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[FAQ] Seti@home Frequently Asked Questions

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Archive-name: seti/at-home/questions
Posting-Frequency: Monthly
Last-modified: 09 November 2003
Version: 3.0.10
Copyright: (c) 1999-2002 Mark Taylor, Alfred Das
Maintainer: Mark Taylor <>

See reader questions & answers on this topic! - Help others by sharing your knowledge
SETI@home FAQ V3.0.10 09 November 2003

for newsgroups alt.sci.seti and sci.astro.seti

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Author       :Mark Taylor <>
Html-version :Alfred Das <>

Contributors :SETI@home team, Peter Alfredsen, Frank J. Perricone,
              M. Stilgar, Arthur Schain, Ed H, Neil Rieck,
              Thomas Martin, Malcolm Pack, James Birchfield,
              Roelof Engelbrecht, Allen Cleveland, Chris Johnson,
              Carl Sagan, Eric J. Korpela, Terry Lee, Sqiz,
              David Woolley, Jan Knutar, Peter van der Kort,
              David Schilling, Alfred Das, Peter Yackel, Lior Fainshil,
              Eric Heien, John Pike, Steve Willner,Alfred A. Aburto Jr.

--- Comments from the Author ---

Don't hesitate to contact me if you see something in the FAQ that you
think is wrong. Suggestions, comments, additions, corrections, etc are
more than welcomed. I'll reply to every email so that you'll know if
your addition/correction will be included and if not, why. People who
contribute to the FAQ will be given credit if they wish so. This latest
version of the FAQ increases to version 3.0.0 to match the current major
version of the Seti@home Client.


Mark Taylor <>

--- Comments from the Author ---

--- Legal Chit-chat ---

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--- Legal Chit-chat ---

0      INDEX

1      About SETI@home

1.1    What is SETI@home?

1.2    Background
1.2.1  The Drake Equation
1.2.2  The Fermi paradox
1.2.3  How far away could we detect radio transmissions?
1.2.5  Setup of the SETI@home project
1.2.6  What is a Gaussian?
1.2.7  Analysis of the end data from the SETI@home project
1.2.8  What are pulses and triplets?

1.3    The history and customs of alt.sci.seti and sci.astro
1.3.1  Charter for alt.sci.seti
1.3.2  Charter for sci.astro.seti
1.3.3  Naming convention
1.3.4  .sig convention
1.3.5  Labeling posts
1.3.6  Patching or cracking SETI@home
1.3.7  What is a 'vcard' and why do people tell me not to use them?
1.3.8  What is PST and PDT?

1.4    What will happen if an extraterrestrial signal is detected?
1.5    How is data collected from the telescope and transmitted to
       other machines for analysis?
1.6    Are earth signals strong enough to be detected?
1.7    What if my computer finds a signal -- how will I know?
1.8    How can I hear the signal?
1.9    Is there something in it for me?
1.10   Why doesn't SETI@home release the sources for the clients?

2      Problems and questions concerning SETI@home

2.1    Speed improvements
2.1.1  What's the fastest computer to use for this project?
2.1.2  Can I make it run any faster?
2.1.3  REMOVED March 2000, was:
       Can I run the SETI@home text-client on Win95?
2.1.4  Will SETI@home run faster with more RAM (e.g., 256 MB instead of
       128 MB)?

2.2    REMOVED April 2000, was:
       I'm using a proxy server, and I can't connect - what do I do?
2.3    I had a work unit that got returned after only 5 minutes. What's
2.4    I heard I was getting the same work unit as everyone else. Is
       the program wasting my time?
2.5    My computer wanted to upload to the SETI@home server but said it
       couldn't connect or reported error 10065. Are they still there?
2.6    What if someone fakes a result to make it seem like they found a
2.7    SETI@home keeps getting a 'Bad Header' error. What can I do?
2.8    Suddenly, without warning my system crashes - what should I do?
2.9    I can't see the new WU's I've processed in the status area. Have
       they been registered at SETI@home?
2.10   I want to run the text-client as a service in NT - how do I do
2.11   Can I run the client invisibly on Win95/98?
2.12   Sometimes the size of the workunit.txt file differs in size.
       Sometimes it's 340, sometimes 341, and yet other times 351. Is
       there something wrong?
2.13   I don't have a permanent Internet connection, and have to pay
       for all my phone calls and net usage. Can I run SETI@home
       without going bankrupt?
2.14   I already run the RC5-64 client. Can I run
       SETI@home as well, or do I have to choose which project to
2.15   What happened to the gaussian information display in the new Mac
       and Windows clients? The client is finding gaussians with lower
       fits, do the 2.x clients find more aliens or something?
2.16   Can I run SETI@home 24/7 if I don't have a permanent Internet
2.17   Is this bad for my processor, or my harddrive?
2.18   Does it use up a lot of electricity? Is this costing me money,
       or doing damage to the environment?
2.19   How can I keep appraised of what's going on lately?

2.20   General CL client issues
2.20.1 What is the CL client?
2.20.2 What CL options are there?
2.20.3 HELP, it stops at baseline smoothing!!!
2.20.4 How can I check up on the client to see how it's doing, if it
       has found any signals, etc?
2.20.5 How do I tell the CL client to use a proxy?
2.20.6 I just found a bug in the -stop_after_ switches!!!

2.21   Running the CL client on Windows
2.21.1 What client should I download for Windows 95/98/2000/NT?
2.21.2 How do I start it?
2.21.3 How do I stop it?
2.21.4 How do I make Windows 2000 autoconnect?
2.21.5 Do I have to uninstall the screen saver version if I use the CL

2.22   A short guide for the Linux newbie trying to run the SETI@home
2.22.1 What client should I download?
2.22.2 How do I uncompress the .tar file?
2.22.3 How do I start it?
2.22.4 How do I stop it?
2.22.5 How can I run it in the background rather than in a window?
2.22.6 How can I have it automatically restart if it dies?
2.22.7 What is 'nice' and how do I set it?

2.23   Why does the client timeout before windows has dialed up my ISP?
2.24   I just got a gaussian with a score of 0.50 and power 1.2, is
       this good?
2.25   I looked at my stats of returned units at SETI@home's webpage,
       the top gaussian I got for the last unit is missing, why?
2.26   My email address is about to change, what do I do?
2.27   Re-ordered to 2.30 (10-5-2000)
2.28   Why does the new client (3.X) take more time to complete a WU?
2.29   What are pulses and triplets?
2.30   What is an interesting pulse/triplet?
2.31   Why do certain WU's take longer to process?
2.32   Why are the most pulse searches done at a chirp rate of 0?
2.33   There's something strange with the power reported on pulses in
       outfile.sah vs. state.sah?
2.34   Is the first half of the pulse graph identical to the second?

3      Third-party software

3.1    JSETITracker
3.1.1  Programmer's comments

3.2    Tk-SETI@home
3.2.1  Programmer's comments
3.2.2  Tk-SETI@home installation
3.2.3  Tk-SETI@home startup

3.3    SETI Spy
3.3.1  Programmer's comments
3.3.2  Processing efficiency

3.4    SETIWatch
3.4.1  What is SETIWatch?
3.4.2  Some background
3.4.3  Where can I get it?
3.4.4  How to install SETIWatch

3.5    SETILog
3.5.1  What is SETILog?
3.5.2  How does SETILog work?
3.5.3  RunSETI.bat
3.5.4  Where can I get it?
3.5.5  How to Install SETILog

3.6    SetiTEAM
3.6.1  Description

3.7    SETIBuf
3.7.1  Legal notice and stuff
3.7.2  General description
3.7.3  Where can I get it?

3.8    SETI Monitor
3.8.1  Description
3.8.2  Some more details
3.8.3  Where can I get it?

3.9    SETI UniT Manager
3.9.1  About SUM
3.9.2  Cost
3.9.3  Requirements
3.9.4  Where can I get it?

3.10   Setimgr
3.10.1 Prgrammer's comments
3.10.2 Setup
3.10.3 Operation
3.11   Seti4Net
3.12   Multi-SETI@home Monitor - Msetimon

4      Homepages

4.1    Homepages concerning SETI@home
4.1.1  SETI@home home
4.1.2  SETIweb
4.1.3  SETIforum
4.1.4  SETI @ SixDegrees
4.1.5  SETI@home Speedup Tips
4.1.6  Derived statistics for SETI@home @ Rovingmouse
4.1.8  SETI: The Drake Equation
4.1.9  Sci.astro FAQ about SETI
4.1.10 Team Canada
4.1.11 The Planetary Society
4.1.12 Patch-free-Processing
4.1.13 Sky & Telescope
4.1.14 SETI Institute
4.1.15 SETI League
4.1.16 Removed 11 Feb 2001 (was SETI & Beyond)

4.2    SETI utilities
4.2.1  SETIwatch & SETIlog
4.2.2  SETI Manager
4.2.3  TKSETI@home
4.2.4  SETISPY
4.2.5  JSETITracker
4.2.6  SetiTEAM Homepage
4.2.7  SETIBuf homepage
4.2.8  SETI Monitor homepage
4.2.9  SETI UNiT Manager homepage
4.2.10 RunCache & FetchCache
4.2.11 Seti@home Service

4.3    SETI fun
4.3.1  Carolyn's Clinic

5      Acknowledgements

5.1    Sci.astro FAQ
5.2    People who have worked with the FAQ


1      About SETI@home

1.1    What is SETI/SETI@home?

       If we assume that our alien neighbors are trying to contact us,
       we should be looking for them. There are currently several
       programs that are now looking for the evidence of life elsewhere
       in the cosmos. Collectively, these programs are called SETI (the
       Search for Extra-Terrestrial Intelligence.) SETI@home is a
       scientific experiment that harnesses the power of hundreds of
       thousands of Internet-connected computers in the Search for
       Extraterrestrial Intelligence (SETI). You can participate by
       running a free program that downloads and analyzes radio
       telescope data. There's a small but captivating possibility that
       your computer will detect the faint murmur of a civilization
       beyond Earth.

1.2    Background

1.2.1  The Drake Equation

       <This is only one possible guess at, how the Drake Equation may
       be. If you want to guess for yourself, look under 4.1.8  SETI:
       The Drake Equation>

       Our sun is only a single star in a collection of over 400 billion
       we call the Milky Way galaxy. The Milky Way is only 1 of billions
       of galaxies in the universe. Seems like there should be lots of
       life out there! Can we make an initial estimate? The first to do
       so was the astronomer Frank Drake. He came up with a simple
       equation, now called the Drake Equation, that maps out the
       possibilities. The equation is quite easy to understand, so don't
       tune out, even if arithmetic isn't your strong suit! Here it is:

       N = R * f(p) * n(e) * f(l) * f(i) * f(c) * L

       "N" here represents the number of communicating civilizations in
          our Milky Way galaxy. This number depends on several factors.
       "R" is the rate of "suitable" star formation in the galaxy.
       "f(p)" is the fraction of stars that have planets.
       "n(e)" is the number of these planets around any star within the
          suitable ecosphere of the star. An "ecosphere" is a shell that
          surrounds a star within which the conditions are suitable for
          life to form. Too close and it's too hot; too far and it's too
       "f(l)" is the fraction of those planets within the ecosphere on
          which life actually evolves.
       "f(i)" is the fraction of those planets on which intelligent life
       "f(c)" is the fraction of those planets where intelligent life
          develops a technology and attempts communication. 
       "L," is the length of time that an intelligent, communicating
          civilization lasts. 

       Let's briefly look at each of these factors separately and try to
       put some reasonable numbers to them. Although the rate of
       suitable star formation was undoubtedly much higher when our
       galaxy formed, one can still see where stars are being born
       today. In the last couple of years, several teams of astronomers
       have announced the discovery of planets surrounding nearby stars.
       This exciting discovery increases the likelihood of other planets
       around many stars. Let's estimate conservatively that one-half of
       the stars form planetary systems; the other half form binary star
       systems, so

       f(p) = 0.5.

       The n(e) factor is a little tricky. Small stars are cool and red.
       Planets would have to orbit very close to be in the ecosphere.
       Also, this ecosphere would be very narrow; like the skin on an
       orange. Not much room for planets. Planets that orbit very close
       to their parent star are often tidally locked and present one
       face to the star at all times. The atmosphere of such a planet
       would freeze on the cool side that faces away from the star; this
       does not promote life. On the other hand, huge hot blue stars
       have a farther and wider ecosphere. Of course, judging from our
       solar system, planets are spaced further apart the farther they
       are from the star, so the wider ecosphere is cancelled by this
       effect. These larger stars also burn their fuel faster and don't
       last very long. They are usually so short- lived that life does
       not even get a chance to start before the star goes nova or
       supernova and destroys everything in the system. In our solar
       system, with our average-sized yellow sun, we have two (Earth and
       Mars) or maybe three (Venus) planets within the ecosphere. A
       conservative guess for the number of planets within the "life
       zone" or ecosphere is one.

       n(e) = 1.

       The next factor, f(l), is where things become a little sticky.
       The problem is that we only have a few examples of planets where
       conditions are right for life to evolve. As stated above, Venus,
       Earth, and Mars all could have had, at one time, proper
       conditions. We know life evolved on Earth, and there is now
       tantalizing evidence for primitive life existing on Mars
       billions of years ago. A conservative guess for this number is
       0.2, or one in five planets with proper conditions will evolve

       f(l) = 0.2.

       How many of these planets will evolve intelligent life? Tough
       question, but if we really believe the evidence for natural
       selection and survival of the fittest, most scientists would put
       this number at 100 percent -- that intelligent life is a natural
       outcome of evolution. Of course, here we have only one example,

       f(i) = 1.

       How many of these intelligent species will develop technology and
       use it to communicate? If we look at the earth, we see humans
       doing it, but we also see whales and dolphins, who may also
       possess a moderate level of intelligence but never developed
       technology. We'll set this number to 0.5 as a first guess.

       f(c) = 0.5.

       Now we get to the hardest number to determine. "L" is the number
       of years that a technologically adept and communicative
       civilization lasts. We've only been in this phase of our
       evolution for about 50 years. Do advanced civilizations blow
       themselves up after discovering the technology to do so? Or do
       they get together and solve their problems before this happens?
       For now, let's not assign a number to L. Let's plug in the other
       numbers and see what we get.

       N = R * f(p) * n(e) * f(l) * f(i) * f(c) * L

       N = 20 * 0.5 * 1 * 0.2 * 1 * 0.5 * L

       Do advanced civilizations use their technology to solve their
       problems or do they destroy themselves? On earth we've survived
       the first 50 years. Multiplying all the numbers gives us N = L.
       In other words, the number of intelligent communicating
       civilizations in the galaxy equals the number of years such a
       civilization lasts! The figure about which we know the least
       bears a great significance in our calculations. Most scientists
       hope that if a civilization can overcome its initial tendency to
       destroy itself with its own technology, then that civilization
       is likely to last for a very long time. Let's hope those
       scientists are right. In any case, there should be at least 50
       (the number of years WE'VE been around communicating) and if a
       communicative civilization lasts for millions of years, there
       may possibly be millions of civilizations we can look for.

1.2.2  The Fermi paradox

       By John Pike and Steve Willner

       One of the problems that the Drake Equation produces is that if
       you take reasonable (some would say optimistic) numbers for
       everything up to the average duration of technological
       civilizations, then you are left with three possibilities:

       1. If such civilizations last a long time, "They" should be
          _here_ (leading either the the Flying Saucer hypothesis--they
          are here and we are seeing them, or the Zoo Hypothesis--they
          are here and are hiding in obedience to the Prime Directive,
          which they observe with far greater fiqdelity than Captain
          Kirk could ever muster). -or-

       2. If such civilizations last a long time, and "They" are not
          "here" then it becomes necessary to explain why each and
          every technological civilization has consistently chosen not
          to build starships.  The first civilization to build
          starships would spread across the entire Galaxy on a
          timescale that is short relative to the age of the Galaxy.
          Perhaps they lose interest in space flight and building
          starships because they are spending all their time surfing
          the net. (Think about it --- the whole point of space flight
          is the proposition that there are privileged spatial
          locations, and the whole point of the net is that physical
          location is more or less irrelevant.)

       3. Such civilizations do not last a long time, and blow
          themselves up or otherwise fall apart pretty quickly
          (... film at 11).

       Thus the Drake Equation produces what is called the Fermi
       Paradox (i.e., "Where are They?"), in that the implications of
       #3 and #2 are not terribly encouraging to some folks, but the
       two flavors of #1 are kinda hard to come to grips with.

       An alternate version of 2 is that interstellar travel is far more
       difficult than we think it is.  Right now, it doesn't seem much
       beyond the boundaries of current technology to launch "generation
       ships," which amount to an O'Neill colony plus propulsion and
       power systems.  An alternative is robot probes with artificial
       intelligence; these don't seem so difficult either.  The Milky
       Way galaxy is well under 10^5 light years in diameter and over
       10^9 years old, so even travel beginning fairly recently in
       Galactic history and proceeding well under the speed of light
       ought to have filled the Galaxy by now.  (Travel very near the
       speed of light still seems very hard, but such high speed isn't
       necessary to fill the Galaxy with life.)  The paradox, then, is
       that we don't observe evidence of anybody besides us.

1.2.3  How far away could we detect radio transmissions?

       By Al Aburto and David Woolley

       Representative results are presented in Tables 1 and 2.  The
       short answer is
       (1) Detection of broadband signals from Earth such as AM radio,
           FM radio, and television picture and sound would be
           extremely difficult even at a fraction of a light-year
           distant from the Sun.  For example, a TV picture having 5
           MHz of bandwidth and 5 MWatts of power could not be detected
           beyond the solar system even with a radio telescope with 100
           times the sensitivity of the 305 meter diameter Arecibo

       (2) Detection of narrowband signals is more resonable out to
           thousands of light-years distance from the Sun depending on
           the transmitter's transmitting power and the receiving
           antenna size.

       (3) Instruments such as the Arecibo radio telescope could detect
           narrowband signals originating thousands of light-years from
           the Sun.

       (4) A well-designed 12 ft diameter amateur radio telescope could
           detect narrowband signals from 1 to 100 light-years distance
           assuming the transmitting power of the transmitter is in the
           terawatt range.

       What follows is a basic example for the estimation of radio and
       microwave detection ranges of interest to SETI.  Minimum signal
       processing is assumed.  For example an FFT can be used in the
       narrowband case and a bandpass filter in the broadband case (with
       center frequency at the right place of course).  In addition it
       is assumed that the bandwidth of the receiver (Br) is constrained
       such that it is greater than or equal to the bandwidth of the
       transmitted signal (Bt) (that is, Br >= Bt).

       Assume a power Pt (watts) in bandwidth Bt (Hz) radiated
       isotropically. At a distance of R (meters), this power will be
       uniformly distributed (reduced) over a sphere of area: 4 * pi *
       R^2. The amount of this power received by an antenna of effective
       area Aer with bandwidth Br (Hz), where Br >= Bt, is therefore:

         Pr = Aer * (Pt / (4 * pi * R^2))

       If the transmitting antenna is directive (that is, most of the
       available power is concentrated into a narrow beam) with power
       gain Gt in the desired direction then:

         Pr = Aer * ((Pt * Gt) / (4 * pi * R^2))

       The antenna gain G (Gt for transmitting antenna) is given by the
       following expression.  (The receiving antenna has a similar
       expression for its gain, but the receiving antenna's gain is not
       used explicitly in the range equation.  Only the effective area,
       Aer, intercepting the radiated energy at range R is required.)

         Gt = Aet * (4 * pi / (w^2)), where

             Aet = effective area of the transmitting antenna (m^2), and
             w = wavelength (m) the antenna is tuned to.
             f = c / w, where f is the frequency and c is the speed of
             c = 2.99792458E+08 (m/sec)
             pi = 3.141592654...

       For an antenna (either transmiting or receiving) with circular

         Ae = <eta> * pi * d^2 / 4

              <eta>r = efficiency of the antenna,
              d = diameter (m) of the antenna.

       The Nyquist noise, Pn, is given by:

         Pn = k * Tsys * Br, where

                 k = Boltzmann's constant = 1.38054E-23 (joule/kelvin)
              Tsys = is the system temperature (kelvins), and
                Br = the receiver bandwidth (hertz).

       The signal-to-noise ratio, snr, is given by:

         snr = Pr / Pn.

       If we average the output for a time t, in order to reduce the
       variance of the noise, then one can improve the snr by a factor
       of sqrt(Br * t). Thus:

         snr = Pr * sqrt(Br * t) / Pn.

       The factor Br*t is called the "time bandwidth product," of the
       receive processing in this case, which we'll designate as:

         twp = Br * t.

       We'll designate the integration or averaging gain as:

         twc = sqrt(twp).

       Integration of the data (which means: twp = Br * t > 1, or
       t > (1 / Br) ) makes sense for unmodulated "CW" signals that are
       relatively stable over time in a relatively stationary (steady)
       noise field.  On the other hand, integration of the data does not
       make sense for time-varying signals since this would distroy the
       information content of the signal.  Thus for a modulated signal
       twp = Br * t = 1 is appropriate.

       In any case the snr can be rewritten as:

       snr = (Pt * Gt) * Aer * twc / (4 * pi * R^2 * Br * k * Tsys)

       Pt * Gt is called the Effective Isotropic Radiated Power (EIRP)
       in the transmitted signal of bandwidth Bt. So:

       EIRP = Pt * Gt, and

       snr = EIRP * Aer * twc / (4 * pi * R^2 * Br * k * Tsys)

       This is a basic equation that one can use to estimate SETI
       detection ranges.

# If Rl is the number of meters in a light year (9.46E+15 [m/LY]),    #
# then the detection range in light years is given by                 #
#                                                                     #
# R = sqrt[ EIRP * Aer * twc / (4 * pi * snr * Br * k * Tsys) ] / Rl  #
#                                                                     #
# If we wanted the range in Astronomical Units then replace Rl        #
# with Ra = 1.496E+11 (m/AU).                                         #

       Note that for maximum detection range (R) one would want the
       transmit power (EIRP), the area of the receive antenna (Aer), and
       the time bandwidth product (twp) to be as big as possible.  In
       addition one would want the snr, the receiver bandwidth (Br), and
       thus transmit signal bandwidth (Bt), and the receive system
       temperature (Tsys) to be as small as possible.

       (There is a minor technical complication here.  Interstellar
       space contains a plasma.  Its effects on a propagating radio wave
       including broadening the bandwidth of the signal.  This effect
       was first calculated by Drake & Helou and later by Cordes &
       Lazio.  The magnitude of the effect is direction, distance, and
       frequency dependent, but for most lines of sight through the
       Milky Way a typical value might be 0.1 Hz at a frequency of 1000
       MHz. Thus, bandwidths much below this value are unnecessary
       because there will be few, if any, signals with narrower

       Now we are in a position to carry out some simple estimates of
       detection range.  These are shown in Table 1 for a variety of
       radio transmitters.  We'll assume the receiver is similar to
       Arecibo, with diameter dr = 305 m and an efficiency of 50%
       (<eta>r = 0.5).  We'll assume snr = 25 is required for detection
       (The META project used a snr of 27--33 and SETI@home uses 22;
       more refined signal processing might yield increased detection
       ranges by a factor of 2 over those shown in the Table 1.)  We'll
       also assume that twp = Br * Tr = 1. An "educated" guess for some
       of the parameter values, Tsys in particular, was taken as
       indicated by the question marks in the table. As a reference note
       that Jupiter is 5.2 AU from the Sun and Pluto 39.4 AU, while the
       nearest star to the Sun is 4.3 LY away.  Also any signal
       attenuation due to the Earth's atmosphere and ionosphere have
       been ignored; AM radio, for example, from Earth, is trapped
       within the ionosphere.

       The receive antenna area, Aer, is

         Aer = <eta>r * pi * dr^2 / 4 = 36.5E3 m^2.

       (Scientific notation is being used here; 1E1 = 10, 1E2 = 100,
       1E3 = 1000, so 36.5E3 is 36.5 times 1000.)  Hence the detection
       range (light years) becomes

         R = 3.07E-04 * sqrt[ EIRP / (Br * Tsys) ].

       Table 1 Detection ranges of various EM emissions from Earth and
               the Pioneer spacecraft assuming a 305 meter diameter
               circular aperture receive antenna, similar to the Arecibo
               radio telescope. Assuming snr = 25, twp = Br * Tr = 1,
               <eta>r = 0.5, and dr = 305 meters.
Source       | Frequency    | Bandwidth | Tsys   | EIRP   | Detection |
             | Range        |    (Br)   |(Kelvin)|        | Range (R) |
AM Radio     | 530-1605 kHz |  10   kHz | 68E6   | 100 KW |  0.007 AU |
FM Radio     |  88-108  MHz | 150   kHz |  430   |   5 MW |    5.4 AU |
UHF TV       | 470-806  MHz |   6   MHz |  50  ? |   5 MW |    2.5 AU |
Picture      |              |           |        |        |           |
UHF TV       | 470-806  MHz |   0.1  Hz |  50  ? |   5 MW |    0.3 LY |
Carrier      |              |           |        |        |           |
WSR-88D      |   2.8    GHz |  0.63 MHz |  40    |  32 GW |   0.01 LY |
Weather Radar|              |           |        |        |           |
Arecibo      |   2.380  GHz |  0.1   Hz |  40    |  22 TW |    720 LY |
S-Band (CW)  |              |           |        |        |           |
Arecibo      |   2.380  GHz |  0.1   Hz |  40    |   1 TW |    150 LY |
S-Band (CW)  |              |           |        |        |           |
Arecibo      |   2.380  GHz |  0.1   Hz |  40    |   1 GW |      5 LY |
S-Band (CW)  |              |           |        |        |           |
Pioneer 10   |   2.295  GHz |  1.0   Hz |  40    | 1.6 kW |    120 AU |
Carrier      |              |           |        |        |           |

       It should be apparent then from these results that the detection
       of AM radio, FM radio, or TV pictures much beyond the orbit of
       Pluto will be extremely difficult even for an Arecibo-like 305
       meter diameter radio telescope!  Even a 3000 meter diameter radio
       telescope could not detect the "I Love Lucy" TV show (re-runs) at
       a distance of 0.01 Light-Years!

       It is only the narrowband high intensity emissions from Earth
       (narrowband radar generally) that will be detectable at
       significant ranges (greater than 1 LY).  Perhaps they'll show up
       very much like the narrowband, short duration, and non-repeating,
       signals observed by our SETI telescopes.  Perhaps we should
       document all these "non-repeating" detections very carefully to
       see if any long term spatial detection patterns show up.

       Another question to consider is what an Amateur SETI radio
       telescope might achieve in terms of detection ranges using
       narrowband FFT processing.  Detection ranges (LY) are given in
       Table 2 assuming a 12 ft (3.7 m) dish antenna operating at 1.42
       GHz, for various FFT binwidths (Br), Tsys, snr, time bandwidth
       products (twp = Br*t), and EIRP values.  It appears from the
       table that effective amateur SETI explorations can be conducted
       out beyond approximately 30 light years provided the processing
       bandwidth is near the minimum (approximately 0.1 Hz), the system
       temperature is minimal (20 to 50 Degrees Kelvin), and the EIRP of
       the source (transmitter) is greater than approximately 25

       Table 2     Detection ranges (LY) for a 12 foot diameter amateur
                   radio telescope SETI system, operating at 1.420 GHz.
                                 |             EIRP              |
                                 | 100TW |  25TW  |  1TW | 100GW |
   Br  | Br*t  |   Tsys   | snr  |        Detection Range        |
  (Hz) |       | (kelvin) |      |             (LY)              |
  0.1  |   2   |    50    |  25  |   28  |    17  |  3.4 |   1.1 |
  0.1  |   1   |    50    |  25  |   20  |    12  |  2.4 |  0.76 |
  0.5  |   2   |    50    |  25  |  12.7 |    6.4 |  1.3 |   0.4 |
  0.5  |   1   |    50    |  25  |    9  |    4.5 |  0.9 |   0.3 |
  0.1  |  20   |    50    |  25  |   90  |    54  |  11  |   3.4 |
  1.0  | 200   |    50    |  25  |   90  |    54  |  11  |   3.4 |

              Radio Astronomy, John D. Kraus, 2nd edition,
              Cygnus-Quasar Books, 1986, P.O. Box 85, Powell, Ohio,

              Radio Astronomy, J. L. Steinberg, J. Lequeux, McGraw-Hill
              Electronic Science Series, McGraw-Hill Book Company, Inc,

              Project Cyclops, ISBN 0-9650707-0-0, Reprinted 1996, by
              the SETI League and SETI Institute.

              Extraterrestrial Civilizations, Problems of Interstellar
              Communication, S. A. Kaplan, editor, 1971, NASA TT F-631
              (TT 70-50081), page 88.

       (this section taken from sci.asto FAQ, see 5.1 for the copyright
        statment of sci.astro FAQ)

       Also see section 1.6


       By Carl Sagan

       Cosmic Search Magazine Vol. 1 No. 2 May, 1978

       Through all of our history we have pondered the stars and mused
       whether mankind is unique or if, somewhere else out there in the
       dark of night sky, there are other beings who contemplate and
       wonder as we do - fellow thinkers in the cosmos. Such beings
       might view themselves and the universe differently. Somewhere
       else there might exist exotic biologies, technologies and
       societies. What a splendid perspective contact with a profoundly
       different civilization might provide! In a cosmic setting vast
       and old beyond ordinary human understanding we are a little
       lonely, and we ponder the ultimate significance, if any, of
       our tiny but exquisite blue planet, the Earth. The Search for
       Extra-Terrestrial Intelligence (SETI) is the search for a
       generally acceptable cosmic context for the human species. In the
       deepest sense the search for extraterrestrial intelligence is a
       search for ourselves.

                                 ~ ~ ~ ~ ~

       There are some who look on our global problems here on Earth - at
       our vast national antagonisms, our nuclear arsenals, our growing
       populations, the disparity between the poor and the affluent,
       shortages of food and resources, and our inadvertent alterations
       of the natural environment of our planet - and conclude that we
       live in a system which has suddenly become unstable, a system
       which is destined soon to collapse. There are others who believe
       that our problems are soluble, that humanity is still in its
       childhood, that one day soon we will grow up. The existence of a
       single message from space will show that it is possible to live
       through technological adolescence: the civilization transmitting
       the message, after all, has survived. Such knowledge, it seems to
       me, might be worth a great price.

                                 ~ ~ ~ ~ ~

       There will surely be differences among civilizations which cannot
       be glimpsed until information is available about the evolution of
       many civilizations. Because of our isolation from the rest of the
       cosmos, we have information on the evolution of only one
       civilization - our own. And the most important aspect of that
       information, the future, remains closed to us. Perhaps it is not
       likely, but it is certainly possible that the future of human
       civilization depends on the receipt and decoding of interstellar
       messages...It is difficult to think of another enterprise within
       our capability and at relatively modest cost which holds as much
       promise for the future of humanity.

1.2.5  Setup of the SETI@home project

       This was taken from a.s.s, and written by Eric J. Korpela,
       responding to a post by <>

       The Ultra 450 (4 cpu) is the science database server which stores
       results, does analysis, and also runs a splitter process.

       One Ultra 10 is the user database server which stores user

       One Ultra 10 workstation is the server machine which handles
       connections and directs them to the appropriate database This
       machine also has storage for the workunits themselves.

       One Ultra 10 is a full time splitter.

       Two Ultra 10s (one fast and one slow) are development
       workstations and an after hours splitters.

       One slow Ultra 10 is the web server and Dan's workstation. (Dan

       One Sparcstation 10 used to be a splitter (that's the old really
       slow one) and is used as a development workstation.

1.2.6  What is a Gaussian?

       A gaussian is a mathematical function, mostly commonly describing
       the sort of distribution of values you get around the nominal
       value of some property or measurement as a result of measurement
       (and production errors).  I would expect the maximum speeds of
       CPU chips to show this sort of pattern.

       It is often described as a bell curve, as it starts off rising
       slowly, then accelerates before starting to level off and come
       down in a mirror image of its rise, something like the cross
       section of a church bell.

1.2.7  Analysis of the end data from the SETI@home project

       First thing, they'll be run through some RFI (Radio Frequency
       Interference for the newbies out there) rejection routines.
       There are a few different algorithms used. If a signal at the
       same frequency, but from a different place on the sky comes in
       within a few minutes, it's likely to be RFI.
       There are certain frequencies where continuous RFI is received,
       that will also be rejected. If a signal comes in at a chirp rate
       of zero, it's also likely to be RFI (extraterrestial signals
       should show a chirp signature due to the rotation of the earth
       and/or the rotaion of the ET's planet.)  RFI rejection will
       probably eliminate the vast majority of the candidates (>99.99%).

       From there, the probablility that the candidate signals are just
       a random peak in the noise in the reciever, will be calculated.
       Then there'll be created a priority list of candidates based upon
       this probability, the signal strength, frequency width, goodness
       of gaussian fit, etc and pointed observations of the best
       candidates will be proposed.

       Somewhere in this chain, there'll also be looked for repeaters.
       Signals that show up at the same place in the sky at about the
       same frequency, but widely separated in time.  Repeaters will
       likely get bumped to the top of the priority list.

       Another thing that will be looked for is signals with decent
       gaussian fits that show up at different frequencies, but at the
       same time.  That might boost a candidates' priority as well.

1.2.8  What are pulses and triplets?

       In the contexts of SETI@home, they are spikes that are repeated
       many times. Triplet means that there are three evenly spaced
       spikes. The triplet detection takes very little time to do, but
       it can only detect strong signals.

       The pulse finding algorithm can find very weak pulses, the more
       pulses the better the algorithm can find them. The pulse seeking,
       however, takes alot more time to do.

1.3    The history and customs of alt.sci.seti and sci.astro

1.3.1  Charter for alt.sci.seti

       The original documents can be found here:

       The first post:[ST_rn=ap]/getdoc.xp?AN=484562021&CONTEXT=

       The control message, that created the group:[ST_rn=ap]/getdoc.xp?AN=484419771&CONTEXT=

       This was posted as the first post ever in alt.sci.seti on June
       1st by Chris:

       Welcome to "alt.sci.seti" This group will probably be a little
       barren at first until it begins to propagate more thoroughly Why
       not post a message and get things rolling?

       Hopefully someone will one day create a FAQ for this newsgroup,
       but until then here's the charter...


       Discussion about the SETI (Search for Extra Terrestrial
       Intelligence) project and the search for extra terrestrial life
       in general.

       Also, discussion of the "SETI@home" project which allows
       individuals to utilize their computer's idle time to assist SETI
       in processing its overwhelming amount of recorded data.

       Should discussion about the SETI@home project and the SETI
       project in general begin to crowd eachother, a second newsgroup
       devoted solely to SETI@home will be created with the name
       "" leaving "alt.sci.seti" for discussion of
       the SETI project.

       Binaries are not permitted and should instead be posted to the
       appropriate binary newsgroup or FTP site where they may be


       The SETI project has been going on for some years now and has
       amassed a great deal of interest. A quick search on DejaNews will
       show that there are thousands of posts regarding SETI, yet there
       is no currently available newsgroup to keep these discussions
       from getting lost in numerous other non-specific forums.
       "alt.sci.seti" will address this lacking.

       It will also provide a place for the enormous and growing number
       of people who have begun to participate in the SETI@home project
       to discuss problems and solutions in assisting SETI to process
       all of its raw data. While the SETI@home project is expected to
       end around 2001 or so, it is likely that SETI will seek to call
       upon the public again in a similar way. This newsgroup will
       therefore continue to be timely and useful.

       This newsgroup was proposed, discussed, and approved in
       "alt.config" at the end of May 99.

       Created 01 Jun 99

1.3.2  Charter for sci.astro.seti

       RATIONALE: sci.astro.seti

       The Search for Extraterrestrial Intelligence (SETI) is the
       scientific discipline of searching for electromagnetic evidence
       of extraterrestrial civilizations.  SETI has received a lot of
       attention recently due to the SETI@home project.  The SETI@home
       project has shown that at least several hundred thousand
       individuals are willing to dedicate computer resources to the
       search for alien radio signals. This has brought an increase in
       the amount of discussion of SETI and the possibilities of
       extra-terrestrial intelligence (ETI).  Which has increased the
       number of posts about SETI in related newsgroups (sci.astro,
       etc.) by a large amount.

       The SETI@home project is a distributed computing project which
       harnesses the computing power of hundreds of thousands of
       Internet connected computers to search for radio evidence of
       extraterrestrial civilizations.  It is the newest and most public
       SETI project to date. Currently it has attracted almost a million
       people willing to donate computer time to this search.  However,
       SETI@home is not the only SETI project, nor will it be the last
       new one.  Several SETI projects are on the drawing board (1HT,
       etc.) and many of them will require as much or more computing
       power as the SETI@home project uses currently.  It would be
       surprising if none of these new SETI programs use the distributed
       computing model that has allowed SETI@home to harness computing
       power equivalent to multi-million dollar super-computers for very
       low costs.

       This newsgroup will serve as a forum for discussion of SETI in
       general, and any SETI projects in specific.  This includes
       discussion of SETI@home, both it's scientific aspects, as well as
       the use, configuration, and troubleshooting of the SETI@home
       client software and any similar software by future SETI projects.
       Additionally, it will serve as a place to discuss the technical
       specifics of all current and future SETI projects, and as a place
       for teachers who are developing curricula around SETI projects
       (such as SETI@home).

       CHARTER: sci.astro.seti

       This group will be unmoderated and distributed worldwide.  This
       newsgroup is intended for the discussion of the Search for
       Extra-Terrestrial Intelligence. Appropriate topics for discussion
       include the following:
       1) Discussion of SETI projects (such as SERENDIP, Phoenix,
          SETI@home, BETA, ARGUS, etc.)
       2) Installation and configuration of the SETI@home client
          or other SETI projects using distributed computing.
       3) Trouble shooting the use of the SETI client programs.
       4) The possibilities of Alien life (Drake equation, planetary
          abundance and its relavance to SETI, etc.)
       5) Discussion of statistical results for SETI projects.
       6) The potential content of alien messages and how to decode
          them, as well as any messages we (humans) have / will /
          could send into space that are intended for ETI's (such as
          the Voyager record, the Arecibo message to M13, the Encounter
          2001 project, etc.)
       7) Potential alien technology in the context of detection /
          communication by / with humans (using visible light lasers
          instead of radio, for example).
       8) Discussion of school curricula built around a SETI

       Inappropriate posts include:
       1) Commercial advertisements of any kind, including those for
          items related to SETI or any SETI project.
       2) Binaries, with the exception of cryptographic signatures.
       3) Discussions concerning UFOs, "alien abductions", etc,
          which should take place in other groups.

1.3.3  Naming convention

       When talking about your computer(s) on the newsgroups, the
       following information is the minimum for other people to be able
       to determine if the machine is working optimally.

       CPU-TYPE, for example Pentium MMX, AMD Athlon, Pentium III....
       CPU-SPEED, 133Mhz, 600Mhz....
       Memory size
       Memory type
       FSB-speed (Front side bus speed)

       Also useful to include:
       Motherboard chipset
       Operating System

1.3.4  .sig convention

       When reading the SETI newsgroups, you will find, that many use a
       * or # in their signatures. This strange way of bragging was
       first seen when the first people in alt.sci.seti started getting
       close and passing 100 Workunits done. They wanted to give
       themselves something for their effort, so they started giving
       themselves medals, putting them in their sig. Initially there was
       only one character used, the star (*) which you 'earned' for
       every 100 WU's. As time passed by, people started using more and
       more complex notations, which evolved into the complex system we
       have today.

       The newest .sig convention is as follows:

       The following notation is a way of expressing your personal or a
       group's contribution to the S@H program.


       These formats imply a certain range.
       2.3* would for instance mean the interval of 230-239, whereas
       2* would mean 200-299. The same goes for the symbolic notation.
       For instance ** would mean the interval of 200-299. More decimals
       added will imply greater accuracy for FORMAT 1 and more
       characters added would do the same for FORMAT 2.

       FORMAT 1:


       Where "d" is a digit and "s" one or a combination of the
       following symbols:

       !#=10000   (ten thousand)
       *#=100000  (hundred thousand)
       ##=1000000 (thousand thousand) etc...


       This table can be used for workunits and cpu-time alike.
       "@" only as a separator.


       9@9.8!             (9wu/98hr)
       1.0!@2.5*          (10wu/250hr)
       2.1#@3.4!#         (2100wu/34000hr)
       3.0*#@3.6##        (300000wu/3600000hr)

       FORMAT 2 - a more symbolic notation:

       Where the notation is composed of only symbols:



       This table can be used for workunits and cpu-time alike.
       "@" only as a separator.


       ****+@###          (450wu/3000hr).
       All symbols are counted for their value and finally added up.
       Here 100+100+100+100+50=450wu in 1000+1000+1000=3000hr.

       It is preferred to sort the symbols. The greater first, then the

       FORMAT 3 - only work units:

       Format 1 or 2 where the cpu-time portion has been omitted.


       2.1# (2100wu), ****+ (450wu).

       FORMAT 4 - the most simple and understandable:


       DERIVED FORMATS - not preferred but no less understandable:

       Mixed schemes may occur. E.g.: 4*+@3# (450wu/3000hr).

       Today, there's even a program that will automatically make and
       update the signature for you! The program is available for
       Windows at
       (requires VB6 runtime libraries)

       In addition many people have begun marking their posts with a
       short statement, indicating their opposition towards Olli (1.3.6)
       It usually goes something like this:

       +++++++     DO NOT USE SETI@HOME PATCHES     +++++++

       It's inserted just before or in the .sig

1.3.5  Labeling posts

       As there are many discussions about things not so relevant to
       SETI in these newsgroups (a.s.s. and s.a.s.), there have been
       developed many schemes, on how to label the posts.
       I suggest labeling posts in this newsgroup as follows:

       [sci]   About science in general with no content about SETI@home
       [meta]  Discussions about discussing things
       [comp]  Discussions about computing with no content about S@H
       [ot]    Off-Topic: has nothing to do with SETI in any way.
       [patch] Discussions about patching the SETI@home client program.
       [brag]  General bragging about your computer's speed, etc.
       [join]  Invitations to join groups.
       [FAQ]   Postings of Frequently Asked Questions or comments.
       (no label) Discussions about the SETI@home project, client, etc.

       Insert the [*] after any "Re:". Some newsreaders use the "Re:"
       to display which posts are replies.  Please leave a space after
       the ":" in "Re: ".  Not doing so confuses some newsreaders.

       Don't make up new tags.  Make the tag general and the text after
       the tag specific.  If you think that a new tag is needed, start
       a discussion about it under [meta] (NOT under the proposed tag!).

       If someone doesn't follow the rules. don't criticize.  This is
       100% optional.  Posters are free to do as they choose.  Limit
       your efforts to gentle persuasion only.

       The single most effective thing that you can do to promote this
       idea is to change the subject line and write a new one before the
       old one, so that the subject will be like this: Subject: <new
       subject> Was:<Old subject>.

       OFF topic:

       1. BINARIES - a big NO.
       2. ANY commercial advertising.
       3. Number of WU's done. Use your .sig file to brag.
       4. Personal Chit-chat use [ot].
       5. Posts about how old you are, what you do, etc. use [ot].
       6. How fast your CPU is as compared to others. [brag]

1.3.6  Patching or cracking SETI@home


       When you hear a reference to Olli in the group, this is a
       reference to a German who thought, that he could just do as he
       wanted with the S@H program. What he did, essentially, was to
       decompile the code of the program, and release a new version of
       the program, unauthorized. This led to a big discussion in the
       alt.sci.seti NG, where he was eventually boo'ed out, because of
       his actions.

       Microsoft cracking the code:

       Microsoft wrote their own version of SETI, highly optimized for
       certain Windows hardware. They wanted to turn in the fastest WU
       times, to prove how fast Windows is. The SETI people discovered
       MS's cheating, and told them they must run the original SETI
       software, and threatened to dissolve the MS team, and said they
       would refuse results from any WU processed on a non-official SETI
       client. SETI had obvious concerns, that their algorithms might be
       programmed incorrectly.

       SETI@home's (Eric J. Korpela) response to a post concerning the
       programming variables of the patch:


       From: (Eric J. Korpela)
       Newsgroups: alt.sci.seti
       Subject: Re: seti patch bashing or the truth is...
       Date: 28 Oct 1999 16:06:33 GMT
       Organization: Cal Berkeley-- Space Sciences Lab
       Lines: 147
       Message-ID: <7v9sa9$ror$>

       In article <7v7b3b$70l$>,
       ******* ******* <*********> wrote:
       >In article <7v4phg$1vv$>,
       > (Eric J. Korpela) wrote:
       >> In other words, if I don't get the same results using a hammer
       >> on a screw that I do using a screwdriver then something is
       >> wrong with the screwdriver?
       >> Olli has provided a means by which anyone with a compiler can
       >> replace the FFT routine with one that produces random
       >> numbers.  Your conclusion would be that if the random number
       >> generator gets different results than the FFT does, something
       >> is wrong with the FFT.
       >Excuse me, but I have to ask. Are you really a programmer?

       Well, that depends upon how you define "programmer."  I'm
       actually a scientist.  My profession requires me to be a
       capable optical engineer, electrical engineer, mechanical
       engineer, and programmer.  Above all it requires me to be a
       proficient systems engineer.  And one of the things Olli's patch
       is missing is any consideration of the system aspects.

       Let me tell you some of the system aspects.  The bottlenecks in
       SETI@home are currently (in order of size):

       1.  The speed of the user database machine.  This limits the
           number of connections we are able to handle per second.  Sun
           has decided to give use another two Enterprise machine with
           two CPUs each, so this bottleneck will be going away soon.
           It will probably be another month before these machines
           arrive.  The effect of a faster client on this bottleneck
           would be a higher rate of rejected connections and a lower
           system efficiency.
           -1 for Olli.

       2.  The rate at which work units can be split.  The arrival of
           the two Enterprize machines will allow two more splitters to
           be used, to this bottleneck will go away, too.  The effect
           of a faster client on this is nothing.
           +0 for Olli.

       3.  The fraction of time the S@H recorder is operating at
           Arecibo. We have no control over this parameter.  When very
           RFI sensitive
           experiments are carried out at Arecibo, the SETI@home data
           recorder is shut off to prevent interference.  For the first
           10 months of the year(1999 ed.), this fraction was about 1/2.
           The effect of a faster client on this is nothing.
           +0 for Olli.

       4.  The speed of the data recorder at Arecibo.  Again, there's
           nothing to be done here but add another recorder working at
           different frequecies. That may be done at some point.  The
           effect of a faster client on this is nothing.
           +0 for Olli.

       5.  The speed of the SETI@home client.  Note that this appears
           BELOW the previous four.  Because of this, improving it
           doesn't improve systems efficiency.  Let's assume #1 and #2
           are solved and that we release a client that does the work
           in 1/4 the time.  What is the response of the system to this
           optimization?  Because data isn't coming in any faster, any
           speed increase in the client just increases the number of
           times a work unit is processes.  Increase the speed of the
           client by a factor of 4 and you've increased the processing
           redundancy by a factor of 4. So there's no net processing
           efficiency increase.  You've still got to store all the
           incoming results, so you're actually reducing efficiency
           slightly.  So this is actually a negative for Olli.
           -1 for Olli

       The obvious conclusion is that Olli's patch, while increasing
       the efficiency of a specific instance of the SETI@home client
       decreases the system efficiency. But Olli doesn't care about

       There is a way around number 5, that is to add more
       processing capability to the client.  This is what we were
       planning to do in the next release before we were so rudely

       >I have seen
       >several posts in these threads that appear to be from you
       >that suggest you don't understand some things that I have
       >always considered pretty basic.

       I understand a bit more than you appear to.

       >If you are a scientist in general and a computer scientist
       >in particular, then I would think your primary concern would
       >be in getting the best tools to resolve the research
       >question in hand.

       Sorry, you don't seem to understand science.  Faster doesn't mean
       better. And trustworthy is far better than faster.  (Did you
       notice Olli's message stating that he would add malicious code to
       an employer's system in case he was fired "for the wrong reason."
       I would guess he considers adding malicious code to an employer's
       system "the wrong reason.")

       In addition, a scientist doesn't add unnecessary variables to an
       experiment. A different FFT algorithm for every platform is an
       unnecessary variable.

       >If you are not competent to assess his optimizations, that is
       >merely an unfortunate technical gap that you can choose to

       Pardon me if I take offense to your insults.  I never said we
       weren't competent to assess his optimizations.  We don't have the
       time to deal with the patches every yahoo with a debugger and a
       compiler throws our way.

       >I'm not suggesting you should give up control of your project.

       Look at the SETI@home web page... I never had control of the

       >But neither is it the case that your enthusiasm is holy and
       >other people's enthusiasm is cursed.

       When his enthusiasm leads him to give everyone with a compiler
       control of the science code, I'd call that cursed.

       >1) Optimize your inner loops better.

       We're working on it.

       >2) Learn about code signing.

       I think you're misunderstanding code signing.  Code signing is
       used as proof to the user of who created the code, not as a
       means of preventing the user from tampering with the code.
       Even Olli will tell you that even if the code checks it's
       signature before running, that check ends in one or more
       conditional jumps that are easily removed.  The other option is
       encrypting the entire executable, but even then you need to
       provide in the executable a decryption routine and a key.
       If you give the hacker those, you've given him the equivalent
       of a decrypted executable.  Actually you don't even need those
       as the code decrypts itself to memory where it is easily

       >3) Consider modularizing your client.

       No way.

       >The last suggestion is most complicated, but if implemented
       >properly, it would actually allow you

       and everyone else on the planet

       > to reprogram the clients as your needs

       or their desires

       >required without even distributing new versions.


       Eric Korpela                    |  An object at rest can never be        |  stopped.


       And another post made by Matt Lebofsky of the S@H team,
       concerning the ethics of patching:


       From: (Matt Lebofsky)
       Newsgroups: alt.sci.seti,sci.astro.seti
       Subject: Re: Found Olli's Patch !
       Date: 13 Dec 1999 17:31:52 GMT
       Organization: Space Sciences Laboratory
       Lines: 61
       Message-ID: <833ai8$pd1$>

       Despite all the reasons below being completely valid, I'll give
       you another one:

       SETI@home doesn't allow unauthorized access to our data server.
       Patched clients which look like real clients that contact our
       server could, in theory, do any number of things that cause
       harm. In short, it's a form of hacking.

       Of course people believe the patch is safe and accurate. We here
       at SETI@home don't know that, nor has the patch creator been
       willing to prove it. The author of this patch even goes as far
       as to completely *refuse* to identify his patch so our server
       can recognize it as a patched client. To me, this is an obvious

       In short, we can't tell if results are from patched clients or
       not. The patch could easily be modified to fix this. It hasn't
       been. Case closed.

       Too bad I didn't know about Olli before I went touring in
       Germany for five weeks this past summer. Hopefully I'll be back
       again in fall of '00. If anybody knows where he lives/works/hides
       let me know. I'd like to discuss the patch in person.

       This is my first AND last message on the matter.

       - Matt - SETI@home

       In article <8327ak$ln4$>,
       Daviddth  <> wrote:
       >In article <>,
       > (Jan Knutar) wrote:
       >>>Found Olli's Patch !
       >Please tell us why not. In your answer, please do not include:
       >Morality - Your morals may not be others
       >Scientific results - The patch has proven itself accurate here
       >in multiple tests
       >Scientific "purity" - if the patch is accurate, but quicker,
       > then what is the problem in using it.
       >Dislike of Olli - There are plenty of people that do not like
       > others, but respect their work. Learn to live with this anger.
       >I await your reply.


       Please note that these Usenet posts that have been quoted here
       aren't meant to represent the absolute truth, they are meant to
       give you SETI@home's opinion on patching, and to give you some
       interesting reading.

       There's an excellent page, dedicated to this very subject here:

1.3.7  What is a 'vcard' and why do people tell me not to use them?

       A vcard is only readable by a newsreader capable of rendering
       html. For this reason and because vcards are 'attached' to the
       Usenet posting, they are not recommended. They are also very
       annoying in that they very rarely change. This is analogous to
       giving everyone you talk to your business card each and every
       time you talk with them... after a while, we have enough of your
       cards, and we really don't want any more. A signature is the
       preferred method to communicate pertinent personal information.
       Please see the section on 'signatures' or '.sig' for more

1.3.8  What is PST and PDT?

       They're timezones ;)

       PST - Pacific Standard Time (GMT - 8)
       PDT - Pacific Daylight Time (GMT - 7)

       (GMT = Greenwich Mean Time)

1.4    What will happen if an extraterrestrial signal is detected?

       A procedure has been agreed upon by SETI researchers around the
       world. First, other SETI researchers will independently verify
       the signal. If the signal is real and can't be explained by
       man-made sources (satellites, reflections, etc.) then press
       agencies and governments will be notified in a systematic way.

1.5    How is data collected from the telescope and transmitted to other
       machines for analysis?

       Data is recorded on high density tapes at the Arecibo telescope
       in Puerto Rico, about one 35 Gbyte tape per day, then mailed to
       Berkeley, then divided into 0.25 Mbyte chunks which get sent from
       the SETI@home server over the internet to people around the world
       to analyze. Arecibo does not have a high bandwidth internet
       connection, so data must go by snail mail to Berkeley at first.

1.6    Are earth signals strong enough to be detected?

       What sort of spectrum is currently being emitted by earth? Is
       that signal visible say 10 or 50 light years away? If SETI were
       on a planet say 10-50 light years from here and running this
       project there, would it be able to detect earth's signal
       (assuming it was looking in our direction)?

       Earth is polluting space with radio and television signals that
       might be detected by nearby advanced civilizations, but it would
       be difficult for such a civilization to discover these signals if
       they only have Earth's current level of technology (eg: if they
       have an Arecibo like telescope and SETI@home like search).

       Early TV shows like I Love Lucy and Ed Sullivan left the earth
       about 40 years ago, so have gone out 40 light years, reaching
       several thousand nearby stars. But these signals are relatively
       weak and SETI@home is not likely to detect the equivalent of
       Earth type TV transmitters, even on the nearest stars.

       Earth's strongest transmitters might be somewhat easier to
       detect, such as those emitted by military radars, or some radio
       telescopes. The Arecibo telescope transmits very powerful signals
       when it is used as a radar system to study planets, asteroids and
       the ionosphere. These radar signals are powerful enough to be
       detected 10,000 light years away by searches like SETI@home,
       except for three big caveats:

       a) The Arecibo transmissions are in a very tight beam (they are
          not omnidirectional, like TV and military radar), so they only
          cover a very small part of the sky at once (about a millionth
          of the total sky). It's is unlikely another civilization will
          be within one of these narrow beams.

       b) The Arecibo transmitter's oldest signals left Earth about 30
          years ago, so have only travelled 30 light years.

       c) SETI@home is not searching the band of frequencies that the
          Arecibo transmitters utilize (although the older SERENDIP III
          program did survey one of those bands).

       Also see section 1.2.3

1.7    What if my computer finds a signal -- how will I know?

       You won't know, because your computer can't find a signal all by
       itself. All it can find is bits of pattern that are worth further
       investigation and correlation with other bits of pattern in other
       work units. These will be flagged for the SETI@home staff to look
       into, and when they've verified it by various methods with
       scientific rigor, then they'll make the announcement. Don't worry
       -- they'll give you co-credit.

1.8    How can I hear the signal?

       The long answer: the data isn't sound, it's radio waves. You can
       make up an arbitrary set of rules to "map" radio waves into
       sound, but since you picked the rules, you really decide what
       you're hearing, not the signal. As an analogy, imagine if you
       wanted to make a picture of the melody of a song was. You could
       decide (ala "Close Encounters") that a middle C turned into a
       teal light, and the G above middle C turned into a red light.
       Then any given melody becomes a set of colors. But when you're
       done, the flashing lights you see tell you more about the
       particular rules of mapping you made up, than they did about the
       melody you started with.

       The short answer: And even if you did, it'd just sound like white
       noise. So turn on some speakers without any signal hooked up to
       them, or tune your TV to a channel you don't get, and listen do
       that. It's about the same thing.

       The SETI@home team has decoded one, and it's located her:

       Nothing but white noise.

       Jan Knutar has made a program that maps the radio waves into
       sound atleast one way, the result sounds, not surprisingly, like
       noise. The program, which is available for both Linux and Windows
       PC's, is downloadable at

1.9    Is there something in it for me?

       No. Unless you count the chance to be the first one to make
       contact with "The little green men"

1.10   Why doesn't SETI@home release the sources for the clients?

       The sourcecode is not released because of both security and
       scientifical reasons. If the code was available freely, anyone
       could replace the core analyzing algorithm with some superfast
       random number generator, for example. SETI@home is a scientifical
       project, speed is not everything.

       In the newsgroups, it has been hinted that the source will be
       released when the project is over.

       There are actually small pieces of the sourcecode available. Some
       of the early clients were GPL'd, and you can find the sourcecode
       for them on the Internet.

       In a post to alt.sci.seti by Eric Heien, additional details of
       the code used was given. Parts of the post below:

       In the old versions, we used the four1 procedure for FFTs from
       Numerical Recipes in C.  You can see the exact code and
       scientific and mathematical derivations for it in Numerical
       Recipes in C.  It's available at, or you can just jump
       directly to
       for the specific section.

       The new FFT used in the beta versions (and soon version 3.0) is
       the Ooura FFT library.  You can get the code and benchmarks at

       The new pulse finding code is called the Fast Folding Algorithm
       (FFA). I'm sure there are several sources and papers for it on
       the Internet, but the first I saw was  This
       particular analysis routine was written by us, but was based on
       code that is publicly available (for example, from the above

       The triplet code is based on ideas developed by some NASA
       scientists (I don't know their names offhand).  The code was
       actually entirely written here rather than based on other code,
       but I'm sure there are papers and sample code available somewhere
       out there for it.

       See also SETI@home's official FAQ at

2      Problems and questions concerning SETI@home

2.1    Speed improvements

2.1.1  What's the fastest computer to use for this project?

       The computer you have. If it can run SETI@home, running it will
       make more contribution than not running it. Even if you're only
       doing half as many work units per month as the guy sitting next
       to you, you're still doing more than you would if you weren't
       doing them at all. If you want to see, what the fastest computer
       possible is, check the following sections.

2.1.2  Can I make it run any faster?

       1. Make sure you've got it set up to run continuously (a machine
          with at least a 200 MHz clock is desirable; if an Intel
          Platform then at least a BX or JX chip set is even better,
          otherwise the performance of the system might be untolerable)

       2. Each time SETI@home launches, it optimizes itself for the
          current monitor color depth (256 colors, Thousands, Millions).
          If you change the color depth while SETI@home is running,
          it may slow things to a crawl.

       3. It should run reasonably at any screen depth, but it will run
          somewhat faster at lower screen depths (256 colors) than
          higher ones. Screen resolution (800X600, 1024X732, etc.)
          should have negligible effect on speed.

       4. Make sure the graphical display window is never showing (run
          the window collapsed on the task bar)

       5. If running Windows 95/98/NT, make sure your screen saver is
          set up for "Blank Screen". For some reason when screen saver
          is set to "SETI@home" with "continuous run" enabled the client
          seems to waste time fighting with itself. It can turn out a
          work unit in half the time by doing this.

       6. If running on WindowsNT 4 then try running the client at a
          higherpriority. To do this you must do the following:
          4a. do a 3 finger salute (ctrl-alt-del) to bring up the
              "Windows NT Security" panel
          4b. click the "task manager" tab
          4c. locate the task called SETI@home
          4d. right click on it
          4e. clink task priority (low is the default)
          4f. select either "medium" or "high" (but not "real time" or
              you might need to reboot in order to regain control of
              your machine)

          On windows 9X, you can use the shareware program taskinfo.
          Start Taskinfo, right click SETI@home, change priority,
          realtime. Taskinfo can be found at

          Be warned, changing the priority to realtime is for the
        purists only. It will give nearly all CPU time to the S@H
        client, making your system unresponsive.

       7. Use the text-client. Even though it's not as much fun as the
          graphical, it does run faster. It will run on any win98/NT
          system (NT calls have been ported to win98. The text client
          will also run on Windows 95 if you upgrade Winsock to
          version 2. You can find the upgrade at Microsoft's website

2.1.3  REMOVED March 2000, was:
       Can I run the SETI@home text-client on Win95?

       Now appears in section 2.21.

2.1.4  Will SETI@home run faster with more RAM (e.g., 256 MB instead of
       128 MB)?

       SETI@home uses about 16 MB of RAM while it's running. Beyond a
       certain point (typically 64MB, more if you run memory-itensive
       applications) more RAM won't make it run faster.

2.2    REMOVED April 2000, was:
       I'm using a proxy server, and I can't connect - what do I do?

       Was removed because the SETI@Home client's hugely improved proxy
       support. Consult 2.20 for help on the CL client.

2.3    I had a work unit that got returned after only 5 minutes. What's

       The SETI@home program found enough noise that it determined the
       packet was messed up with it. It's like if you're trying to hear
       an egg being dropped to the ground on the other end of a football
       field, and someone blares a megaphone in your ear. No point in
       continuing to listen for the egg. You wont get credit if it took
       under 10 minutes to complete the workunit. This is to eliminate
       results from the buggy mac clients that finished all workunits in

       There are a few examples of excessive noise in workunits at the
       SETI@home website:

2.4    I heard I was getting the same work unit as everyone else. Is the
       program wasting my time?

       Nope, because the only time you're giving it is time your
       computer would have wasted anyway. Yes, early in the program
       there were times when the same work units went out over and over,
       due to overloading of the SETI@home servers that were supposed to
       be making new ones to send out. (They didn't expect half a
       million people to sign up, and they don't have enough staff or
       computing power to keep up with it.)
       And since then, the same work units are still sent out to several
       people, for various reasons (for instance, more than half the
       people who signed up have never returned their work units, and
       probably dropped out) But new work units are being sent out too,
       so just leave your SETI@home program working and it'll take care
       of the details.

       If workunits are sent out multiple times, they can be
       doublechecked by SETI@home.

2.5    My computer wanted to upload to the SETI@home server but said it
       couldn't connect or reported error 10065. Are they still there?

       Yes But they're sometimes swamped with traffic. Just try again
       later. Error 10065 is a winsock error - means the same.

       The page is
       auto-generated and tells you whether SETI@home's data server is
       running or not.

       Sometimes the error might be between your ISP and Berkeley,
       sometimes at your ISP. Most operating systems have tools to help
       you determine where the error is. If you want to try to find out
       what's wrong when you can't connect, try using the 'traceroute'
       command (in Windows: tracert). You bring up a command prompt and
       type in the command followed by the site you wish to connect to,
       in this case (for the S@H server).

       If you get "Cannot resolve" or similar error, then your computer
       was unable to translate the address into an IP number. The cause
       of that could be that your ISP's DNS server is down or not
       working properly.

2.6    What if someone fakes a result to make it seem like they found a

       The SETI@home staff will be reviewing the actual data that
       produced the result, and if they don't find the same results,
       they will discard the fake. Besides, while it's not impossible,
       it might be harder than you think to fake a result file.

       Since some workunits are sent out more than once, SETI@home can
       detect errors by comparing the results. During the time of the
       project, the sky will be scanned several times. It's very
       unlikely that a cheater would get a workunit from the same
       location in the sky more than once.

2.7    SETI@home keeps getting a 'Bad Header' error. What can I do?

       1st Possibility
       First close the SETI@home client. Open the work_unit.sah file in
       the SETI@home directory and delete all the lines that appear
       before the 'type=work unit' line, but do not delete this line.
       Save the work unit file then restart the SETI@home client.

       2nd Possibility
       If you installed the client software from the FreeBSD ports
       collection, install the highest numbered version available from:
       If you then get an error with, go to /usr/src/lib/compat
       and make, make install compat22.

       3rd Possibility
       There's a problem at Berkeley with the servers. Try again later.
       If you look closely at the GUI client while it returns, you might
       or not might see "all data sent". If that happens, then the
       results were sent back allright. If you did not see that, then
       you can try to use the following to get a new workunit.

       Close SETI@home. Make sure it is closed, right click the icon in
       the systray and exit the client.

       Go to the SETI@home folder. Move the files "outfile.sah" and
       "result.sah" to a temporary folder.

       Start SETI@home. The client should get a new workunit. If this
       does not work and you get bad header again, then the problem is
       probably one of the other possibilities.

       When you wan't to try to send the results back again for the
       workunit that got the bad header error, then:

       Exit the client.

       Move the text files "work_unit.sah", "result_header.sah",
       "outfile.sah" and "state.sah" to another temporary folder. Move
       back the files from the first temporary folders.

       Start notepad, select save as, move to the SETI@home folder
       (usually c:\program files\SETI@home), save the file as
       "stop_after_send.txt". Start SETI@home. The results should be
       sent now. Exit SETI@home and delete the files "result.sah",
       "outfile.sah" and "stop_after_send.txt". You can now move back
       the files you moved to the temporary folder.

       If you are unsure which files should be moved away, then move all
       the text files.

2.8    Suddenly, without warning my system crashes - what should I do?

       Make sure you have the latest video (try first) and peripheral
       drivers for your system. This is often the cause of lockups and
       crashes, at least for Win9x.

       If your machine suddenly reboots itself or you get a blue
       screen, then it could be that the processor or some other
       part of your computer is overheating. Check that you have
       enough cooling for your processor. Most new computers have
       built in sensors for measuring the temperature of various
       parts in your computer.

2.9    I can't see the new WUs I've processed in the status area. Have
       they been registered at SETI@home?

       Probably. Sometimes you first get Stats at next WU. You can also
       check with the personal stats available at the SETI@home website
       ( Those stats are currently
       updated almost immediately so they should be the most accurate.

2.10   I want to run the text-client as a service in NT - how do I do

       Method nr.1

       You need to be administrator to do it. The easiest way is if you
       have IE4 or IE5 and Task Scheduler. It comes with IE5 and is an
       option in IE4. Set up a task to run when your PC boots to launch
       it. When you boot your PC, let it sit at the logon screen for 30
       seconds or so to verify the Task Scheduler service has started
       and it has launched the task. Now it will run in the background
       and the only way to stop it is with kill.exe from the NT resource

       If you don't have IE4/5, then use the Schedule Service built into
       NT, but you have to be an administrator to do this. Make sure it
       is set to run and log on as you. Then schedule it to run in about
       2 minutes using the AT command. Type AT /? from a command prompt
       for help. You do NOT want to use the /interactive switch. It will
       then run in the background. This is easier to use if you have the
       Resource Kit as well because you could use the SOON.EXE command
       in a batch file in your startup group.

       *Note: You must run the seti client manually the first time to
       configure it. Afterwards you may allow it to start automatically.

       Method nr.2 provided by Peter Yackel:

       You need two files from the NT resource kit: srvany.exe and
       instsrv.exe. You'll use these files to install SETI as a service.
       Here's the procedure:
       Copy srvany.exe to the SETI@home directory.  (I'll use c:\seti
       in this example.  I also assume the seti executable to have
       been renamed to seti.exe)

       Copy instsrv.exe to the winnt directory.
       Click Start, Run, and type "cmd" to open a DOS window.
       Type: instsrv SETI c:\seti\srvany.exe
       Type "exit" to return to NT
       Click Start, Run, and type "regedit"
       Go to the following registry key:


       Expand it by clicking the +

       Highlight SETI, then right click and select New, Key

       Type: Parameters

       Highlight Parameters, right click and add the following New
       String Values Names:


       Now double-click the Application value name you just created
       and enter the following Value Data:


       Do the same for AppDirectory but enter c:\seti for the Value

       Exit the Registry Editor.

       Go to Control Panel and double-click Services.

       Go to SETI and double-click on it.

       Set the startup to Automatic. Click OK. This will cause the
       service to automatically start at the next boot.

       To start the service immediately, highlight Seti and click Start.

       *Note: You must run the seti client once manually to configure
       it. Afterwards you may allow it to start through services.

       Method nr. 3

       Use a third party utility. (See 4.2.11)

2.11   Can I run the client invisibly on Win95/98?

       Nr 1.
       This has been found to work in the past but has failed with some
       Client/OS configurations.

       Before you do this, please bear in mind that you have to have
       permission to run SETI@home on the computer. Do not use this
       method to run SETI@home on other's computers. It is a violation
       of the license agreement to run SETI@home on computers you do not
       have permission to run SETI@home on.

       Install and setup the client in the normal way. After you have
       completed the setup of the client making sure that it is running
       all of the time and not just in screen saver mode. Run regedit
       and search for SETI@home It will probably be in there more than
       once, so the one you are looking for looks like this:

       seticlient    C:\Program Files\SETI@home\SETI@home.exe -min

       This string value will be in the key Run. Move it to the
       RunServices Key and remove it from the Run key Restart and the
       next time it comes up it will run even before you log in with no
       icon visible.

       Nr 2.
       This method works well with the Command Line version and Win 98.

       SetiLog is a third party utility that creates and maintains a
       file of completed work units. It can be used in conjunction with
       SetiWatch to monitor the progress of the client.

       Use SetiLog to start the client using the command line switch /H
       This will start the client hidden.

       Once the client starts and runs with this method create a
       shortcut to SetiLog in the Start Up folder.

       The client should now start on boot and run invisibly. In order
       to shut down the client you will have to ctrl-alt-del and select

       You can also create a registry entry to start the client
       automatically. I had to use the Shortcut to start SetiLog instead
       of the path directly to SetiLog. The registry entry should go in
       and can be named anything, but should contain the value of the
       path to the Shortcut to SetiLog, not the path to SetiLog.

       Other third party utilities may also have options to start the
       clients invisibly.

2.12   Sometimes the size of the workunit.txt file differs in size.
       Sometimes it's 340, sometimes 341, and yet other times 351. Is
       there something wrong?

       The difference between 340k and 341k is most likely a difference
       in the number of telescope position strings reported in the
       header.  The 351k is an benign bug in the portion of the splitter
       which determines where the work unit ends.  It basically tags on
       an extra 10.67k (IIRC) of data, that the SETI@home client
       ignores.  It has to do with the timing relationship between
       position information from the telescope and the start of a block
       on the tape.  All of the data in the work unit is still OK.

2.13   I don't have a permanent Internet connection, and have to pay for
       all my phone calls and net usage. Can I run SETI@home without
       going bankrupt?

       SETI@home will only connect to the Internet when you want it to.
       The GUI (slow, pretty graphics) clients have an option under
       "Preferences" to "Ask me before connecting to the Internet", and
       the CL (fast, no graphics) clients have a switch
       "-stop_after_process". In each case, this will prevent an
       internet connection being made until you're ready, and means the
       clients can be left safely unattended. When you are ready to
       connect to the Internet (say, for a normal browsing, usenet or
       mail session) you can make the client send results and retrieve a
       new Work Unit. In the GUI case, it will ask you to make a
       connection. For the CL client, stop the process, then restart it
       without the "-stop" switch, and it will connect automatically.
       Depending on the load at the Berkeley servers, within 5 minutes
       you will have sent your results and received new work to do.

       Programs have been developed, that will buffer the WU's for you,
       see sections 3 and 4.

       If you are still concerned that the clients will connect when you
       don't expect, make sure your system is configured *not* to
       connect "on demand" without prompting you for confirmation (a
       good idea anyway if you are concerned about unwanted
       connections), switch off your (external) modem, or pull the
       telephone plug from the socket (internal modem).

2.14   I already run the RC5-64 client. Can I run
       SETI@home as well, or do I have to choose which project to

       Both clients can run simultaneously. In screen-saver mode the
       SETI@home client seems to take priority. For those that don't
       allow the clients to connect automatically, the advantage is that
       the RC5-64 client can download multiple blocks to work on as
       opposed to SETI@home's single work unit. This means that while
       the SETI@home client waits for you to connect next, the RC5-64
       client can continue working on its own tasks.

2.15   What happened to the gaussian information display in the new Mac
       and Windows clients? The client is finding gaussians with lower
       fits, do the 2.x clients find more aliens or something?

       The 2.x GUI clients introduced new gaussian curve fitting
       graphics. To not make the new display blank all the time,
       SETI@home decided that the client should show all gaussians
       found, no matter how weak they were. The gaussian power is lower
       than in 1.x, too low to be reported back to SETI@home.

       The 3.x clients alternate between gaussians, pulses and triplets.

2.16   Can I run SETI@home 24/7 if I don't have a permanent Internet

       There are a couple of ways of running multiple instances of
       SETI@home such that, if one instance finishes its Work Unit,
       another will take over, so making sure that your system is
       working flat out most of the time.

       Under Windows 98/NT/2000 Command Line (non-graphic), and various
       *ix flavours, multiple clients in different directories may be
       "chained" to run consecutively by specifying the
       "-stop_after_process" switch for each. When one Work Unit is
       finished, that client will stop and another will take over. When
       all clients are done, an Internet connection can be made to send
       all results and receive new Work Units. The process may then be

       Also, there's the possibility of using one of the WU caching
       add-ons, such as SETIBuf or SETI Manager for Windows, SETI Unit
       Manager for Mac, or Hiram Clawson's RunCache & FetchCache for
       Unix like systems (for example Linux). See section 3 and 4.

       Running several clients simultaneously on a single-processor
       machine, or running more clients simultanesouly than the number
       of CPU's in your machine is not recomended, running them after
       eachother will give you better performance.

2.17   Is this bad for my processor, or my harddrive?

       Most technicians agree that turning the computer on and off is
       worse for the lifespan of the parts inside, than leaving it
       running. Of course most computers are obsolete long before the
       processor gives out, even when it's being run all the time. Your
       processor might get a little warmer, but not dangerously so,
       except if it has already been overclocked.

       If you are worried, make sure that your computer has sufficient

2.18   Does it use up a lot of electricity? Is this costing me money, or
       doing damage to the environment?

       Many SETI@home users would have been leaving the computer on
       anyway. For some computers, starting it up uses as much
       electricity as running it for a while anyway. With the monitor
       turned off, the average computer uses less electricity than a box
       fan, more along the same lines as a bright light bulb. Even less
       for laptops. Odds are running SETI@home all night while you are
       sleeping costs you a few pennies a day at most, and probably
       less. The millions of people whose computers are on to run this,
       who wouldn't have had them on otherwise, are adding a tiny
       fraction of a percent to the energy usage of the world -- not
       enough to have a measurable environmental impact. But turn that
       monitor off, when you're not using it. It probably uses more
       electricity than the rest of the system put together.
       The harddrive is not likely to take any damage either, as the S@H
       software only accesses the HD at most every 60 seconds.

2.19   How can I keep appraised of what's going on lately?

       Read the SETI@home web site at: and especially where news
       about the software is posted. Also you should check out the links
       at the bottom.

       Alt.sci.seti and sci.astro.seti are also good newsgroups to read
       since members from the SETI@home team posts there quite often.

       Look for posts by Matt Lebofsky and Eric J. Korpela, they're part
       of the SETI@home 'staff'.

       Also, look for posts by Hiram Clawson

       Hiram manages the UNIX porters and maintains the page containing
       the command line clients,

       "I am merely a volunteer at the edge of the project, not part
       of the SETI core team, although I do have a relationship with
       the team.  I was also one of the members/programmers of the first
       SERENDIP team in 1974/75 at Berkeley."

2.20   General CL client issues

2.20.1 What is the CL client?

       The Command Line client is a version of the SETI@home client that
       completely lacks pretty graphics and looks just like a DOS
       program. Because of that, it is also faster.

2.20.2 What CL options are there?

       Just start the client with a bogus option such as '-help' and it
       will tell you.

2.20.3 HELP, it stops at baseline smoothing!!!

       Version 2.4 of the commandline client is 'quiet' during
       processing. It still processes the data, but it doesn't tell you.
       You can use some of the add-on programs (section 3) to check up
       on the client, or you can give the -verbose option to the client

2.20.4 How can I check up on the client to see how it's doing, if it has
       found any signals, etc?

       You can either examine the .sah files, or use one of the third
       party add on programs, found later in this FAQ.

2.20.5 How do I tell the CL client to use a proxy?

       You start the client with the command line option
       -proxy proxyserver:port

       For example

       seti.exe -proxy

       where seti.exe is the name of the CL client.

2.20.6 I just found a bug in the -stop_after_ switches!!!

       No you didn't. Here's what they do:


       The client will process the current workunit, then exit. If the
       client has already processed a workunit, but you haven't sent it
       yet, then the client will send the results, fetch a workunit and
       process that workunit and _then_ stop.

       work_unit.sah present:       Process workunit, delete

       work_unit.sah not present:   Get new workunit, process workunit,
                                    delete work_unit.sah


       The client will send in the results AND retrieve a new workunit.
       If work_unit.sah is present, it will do nothing.


       If this file is present in the current directory, the client will
       SEND ONLY when it connects to the server. Delete the file if you
       want to get a new workunit, and create the file if you want the
       client to not get another workunit the next time it connects.
       The stop_after_send.txt file is empty. Works with the GUI client

       The presence of this file will not prevent the client from
       processing a workunit, if there is one in the directory.


       work_unit.sah and result.sah will never exist in the same
       directory at the same time. If you're making some scripts for
       managing the clients, you can use this fact for retrieving info
       about the current status of the processing in a directory.

2.21   Running the CL client on Windows

       This sections purpose is to give a short guide on how to run the
       command line client on windows.

2.21.1 What client should I download for Windows 95/98/2000/NT?

       There are currently two clients available:
       i386-winnt-cmdline.exe for Intel processors
       alpha-winnt-cmdline.exe for Alpha processors

       The clients are at

       Despite the name 'winnt', the clients will run on Windows 95, 98,
       2000 and Windows NT. For Windows 95, you have to download the
       Winsock 2 upgrade. You can get it from Microsoft:

       According to posts by hiramc@sco.COM to the seti newsgroups, the
       i386 client detects the processor it runs on and optimizes to it.
       Since some processors do not work well with that, an i486 version
       was compiled, optimized for 486 processors. Some Cyrix and AMD
       processors have troubble with the i386 client.

       Rumors tell it that there's very little performance difference
       between the two clients. Some say the i486 is faster, some say
       the i386.

       If the i386 client crashes your computer, try the i486 instead.

2.21.2 How do I start it?

       Every client should have its own directory, you can't run the CL
       client in the same directory as the GUI client.

       Starting the CL client can be as simple as double-clicking on the
       exe file from Windows Explorer, a window will then pop up and ask
       you a few questions if it's the first time you run it.

       To pass options to it, you normally start an MSDOS window and
       start the program from there. If you can't find DOS from the
       start menu, click start, run and type in That should
       bring up a CLI (command line interface). For ease of use, I
       suggest you rename the setiathome executable to something that's
       short and easy to type, like 'seti.exe' (without the quotes).

       Once you have to MS-DOS window in front of you, navigate your way
       through the directory structure by using the CD command.

       In this example, we'll pretend that the client is installed in
       F:\seti. To get there, you first type f: and press enter. Don't
       forget the colon. Then, it might be that the screen looks like


       Now you type cd.. (yes, two points at the end).

       This will bring you to


       Now you type cd seti
       and should now be in the seti directory.

       If you've renamed the executable to seti.exe you'd type something
       like this

       seti -verbose -stop_after_process

2.21.3 How do I stop it?

       You press two keys simultanesouly, the keys are CTRL and C.
       So, just press CTRL-C and the client will stop. As easy as that!

       Some of the add on programs can handle the starting and stopping
       of the CL client for you.

2.21.4 How do I make Windows 2000 autoconnect?

       Solution taken from a post by "Jedi"

       Goto Network and Dial Up Connections
       Under Advanced - Dial Up Preferences - Auto Dial
              Enable Current Locations
              Uncheck Always ask before
              Uncheck Disable For Current Session

       Goto Services
              Set Remote Access AutoConnection Manager to Automatic
              Set Remote Access Connection Manager to Automatic

       As is the norm with Windows, you must now reboot for this to take
       effect. For immediate results, you can manually start these

2.21.5 Do I have to uninstall the screen saver version if I use the CL

       No, but running both at the same time will give you worse WU
       throuput per day than running only one client at a time. An
       exception to this is computers that have more than one CPU's,
       then running one client for each processor is the most optimal.

       The CL client can not continue on a work unit that the GUI
       version has started on but not finished, likewise the GUI client
       can not continue on a work unit that the CL client has started to
       process. If you try to make them do that, they'll start over from
       0 %. So, don't have the CL client and GUI client installed in the
       same directory.

2.22   A short guide for the Linux newbie trying to run the SETI@home

       Many people seem to try a Linux distribution these days,
       including running SETI@home on it. This section answers some of
       the most common questions asked in the SETI newsgroups.

2.22.1 What client should I download?

       If you're using a newer Linux distribution, you'll probably want
       to download one of the gnulibc2.1 clients. Some older
       distributions might not work with those two clients, in that
       case, download one of the gnulibc1-static clients instead.

       If you've got a Pentium Pro, Pentium II, Pentium III, Celeron or
       AMD Athlon, the i686 clients will work on your machine (and will
       probably run slightly faster too.)

       All processors older than those mentioned above are usually not
       686 processors, a common mistake is to think the the AMD K6/K7 is
       a 686 processor. It is not, use the i386 client instead.

2.22.2 How do I uncompress the .tar file?

       You type tar -xvf filename.tar
       Where filename.tar is the name of the 'tarball' you want to
       uncompress. Uncompressing the file creates a directory of the
       same name. Within that directory will be the executable also
       with the same name. Many rename the executable to setiathome or
       simply seti.

2.22.3 How do I start it?

       You navigate to the directory where you've got the setiathome
       client, then type './filename' (without the quotes, where filename
       is the name of the executable). The ./ is important so that linux
       knows you want to run something in the current directory.

2.22.4 How do I stop it?

       If you've got it running in a console or Xterm, just press

       If you started the client in the background you should use:
       kill `cat /path/to/seti/pid.sah`

       You can also follow the instructions in the readme file that
       comes with the client. The instructions in it are quite easy to
       follow and it even works too!

       Some third party add ons can handle the starting and stopping of
       the client for you, and are highly recommended.

2.22.5 How can I run it in the background rather than in a window?

       Start the client with the options to direct output to /dev/null
       and use the switch & to release the command window. i.e.

       ./setiathome > /dev/null &

2.22.6 How can I have it automatically restart if it dies?

       You can ensure that it is always running by creating a cron job
       to start it. If it is already running then the cron job will not
       start an additional instance. It will only start the client if
       it is no longer running. My cron entry is in /etc/crontab and
       looks like this:

       30 * * * * mark cd /home/mark/Seti@home; ./setiathome > /dev/null &

       The user (mark in this example) must be allowed to use cron processes
       by an entry in the /etc/cron.allow file.

2.22.7 What is 'nice' and how do I set it?

       Mama said "Always be nice."

       Nice is the unix term for priority. A process that is nice will use
       the available processor but will give way to other processes that
       are not so nice. The range of nice is -20 to 19 (depending on
       your distribution. Negative numbers have the higher priority and
       positive numbers have a lower priority. You can set the niceness
       of the client with the -nice parameter.

       ./setiathome -nice 19

2.23   Why does the client timeout before windows has dialed my ISP?

       The SETI@home client does not set a timeout delay, it's windows
       that does this. Unfortunately, Microsoft has set this value too
       low so that you get a timeout before your modem has dialed your
       ISP and logged on.

       You can hope that the next patch from Microsoft will fix this, or
       use one of the excellent WU buffering/caching programs available,
       some mentioned in this FAQ and on SETI@Home's link page.

2.24   I just got a gaussian with a score of 0.30 and power 1.2, is this

       Considering that the SETI@home client does not record and report
       back gaussians with a power as low as that, the answer should be

       There has been some discussion in the newsgroup about what is an
       interesting gaussian and what is not. First of all, the client
       shows you on screen the best gaussian found so far based solely
       on the score it has, this value is also stored in state.sah and
       used by many add-ons. Gaussian score is calculated as power/fit
       and spike score as log10(power/40).

       The score is not good enough for determining if the gaussian is
       interesting, since its power might be way too low. The gaussians
       that the SETI@home client sends back to Berkeley are much more
       interesting, these are recorded in outfile.sah and result.sah.

       To see if the client has recorded a gaussian, open outfile.sah
       or result.sah and check for lines beginning with "gaussian:"
       (without the quotes). If such lines are present, the SETI@Home
       client has recorded the gaussian and will report it back to
       Berkeley. If you use windows, then you might have to use
       'Wordpad' or 'quickview' instead of Notepad, since Notepad has
       some problems with the format used in .sah files.

       So, what are the requirements for a gaussian to be recorded and
       reported by the client? First of all, the fit has to be lower
       than 8.8 (10 in versions 2.XX and below), this is always the same.
       The power is a bit more tricky, here's what Eric J. Korpela said:

       >If thats the case, why is the top gaussians page full of entries
       >with powers less than 3.2?  Are we talking different units of

       Yes, I had forgotten that our threshold is 3.2 in units of what
       we call "true mean power" and is integrated over the gaussian,
       whereas the reported power is the peak power or the gaussian.  So
       the conversion between true mean power units and the reported
       units depends upon the width of the gaussian.

       Roelof Engelbrecht seems to have found out in his latest
       version of SETISpy how the SETI@home client determines whether it
       should send back a gaussian or not. The magic formula is:

       (peak / mean) > 3.2

       In state.sah, that is bg_power / bg_true_mean. In result.sah and
       outfile.sah, it's peak / mean. Note that mean=7.283651e-01 is
       0.7283651, not 7.283651. The fit is called bg_chisq in state.sah.

       The criteria is also mentioned in SETI@home's science paper:

       It says "In order to confuse and obfuscate the public, we
       utilize substantial technical jargon", luckily Roelof
       Engelbrecht has translated this for us mortals in his excellent
       SETISpy add-on. See section 3.3.

2.25   I looked at my stats of returned units at SETI@home's webpage,
       the top gaussian I got for the last unit is missing, why?

       The top-gaussian is not the same as what is returned to
       SETI@home, see 2.24. This goes for spikes too.

       There's an add-on, called SETI Monitor, that provides information
       on all returned gaussians and spikes. See section 3.8.

2.26   My email address is about to change, what do I do?

       Go to the SETI@home web page. There's a tool there that allows
       you to change your email address. You'll need access to your old
       email address as you need a password to change the email address.

       When you've changed the email address, you need to tell the
       SETI@home client to use the new one. With the GUI clients, you
       can do this from the settings menu. Make sure you don't create a
       new account, but log in to an existing one. The commandline
       clients have a switch for this, -login.

       If you have already created a new account with your new email
       address instead of changing it, you can't transfer the credits
       from your old email address to your new one.

2.27   Re-ordered to 2.30 (10-5-2000)
       Was: What is an interesting pulse/triplet?

2.28   Why does the new client (3.X) take more time to complete a WU?

       Because more science is done. The client now searches a wider
       range of drift rates, from -50Hz to +50Hz. The client also
       searches for pulsed signals.

2.29   What are pulses and triplets?

       In the contexts of SETI@home, they are spikes that are repeated
       many times. Triplet means that there are three evenly spaced
       spikes. The triplet detection takes very little time to do, but
       it can only detect strong signals.

       The pulse finding algorithm can find very weak pulses, the more
       pulses the better the algorithm can find them. The pulse seeking,
       however, takes alot more time to do.

2.30   What is an interesting pulse/triplet? (re-ordered: was 2.27)

       For Pulses, the threshold is at a score of 1.0. A score of 1.04
       means that the pulse is twice as unlikely to be caused by random

       For triplets, the threshold is at a score of 7.75.

2.31   Why do certain WU's take longer to process?

       The Arecibo radio observatory can track stars to a certain
       degree, even if it's basically a big hole in the ground. If the
       telescope is moving more slowly, you get more data from a smaller
       area of the sky, simply more time on one target. This makes it
       possible for the pulse finding algorithm to use a larger chunk of
       the WU data at a time, making it more sensitive to possible
       pulses received.

2.32   Why are the most pulse searches done at a chirp rate of 0?

       Shorter pulses have a larger bandwidth, and therefore less
       affected by doppler shift. This is why you don't have to search
       for pulses at an FFT length of 128 and chirp of 2.3Hz, for

2.33   There's something strange with the power reported on pulses in
       outfile.sah vs. state.sah?

       Yes, the power is measured differently, here's a post by Eric
       Korpela of SETI@home explaining it:

       This part is actually by design.  The internal value of the pulse
       power if the peak power measured from the zero point.  The
       reported value is the peak power measured from the mean power.
       Since they are both normalized to the mean power, the reported
       power should be always 1.0000 less than the value in the state
       file.  Sorry for the confusion.

2.34   Is the first half of the pulse graph identical to the second?

       Yes, this is because of how the pulse finding algorithm works.
       Since the number of pulses could be over 2000, it's impossible to
       draw a graph of the entire duration of the pulses (they do this
       with the gaussian graph), so they draw the result of the folding
       algorithm twice to make it look periodical.

       Here's a description taken from a post by Eric Korpela of


       The pulse finding algorithm works like this (in general, not
       quite in detail):
       The algorithm is called a folding algorithm.  Suppose we have a
       data stream of 66 points that looks like this:


       The folding algorithm looks first for things with a period of N/3
       or 22 samples by adding up the points in groups of 22


       Now we look in this folded stream for an event above a threshold.
       If there was a strong signal with a period of 22 samples, the
       peaks from those signals would line up and  we would see a peak
       in the folded array.  Now we take the folded array and fold it in
       half again to get a period of 11 samples:


       And we look for peaks above a threshold.  And again to get an
       (average) period of 5.5 samples (it gets tricky with non-integer
       periods, and I'm really not attempting to do a good explanation
       of this part)


       And again to get a period of 2.75
        6  8  7
        4  6  3
       10 14 10

         Then we go back to the original data and search on a slightly
       smaller period, in this case 21+2/3 ~= 21.6667.  We do this by
       shifing our end point by one sample.

       Here's the original data again:


       Here's the samples we add together, note the last row was shifted
       by one.


       Now we fold that in half to search on a period of (21+2/3)/2 or
       about 10.83333


       And so on.  And so on.

       For a given array of length N, we search periods of

       N/(3*2^n) to N/(4*2^n) in period steps of 1/(3*2^n)
         with n=0 to log_2(N/3)-1

       N/(4*2^n) to N/(5*2^n) in period steps of 1/(4*2^n)
        with n=0 to log_2(N/4)-1

       N/(5*2^n) to N/(6*2^n) in period steps of 1/(5*2^n)
        with n=0 to log_2(N/5)-1

       In principle, you could go on from there to N/(6*2^n) and onward,
       but you've reached a point of diminishing returns, most of the
       periods you would search would have already been covered.  You
       only gain in sensitivity to pulse duration much smaller than the
       sampling rate, and since SETI@home is designed to be insensitive
       to things with large bandwidth, we probably wouldn't detect
       signals of that short a duration anyway.


       What you see on the graphics in the new S@H client is the folded

3      Third-party software

3.1    JSETITracker

       By James Birchfield

3.1.1  Programmer's comments

       JSETITracker is an add-on client for the SETI@home project
       software. It provides a vast array of information that is either
       not found in the SETI@home software, or is hard to find.
       JSETITracker, in addition, provides logging of all work units,
       and two different visualization methods to view your data. The
       first and simplest is the SkyMap. The SkyMap plots each work unit
       against a whole sky map to show you where your work units have
       come from. Each work unit shown is selectable and information
       about each is readily available with the click of a mouse. The
       second is a JSETITracker exclusive, CoordinateTracker.
       CoordinateTracker requests the detailed image of the area of sky
       that the work unit was recorded from SkyView, a NASA website. The
       image is then placed on the CoordinateTracker panel, and the work
       unit's coordinates are plotted on top of this image. This
       provides the user with a detailed path that the work unit
       followed as the receiver traveled along the sky. As the work unit
       processing progresses, a small square travels along the plotted
       line to indicate which part of the sky the current processing is
       currently looking at. The user may also at anytime choose anyone
       of the 20 or so coordinates and view their location in the sky
       with a different square.

       JSETITracker is written entirely in Java, and requires Java 1.1.6
       or higher, as well as JFC(Swing) 1.1 or higher. JSETITracker acts
       as a passive monitor to the 'state' files that the SETI@home
       software produces. It polls these files on a set interval and
       updates the display accordingly.

       JSETITracker has ben known to run successfully on a variety of
       Java enabled platforms including: Windows 95/98/NT, Linux,
       Solaris, OS/2, and Macintosh. JSETITracker should work on any
       other Java enabled platform as well.

       JSETITracker is deployed using Zero G's InstallAnywhereNow
       product. There are are platform specific installers for Windows
       95/98/NT, Macintosh, and Unix. There is also an 'other' installer
       for any other Java enabled platform. JSETITracker is also
       distributed as a single zip file that contains all the files
       necessary to run JSETITracker, including the JSETITracker .jar
       file and all associated images.

       JSETITracker is free to use by anyone.

       Get it:

3.2    Tk-SETI@home

       By Rick Macdonald

3.2.1  Programmer's comments

       TkSETI is a GUI front-end to the SETI@home client for UNIX. It is
       fully customizable with lots of cool features:

       Can passively monitor an already running SETIathome client.
       Can start/stop/pause the SETIathome client when TkSETI
       Can manually run/kill/pause/continue the SETIathome client.
       Can automatically stop the client during certain hours on certain
       Can run your dialup network start/stop scripts when the client
       needs to contact the server (even avoiding certain days and
       Restarts the client if it dies unexpectedly.
       Linux only: can automatically run/kill/pause/continue the
       SETIathome client based on system idleness by monitoring any
       devices such as keyboard, mouse, etc.
       Support for proxy servers.
       Tracks your personal best scores for big Spikes and Gaussians,
       and notifies you when new bigger ones are found.
       Displays your statistics such as work units processed, total CPU
       time, progress of current work unit, largest Spike and Gaussian,
       client CPU usage, etc.
       SkyMap shows the location of all work units processed plus the
       location of your best spike and gaussian.
       Fully configurable to run on any UNIX platform.
       Font selector.
       Lets you check the work statistics of your friends to see who is
       Notifies you if you or your friends make the Top Users, Spikes or
       Gaussians lists.
       Notifies you when a new version of TkSETI is available.

       Contact Rick Macdonald <> with any problems or
       enhancements ideas.

       TkSETI checks after every work unit for updates and notifies you
       when a new version is available. A window is popped up and also a
       message is placed in the TkSETI window manager title bar.

       The latest version is available from

3.2.2  Tk-SETI@home installation

       Untar the distribution file:
       gunzip -qc tkseti-1.38.tar.gz | tar xvf -
       and just place the tkseti file anywhere in your path.
       There is a "contrib" directory where various scripts and
       information has been contributed by TkSETI users.

       TkSETI requires Tcl/Tk 8.0 or newer.


3.2.3  Tk-SETI@home startup

       You must run the SETIathome client once manually from the command
       line to get registered. Just answer all the prompts. Once the
       client is running properly, you can run tkseti.

       TkSETI can be started if the client is already running, or it can
       start the client manually or automatically for you. This is
       explained in the Setup section that follows.

       TkSETI will look for the client files in the directory
       ~/setiathome. If you've run the client elsewhere, or run more
       than one client, just specify the setiathome client directory on
       the tkseti command line. For example:

       tkseti ~/setiathome

3.3    SETI Spy

       By Roelof Engelbrecht

3.3.1  Programmer's comments

       SETI Spy is a little program I wrote to "spy" on the progress and
       performance of the SETI@home client. I initially developed it for
       my own use, but I have decided to make it available to the
       general public free of charge.

       The graphical SETI@home client displays the progress and status
       of the analysis, but generating the graphics uses 60% or more of
       the available computing power. Some folks, including myself,
       would much rather use all of the available power to crunch data
       quicker than look at the pretty pictures. Enter a new type of
       software -- the SETI@home tracker -- that displays that progress
       an status of the analysis without having to generating the
       time-consuming graphics. There are some good SETI@home trackers
       available, but I wanted something to display the information I am
       interested in -- the progress and especially the performance of
       the SETI@home client. This is why I wrote SETI Spy.

       You can get SETI Spy at <>

3.3.2  Processing efficiency

       I developed SETI Spy to provide a tool that can be used to ensure
       that you are running your SETI@home client at peak efficiency.
       For benchmarking purposes I developed the following table of peak
       efficiencies from work unit speeds I measured and those reported
       on various news groups, bulletin boards, and web sites.

       Processor Peak Efficiency
       (cycles / FLOP)
       AMD K6                              10.0
       AMD K6-2                            11.0
       AMD K6-III                          10.5
       AMD Athlon                           8.5
       Intel 80486DX2                      18.0
       Intel Pentium                       12.0
       Intel Pentium MMX                    9.5
       Intel Pentium Pro                    8.5
       Intel Celeron                        8.5
       Intel Pentium II/III                 8.0
       Intel Pentium II/III Xeon (512kB L2) 7.5
       Intel Pentium II/III Xeon (1MB L2)   5.5
       Intel Pentium II/III Xeon (2MB L2)   5.0
       Sun Enterprise 4000                  5.0
       Sun Ultra 60                         5.2
       PowerMac G3                          6.5
       PowerMac G4                          4.5

       The peak efficiency of your processor depends on a number of
       factors, including:

       1. Floating Point Unit design

          Since most of the processing is done on floating point
          numbers, a very efficient Floating Point Unit (FPU) is
          essential for good performance. The Intel Pentium Pro,
          Celeron, Pentium II/III (Xeon), and AMD Athlon have pipelined
          FPUs which are more efficient than the non-pipelined FPUs of
          the other processors.

       2. Cache size and cache speed

          The most time-consuming part of SETI@home is the FFT routine
          which accesses a data set slightly larger than 512kB.
          Performance is much improved if this data set fits entirely in
          the L2 cache of the processor, as is the case for the 1MB and
          2MB Pentium II/III Xeons. In addition, the fast L2 cache like
          that of the Pentium II/III Xeon improves performance even

       3. Memory size and speed

          SETI@home requires about 16 MB of memory. The quicker it can
          access this memory, the faster it will run. Low latency memory
          will reduce the access time and speed up processing. Having at
          least 64 MB of physical memory will avoid swapping of the
          SETI@home code and data to slow virtual memory when running
          SETI@home together with other software.

       4. Operating system

          Some operating systems are more efficient than others. For
          example, a processor will be slightly more efficient under
          Windows NT than under Windows 95/98. Also, more efficient
          SETI@home clients exist for certain operating systems. For
          example, there is a Linux text client optimized for 686-class
          machines, but the Windows clients are optimized only for
          386-class machines.

       You can use the values in the table to determine if your
       SETI@home client is running at optimal efficiency. If your cycles
       / FLOP value is much higher than value in the table for your
       processor, you can probably improve your processing efficiency by
       using some of the tips in this FAQ.

       You can also use the values in the table to estimate the optimal
       work unit processing time for your processor, using the following

       Topt = 555 (CpF / MHz )


       Topt = Optimal WU processing time (hours)
       CpF = Cycles per FLOP (from table)
       MHz = processor speed in MHz

       For example, a 350 MHz Pentium II is expected to process one work
       unit in 555 (8.0 / 350) = 12.69 hours.

3.4    SETIWatch

       By Mark Loukko

3.4.1  What is SETIWatch?

       After using SETI@home for the last few months, I recently
       downloaded the command line version for NT. While the command
       line version is running it just displays the percentage
       completed. I wanted to know a little bit more, so I wrote a
       program called SETIWatch. It turns out if you're using the screen
       saver version of SETI@home you can also benefit from SETIWatch.
       SETIWatch has been tested on Windows NT and 98.

3.4.2  Some background

       On June 28, 1999 I released SETIWatch to the general public.
       Well, all I can say is WOW, I've been completely blown away by
       the response. So many people have sent me their complements and
       enhancement requests I've had a hard time keeping up. I've done
       my best to complete as many of the requests as I can.
       Unfortunately I do have a full time job and some enhancements
       will have to wait.

3.4.3  Where can I get it?

       Download it from this homepage:

3.4.4  How to install SETIWatch

       Place SETIWatch.exe into the same directory as SETI@home and run

3.5    SETILog

       By Mark Loukko

3.5.1  What is SETILog?

       Many people have ask me to include a way to record completed work
       units in SETIWatch. This task turned out to be a lot harder than
       I thought it would. I wanted a method that works every time, even
       when SETIWatch is not running. It turned out SETIWatch is not the
       place to capture completed work units. Instead, I developed a
       small (8k) program called SETILog.

3.5.2  How does SETILog work?

       The key to capturing a completed work unit is to run the command
       line version of SETI@home in a batch file. First SETI@home runs
       and then SETILog. This way we guarantee when a work unit
       completes we also log the results.

       When the work unit completes and SETILog runs, it grabs
       information about the work unit and places it into a csv (comma
       separated values) file called SETILog.csv. SETIWatch can read
       this file and displays the results in the "Completed Work Units"
       window. This csv file can even be loaded into Microsoft Excel,
       Access etc where you can do your own analysis if desired.

3.5.3  RunSETI.bat

       RunSETI.bat looks like this:
       seti.exe -stop_after_process
       if exist result.txt goto SaveLog
       if errorlevel -1073741510 goto Stop
       goto Start

       if errorlevel 0 SETILog.exe
       goto Start


       A couple of points regarding the batch file:

       1. Wondering what -1073741510 is for? Windows returns this number
          when Ctrl-C or Ctrl-Break is pressed.

       2. The file name for the command line version of SETI@home is
          quite long. Version 1.3 is
          "setiathome-1.3.i386-winnt-cmdline.exe" I find this a little
          tedious to type at the best of times! I've renamed my file to
          seti.exe This is what the above batch file refers to.

3.5.4  Where can I get it?

       Download it from this homepage:

3.5.5  How to Install SETILog

       Step 1. UnZip into the same directory as SETI@home.
       Step 2. Run the batch file!

3.6    SetiTEAM

       By Sqiz

3.6.1  Description

       Current Version 16th April 2000 = 1.6b

       SetiTEAM is free software for Windows 95+ downloadable from It requires no special
       installation, can use a standard internet connection or supports
       access via a proxy server.

       SetiTEAM interprets the team results and statistics pages on the
       SETI@home server to provide a more convenient interface with
       additional features and flexibility.

       SetiTEAM allows the team / statistics webpages for any group to
       be sorted (by Position, Name, WU's, Total or Average time), saved
       (in Word, Excel, HTML, Notepad, CSV or Clipboard formats),
       printed, or viewed as bar charts.

       In addition to remembering the previous session for use off-line
       as an aide memoir, results can now be saved for later comparison.
       This is useful to spot members joining / leaving teams and can
       highlight how different members are performing.

       The latest version also has a unique feature which allows you to
       predict the status of teams / members up to 3 months ahead. Lots
       of fun if you want to know when User A will overtake User B.

       Team founders can use a special mode to list the entire
       membership of the team along with all the Email addresses.

       Lots more features, including built in help with clickable links!

3.7    SETIBuf

       By Terry Lee

3.7.1  Legal notice and stuff

       SETIBuf is a set of *.bat files and instructions, created by
       Terry Lee. They are offered on an as-is basis without charge, and
       may be freely redistributed as long as the integrity of the
       installation package is preserved If you wish to distribute
       SETIBuf with modifications, please include the unaltered file along with your modifications in your own
       package, and call it anything other than SETIBuf.

       The batch files provided rely on SETIWatch and SETILog from Mark
       Loukko (because they are such nice tools!) However, instructions
       for doing the work unit buffering without using these programs
       are part of the SETIBuf.doc document.

       IMPORTANT:  The SETIAtHome command-line client will not run on
                   Windows 95. You must be running Windows 98, Windows
                   NT 4.0, or Windows 2000 in order to use the
                   command-line client or this procedure If you are
                   running Windows 95 and do not wish to upgrade, then
                   you can use only the SETIAtHome GUI (screen-saver)

                   (Note from the FAQ-maintainer, you CAN run the CL
                   client on Windows 95, see section 2.1.2 subsection 7)

3.7.2  General description

       One Work Unit (WU) is kept in each of the active 1 thru 9

       To keep one of the 1 through 9 folders from participating in the
       Work Unit cycle, rename the SETI.ok file it contains to
       To reactivate such a deactivated folder, rename the file
       to SETI.ok.  The original distribution files have folders 1 thru
       9 activated; if upgrading or reinstalling, this scheme retains
       the settings you currently have.  By renaming the SETI.ok/
       files in those folders according to the above scheme, you can
       control the size of your work unit buffer. WU
       sending/downloading/ processing will only be performed if there
       is a SETI.ok file present and there is not a file

       To stop a running SETI instance at any time:

       Restore the window if it is minimized
       Type CTRL+C
       Reply Y to the 'Terminate batch job (Y/N)?' prompt

       To stop processing on one WU and move on to the next WU

       Restore the window if it is minimized
       Type CTRL+C
       Reply N to the 'Terminate batch job (Y/N)?' prompt

       When you try to reboot a Win98 computer with a SETI instance
       running, you will get a message box advising you that Windows
       cannot stop the process.  Proceed as follows:

       Press the OK button.  The SETI window will restore if it is
       Type CTRL+C
       Reply Y to the 'Terminate batch job (Y/N)?' prompt

       Whenever SETI.bat is started, it first checks all the activated
       buffers, sending in any completed Work Units and replacing any
       sent in with new ones, and filling any empty buffers.  After all
       the activated buffers have been filled, it then begins processing
       at the point where processing was last interrupted.  If no
       process was interrupted, it begins with the lowest-numbered
       active folder. Whenever a WU is completed, all the activated
       buffers are checked again, and refilled as required.  Following
       the buffer filling, the WU processing resumes with the WU in the
       next activated folder. This way, the maximum number of work units
       will always be available.

       The AutoDial.ok file is a signal to SETI.bat that it should
       attempt to connect to SETIAtHome automatically when one or more
       of the WU buffers requires attention.  You can suppress this
       automatic connection by renaming it to  Automatic
       connection will be attempted if, and only if, both of the
       following conditionsare True:

       AutoDial.ok does exist in the SETI folder does not exist in the SETI folder

       If you disable automatic connection by deleting the AutoDial.ok
       file, instead of by the methods described above, then automatic
       connection attempts will be resumed by SETI.bat if you should
       ever upgrade or reinstall SETIBuf.

       If you have suppressed automatic connection with AutoDial.ok/, or if some of the automatic upload/download attempts
       have failed, you can try again without interruption of WU
       processing by invoking SETICall.  SETICall attempts to connect to
       SETIAtHome regardless of the AutoDial.ok/no settings.

       Additional processing scenarios are supported. See SETIBuf.doc
       for details.

       Multiple concurrent Work Units (for machines with multiple
       processors) are supported by SETIBuf Full instructions are
       included in SETIBuf.doc.

3.7.3  Where can I get it?

       SETIBuf is available from:

3.8    SETI Monitor

       By Lior Fainshil

3.8.1  Description

       SETI Monitor is a free add-on for SETI@home. It allows you to
       monitor the activity of your SETI@home client and see what it
       finds using almost no CPU power. SETI Monitor shows the signals
       found by your SETI@home client and saves information about
       completed work units. You can see the signals found in your
       current work unit, browse through previous results and see the
       totals. I used SETI@home for days with SETI Monitor and without
       it and couldn't see any difference in performance. SETI Monitor
       is highly optimized and its effect on performance is so
       insignificant that it is very hard to measure. SETI Monitor works
       with both the graphic and the text clients.

3.8.2  Some more details

       SETI Monitor reads the files created by SETI@home. Some of them
       contain the results which are going to be sent to the back
       server. SETI@home currently searches for two kinds of signals:
       spikes and gaussians. SETI Monitor shows these on a graph, where
       spikes are shown in red and gaussians in blue. This is in
       contrast to the other well known add-ons, which currently can
       show only the parameters of the best signal. If SETI Monitor is
       in memory when a work unit is completed, it automatically saves
       the results and allows you to review them later in the same way
       you see the current work unit. You can also see all the found
       signals from all work units on one graph.

       SETI Monitor has a few
       settings. You can set for example if SETI@home is loaded on
       startup. There are some hidden settings as well, which are
       configured automatically without causing troubles to the user
       with questions that only make things hard. It also has a very
       small and clean uninstaller.

       The best way to see what SETI Monitor is, is of course to look at
       the screenshots at

3.8.3  Where can I get it?

3.9    SETI UniT Manager

       By Vicksoft, Christian Vick

3.9.1  About SUM

       SETI UNiT Manager (SUM) is a very versatile add-on for the
       Macintosh client, and offer many features:

       * Buffering of workunits
              - automatic up-/downloads to adjustable times and...
              - automatic up-/downloads after an adjustable amount of 
          finished units or...
              - manually up-/downloads.

       * Independece of the SETI-Server:
              - no interrupts of crunching during times of bad
                connections to the SETI-Server.
              - offline crunching during  your 4-week vacation.
              - comfortable use of computers without
                internet-connectivity as SETI-workstations.

       * Automatically uses a Ramdisk, if present, to save your HD and
         make it less noisy. Optional backup to disk of the data.

       * Statistics includes CPU usage in percent, total time, crunch
         time, CPU time, all average times, all best/worse times and how
         many UNiTs have been crunched.

       * After sending results to the SETI-Server, SUM can take
         schreenshots of the current stats.

       * Can help you connect if you use certain ISP's that sends you
         advertisements first, regardless of what you requested.

       * Famechecker, checks your units against those on SETI@home's
         Top-20 page

3.9.2  Cost

       SUM donates 2% of your workunits to the "Magic Village Team",
       otherwise it's completely free.

3.9.3  Requirements

       * Mac OS 8.6 or 9.x. (8.5.x also, but check the SUM webpage)

       * Akua Sweets 1.3.6. or higher (

       * Optional: Text-to-Speech to let SUM speak.

3.9.4  Where can I get it?

3.10   Setimgr

       By Bernard Hatt

3.10.1 Programmer's comments

       Setimgr is a simple manager for the SETI@home clients on UNIX
       machines. It buffers work units, runs multiple instances on
       multiprocessor machines and outputs a primitive progress report.

       The latest version is 0.03a (BSD style license)

3.10.2 Setup

       Setimgr requires:
         * A setiathome client binary
         * A compiled setimgr binary
         * A setimgr.conf config file
         * A sub-directory for each buffered work unit (called proc[n])

       If there isn't a setimgr.conf in the current directory setimgr
       will output an example config file with the default values in it.

       Further details can be found in the readme file.

3.10.3 Operation

       Setimgr can either be setup (in the config file) for a permanent
       connection, where it will attempt to upload/download completed/
       new work units as soon as one is finished, or for dial-up
       connections it will wait until it receives SIGHUP to initiate

       Details of the config file and setup can be found on the web

3.11   Seti4Net

       Andre Starkloff is writing an application to monitor multiple
       machines on a net running Seti@home.

       You can monitor his progress at

3.12   Multi-SETI@home Monitor - Msetimon

       A graphical add-on package to monitor seti@home activity that
       may be running on multiple computers over a network or multiple
       instances on the same computer. Runs on Windows or Linux.

4      Homepages

       This document is more than a FAQ, below you'll find a few pages
       related to SETI and SETI@home. Consider is at as "guide" instead
       of answers in a FAQ.

       Dale's "Star Rating"
       "0"   = The Pits. Don't even bother going there.
       *     = If you don't have anything to do, well... maybe.
       **    = Interesting, but has room for improvement.
       ***   = Very nice site. Interesting, Informative, Could be
               spruced up a bit.
       ****  = Cool site. I was impressed. Go There. Be informed and
       ***** = Way To Do A Site! I'm Impressed! GO HERE!

4.1    Homepages concerning SETI@home

4.1.1  SETI@home home

       Reviewed by Dale Willamson

       This is the home-base of operations for the SETI@home scientific
       project. It's the official place where you can download the
       latest version of the processing client software, but it also has
       many interesting areas that are well worth checking out.
       Perhaps one of the more interesting aspects of the SETI@home Web
       site, is the "News and Statistics" sections. Here you can find
       some really interesting information presented in graphical form,
       concerning how many new volunteers are joining the search for ETI
       each day; The total so far, of work units processed by groups and
       individual volunteers; The top 20 "spikes" and "Gaussians" found
       so far; Graphs and Maps; an updated report on things relating to
       the project from storm threats, to hardware upgrades. You can
       even take the "SETI at Home Poll" and give your reasons for
       joining the search for ETI and also some of what your own
       opinions and thoughts might be about "ET"!

       As far as "looks" are concerned, it's a little "dark", but hey --
       these guys are "Scientists", and not necessarily polished at
       making a Web site look really, really cool! But then again, I'm
       glad they know what they're doing in searching for ET instead of
       great at putting those lame "flames" all over the place, aren't

       One other mention that I'd like to make, is that near the bottom
       of the Front page, you'll find a listing of those companies that
       have made some substantial donations to the SETI@home Project. If
       you can find the time, it wouldn't do any harm to log onto those
       donating companies and leave a message telling them that you
       appreciate the help they've given to this project. Though there
       are no strings attached to these donations they have given, any
       business likes to know that they are appreciated and this is a
       great way to show them. Too, you will also find there, a place
       where YOU can also make a donation to SETI@home. While they
       certainly appreciate everybody helping them process their
       collected data from the Aricebo Dish Antenna, they really need
       some money to help buy more equipment. So, if you could spare
       what it costs to go to a movie once, it would make quite a

4.1.2  SETIweb

       Reviewed by Dale Williamson

       Hosts the sci.astro.seti pages, where links can be submitted,
       and binaries can be posted, as the s.a.s. group do not permit

       Here it is:

       Stan Schonberg is the editor of these pages.

4.1.3  SETIforum

4.1.4  SETI @ SixDegrees

       Reviewed by Dale Willamson - Dale's Rating: **

       The above URL will take you to a very nice site created by Kris
       Johnson, however if you click on the Seti@SixDegrees button, you
       will get clobbered with some commercials, so be fore-warned. But,
       it _is_ an interesting site anyway. For most of the options, you
       do need to become a member, but I will note -- It Is Free! This
       is most definately a "Seti@Home" type of place, with some good
       starting points. I'll try to re-visit this place in a little bit
       and see how they've improved things.

4.1.5  SETI@home Speedup Tips

4.1.6  Derived statistics for SETI@home @ Rovingmouse


       Reviewed by Dale Willamson - Dale's Rating: **

       If you've got a MAC computer, check this site out. If you loose
       the pointer to it, just go to the SETI@home site and go to
       "Related Web Sites" and it'll be on the top of the list. Just
       "click" and you're there. It's even been rated as "Internet Site
       of The Month" by My Mac Magazine - Sept. 1999.

       It's got some "fun things" at SETI Station, as well as some
       serious stuff too, like learning how to speed up your MAC client
       processing by using RAM disk. There is even a Poll available to
       let them know what kind of MAC you're running. There's Tips,
       Teams, Winners & Loosers, and articles taken from various

       Though the site is a bit "dark", it is useful and informative. I
       didn't care too much for the pull-down windows, but to each his

4.1.8  SETI: The Drake Equation

4.1.9  Sci.astro FAQ about SETI

4.1.10 Team Canada

       Reviewed by Dale Willamson - Dale's Rating: ****

       I thought I'd mention a Seti "Team" site this time, just because
       I was struck by how nice the effort was done in putting this
       together. Some things just deserve a special mention when
       everything turns out so well. The "Team Canada" site is very
       attractively put together and is hosted by Andrew Turi.

       While there is always room for improvement, some great work was
       put into this site with just a few "reminders" that Canadians had
       something to do with it. <grin> If you go to their section called
       "What is Seti @ Home?", you'll find some media links to MSNBC,
       CNN, and Time coverage of the Seti@Home project, a pretty cool
       "Alien" creature created by a guy named Zombieman, and some Team
       newsletters which are maintained by Bob Page. It gives you the
       impression that these guys are serious about this project!

       The Team Canada site is pleasant to the eyes, not overly-done,
       but "classy". I like it, and think you will too. If you decide
       to stop by for a visit, leave them an email if for no other
       reason, to let them know what you thought about their site.

4.1.11 The Planetary Society

       Reviewed by Dale Williamson - Dale's Rating: ****1/2*

       Right from the start, this is obviously a highly rated site!
       It's well put together -- everything works -- and it's a great
       place to find scads of information. At the time of this writting,
       Planetfest '99 is going on with the Mars landing only 7 days
       away. There's a "Headline" section featuring the hotest current
       space science topics, and a "Special Sections" area where you
       can operate a rover from a classroom! They even have a very nice
       search engine for searching "seti" subjects.

       The Planetary Society is now in partnership with in
       France and is also accessible in Spanish!

       It's a nice site, like I mentioned at the top -- well put
       together and worth checking out.

4.1.12 Patch-free-Processing

       By Alfred Das

4.1.13 Sky & Telescope

       Reviewed by Dale Williamson - Dale's Rating: *****

       The Sky&Telescope site. What a pleasant and nicely done site!
       Full of interesting features such as Current News, News Archive,
       Special Reports, and you can cruise through their current monthly
       magazine on-line. Of interesting note, the site also features the
       artwork of Lynette Cook, a great artist, and there's a link to
       some of her artwork. Check that out as well when you visit here.
       (Don't forget to click on the "detail" hotlinks so you can see
       her pictures in larger detail, too.)

       Paying special attention to just one of the articles being shown
       when I visited this site, is a Dec 1998 article entitled "The
       Chance of Finding Aliens" and in it you'll find a reevaluated
       "Drake Equation" along with some interesting photos.

       All-in-all, this is a great site (or it wouldn't have my
       five-star rating), and is just loaded with interesting "stuff"!
       I was impressed and think you will be too!

4.1.14 SETI Institute

       (SETI Institute review:  8.04.2000)

       Reviewed by Michael Johnson - Michael's Rating: *****

       The SETI Institute is a non profit corperation that was founded
       in 1984, and serves as an institutional home for scientific and
       educational projects relevant to the nature, distribution, and
       prevalence of life in the universe.

       The website is very nicely laid out and easy to navigate.  Just
       about every topic imaginable that is related to SETI can be found
       here, including scientific and technological aspects of
       astronomy, planetary sciences, biological, chemical and cultural
       evolution.  Their primary focus is on conducting and encouraging
       public education on these topics.

       The site is not updated as frequently as I would like to see it,
       but I did enjoy breezing through the archives and reading some of
       the past news articles.  The FAQ page is very well done also, and
       answers most questions about the website and their mission.

       All in all, a wonderful website that I will visit should you.

4.1.15 SETI League

4.1.16 Removed (11 Feb 2001)

4.2    SETI utilities

4.2.1  SETIwatch & SETIlog

4.2.2  SETI Manager

4.2.3  TKSETI@home

4.2.4  SETISPY

4.2.5  JSETITracker

4.2.6  SetiTEAM Homepage

4.2.7  SETIBuf homepage

4.2.8  SETI Monitor homepage

4.2.9  SETI UNiT Manager homepage

4.2.10 RunCache & FetchCache

4.2.11 Seti@home Service

4.3    SETI fun

4.3.1  Carolyn's Clinic

       If you ever suffer from WU withdrawal or some other SETI@home
       related illnesses, visit the clinic. Wondering whether to
       overclock or not or what that science jargon in the Tech news
       means, the clinic will help you with that and just about anything
       else too.

5      Acknowledgements

5.1    Sci.astro FAQ

       From the sci.astro FAQ I have used section 1.2.2 and 1.2.3, and
       have hereby agreed to bring this copyright statement:

       Subject: Copyright

       This document, as a collection, is Copyright 1995, 1996, 1997 by
       T. Joseph W. Lazio (  The individual articles
       are copyright by the individual authors listed.  All rights are
       reserved. Permission to use, copy and distribute this unmodified
       document by any means and for any purpose EXCEPT PROFIT PURPOSES
       is hereby granted, provided that both the above Copyright notice
       and this permission notice appear in all copies of the FAQ
       itself.  Reproducing this FAQ by any means, included, but not
       limited to, printing, copying existing prints, publishing by
       electronic or other means, implies full agreement to the above
       non-profit-use clause, unless upon prior written permission of
       the authors.

       This FAQ is provided by the authors "as is," with all its faults.
       Any express or implied warranties, including, but not limited to,
       any implied warranties of merchantability, accuracy, or fitness
       for any particular purpose, are disclaimed.  If you use the
       information in this document, in any way, you do so at your own

5.2    People who have worked with the FAQ

       The current maintainer of the FAQ wishes to thank
       the following persons for their past and/or present
       work with the FAQ:

       Peter Alfredsen, who maintained the FAQ up to version 1.5.

       Walter Novacek who did the html porting up to version 1.30.

       Dale Williamson who handled the 4.x.x section until his computer
       broke down.

       Jan Knutar, who maintained the FAQ from version 1.5.2 to 1.9.8

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