archiv~1.txt: Re: SETI-L: Everybody may be afraid & a Answer

Re: SETI-L: Everybody may be afraid & a Answer
Sat, 27 Mar 1999 12:18:18 -0600 (EST)

I could easily understand them doing multiple gigabytes of data, in a few
hours. I'm sure they have the equipment to do that. I never said that
they lied, I am just suggesting that maybe they were wrong, but not

On Sat, 27 Mar 1999, David Woolley wrote:

> > accumulate 15 terabytes of data. I don't know how many of you are
> > computer professionals, or even know that much about computers, but that
> > is an extremely ludicrous number. They said all processing is done in
> You are assuming general purpose computers, whereas this will be a special
> purpose FFT machine.
> > realtime. If you can show me a computer that can process 15 terabytes of
> > information into complex search algorithms in the short time they spend to
> The bulk processing will use simple algorithms and any complex algorithms
> will be applied to interesting signals. This is a standard tactic for
> efficient searching - reduce the problem by using a simple filter first.
> > btw, I've used beowulf clusters on 1terabyte raid systems, and it has
> > taken WEEKS to do certain things. I'm sure the seti algorithms are
> > equally complex.
> I think you are thinking of disk limited systems; the bulk processing will
> only be performed on a small window of the data, and as said above,
> the bulk of the data will only have simple algorithms applied.
> 5TB really isn't that difficult to capture. If you are scanning a 500MHz
> window, at 4 bits per sample, it only takes about 3 hours of raw data.
> Incidentally, SETI League members don't seem to publish raw data either;
> you simply get the result of applying an FFT and integrating.
> I think it is fairly safe to assume that a respectable organisation
> may be economical with the truth (not mention the competition, for example,
> or rely on people thinking in terms of general purpose computers) but
> would never deliberately lie. Tera Bytes is not an everyday term, so it
> also unlikely to have been used by mistake.