I remember..

I remember the thrill of when I first got involved in the SETI@home search. Back then I worked in a lab with three computers with just one of them connected to the internet. Each day, the first thing I would do was to pick up a 3.5" floppy and collect the work unit that had completed over night from each the unconnected machines and copy it across to the connected machine. I'd upload it and then download a fresh unit ready to run for the next 24 hours, so using the combined power of three top end computers I was crunching through a massive 3 units a day for 5 days a week. But of course things have moved on just a bit since then.
Since then, the amount of science done per wu has increased dramatically but the effect of Moore's Law has also been dramatic. My current machine which is now crunching with its graphics card as well as its multi-core cpu looks to be whizzing through wus at a rate of around 260 per day - a massive increase in throughput over the last decade.
Then I look at the server status page and see the incredible power of the combined SETI farm processing work units at the astounding rate of 47000 per hour which is an incredible search rate.
But hang on a minute.. according to the How SETI@home Works page Arecibo collects around 35Gb of data per day.
That data splits into 0.25Mb work units equating to around 140,000 units per day. With each unit having to be sent out at least twice that brings us to 280,000 per day. I don't know what the failure rate is, but lets say that it is as high as 50% then we are up to 420,000 units for each day's raw data collection.
That is 17,500 work units per hour to keep up with the real time data collection rate. Am I missing something here? If not, then we must be working through a backlog of raw data at a very respectable rate and at some point we will clearly reach a limit of 17,500 units per hour leaving much of our processing capacity unused.
Moore's Law is not going to stop any time soon, perhaps it is time to think again about the science that can be done or perhaps unload some of the effort being done on the server side out into the community?
Are my maths wrong or is the project massively over served by volunteer processing and if it is, what can be done with all this left over computing power?
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In other words the rate at which work can be created will be the weak link in the chain...

When CPUs/GPUs become idle they will therefore move over to other DC projects :).

Amazing isn't it. Personally, I hope that other software processing issue besides the Fast Fourier would be refined, such as the spectrum analysizers like the US Navy have in isolating discreet frequencies.

Dr Gray in my college days I also had a great fasination for SETI and still do. I helped out at the college computer lab had 37 computers running 24-7. I dont remember how much we processed but I lost all that information from the college. Im thinking we just arent in the ball park with detecting signals. I would expect some type of burst communication because of the distances involved. Most information at the fastest transmission. I wonder if in fact sometime in microwave bandwidth would work over great distance. Either that or ultralow frequencies. We are examining the middle.

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Jason on the other hand had the brilliant idea to split data on the client side: Since the raw data for Astropulse and Multibeam is the same, why not transmit the 8MB only once, then use it 1) for Astropulse and 2) for Multibeam (split into n pices by the client computer).

Dr Gray in my college days I also had a great fasination for SETI and still do. I helped out at the college computer lab had 37 computers running 24-7. I dont remember how much we processed but I lost all that information from the college. Im thinking we just arent in the ball park with detecting signals. I would expect some type of burst communication because of the distances involved. Most information at the fastest transmission. I wonder if in fact sometime in microwave bandwidth would work over great distance. Either that or ultralow frequencies. We are examining the middle.

Due to planetary rotations and orbits, I would think no signal would be constant, but eventually repeating. So if we get 2 hits out of several hundred or thousand with a good gaussian, I think we got something of major interest.


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Janice

Good questions--I would like a crisp definition of how we are revisiting promising results. I know that ARECIBO does not lend itself to doing this conveniently.

I am also curious why the Allen Array doesn't use BOINC--internacine warfare inhibiting our chances of success ??

You tell me.

Daddio

From am article in "Nature" magazine of 16 September 2009 I have learned that the ATA has 3 users: the US Air Force, which covers its operating costs, the SETI Institute and the UCB Astronomy Dept. through its Radioastronomy Lab. The first in not interested in ETI, the second has its own project, Setiquest (see www.setiquest.org). Why the third is not cooperating with the Space Sciences Laboratory which manages SETI@home is a question I am not able to answer.
Tullio
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