuning.
What is "seeing"?
"Seeing" is a term that astronomers use to quantify the turbulence in the atmosphere and how it affects observations from the ground. The stars appear to twinkle because of the effect of this turbulence. In conditions of bad seeing, the stars appear to twinkle vigorously, and the images that you take with your telescope are blurry. In conditions of good seeing, the stars appear more stable, and you can take very sharp images.
You'd think they'd have a cooler word for that...
The link that the submitter provided to himself doesn't work. The correct link is: Michael Ashley
A PC/104 is just a form factor. And provides standards for things such as environmental operating parameters.
CPU boards usually have an intel clone processor MACH86 or VIA Athena.
So they can run any OS your desktop can.
Harder.. Better.. Faster.. Stronger
While colder can often mean faster, sometimes a signal requires some minimum delay to work correctly. This is especially true of the minimum hold times required on inputs after a clock transition. So it's possible that some signal might go out of spec if you drop the temperature too far. It only takes a single bad signal to hose the whole system.
Unlike just dropping the temperature of the CPU chip which will have relatively uniform characteristics, getting the whole system cold might cause a wider range of timing variations. Moreover, even dropping the external heat sink of a CPU to extreme cold doesn't mean the chip itself is in the cryogenic range. They usually run at temps well above the bulk of the heatsink.
Just stick .nyud.net:8090 on the end of your domain name (before the /) and it'll grab the content and cache it -- any future queries will return their cache instead of downloading from the original page. The coral links also work like your web browser and update the content when it is out of date.
Dude, I used to live in Alaska. The solution to the tongue problem, at least according to the neighborhood experts, is to urinate on it until it gets unstuck.
BTM
That was the turning point of my life--I went from negative zero to positive zero.
Computing equipment *loves* cold, as long as you don't have to worry about condensation.
Ah, not so! *processor cores* love cold, not electronics in general. Specifically, electrolytic capacitors freeze and fail below their rated temperature, and it's really tough to find any that are rated to temps that low. Also, because of resistance, capacitance, and crystal frequency value changes at low temps, oscillators and filters tend not to behave. This doesn't even consider the issue of thermal expansion coefficient differences causing BGA chips to pop off the circuit boards! Making anything electronic operate in that environment is highly non-trivial.
I am a geek attorney, but not your geek attorney unless you've already retained me. This is not legal advice.
The CPU is called the VIA C3 and the chipset is the VIA Eden. The "Athena" in your post refers to a Diamond Systems product name for the board which uses this CPU, not the name VIA calls their own CPU.
;-)
The "Mach86" you're thinking of is the ZFMicro ZFx86 chip. They are battling National Semiconductor, who produced these CPUs under contract for ZFMicro until ZFMicro was no longer able to pay their bills. Intel is not involved at all.
The other big PC/104 CPU vendors are Transmeta, STMicro (STPC), and AMD (Geode). Recently the Pentium 4-M have been popular for boards which don't need to support extended temperature.
PC/104 rocks for applications like this. Disclaimer: I work for a PC/104 company.