SETI@home
Encyclopedia
SETI@home is an Internet-based public volunteer computing
project employing the BOINC
software platform, hosted by the Space Sciences Laboratory
, at the University of California, Berkeley
, in the United States
. SETI is an acronym for the Search for Extra-Terrestrial Intelligence
. Its purpose is to analyze radio signals, searching for signs of extra terrestrial intelligence, and is one of many activities undertaken as part of SETI
.
SETI@home was released to the public on May 17, 1999, making it the second large-scale use of distributed computing
over the Internet for research purposes, as Distributed.net
was launched in 1997. Along with MilkyWay@home
and Einstein@home
, it is the third major computing project of this type that has the investigation of phenomena in interstellar space as its primary purpose.
The second of these goals is generally considered to have succeeded completely. The current BOINC environment, a development of the original SETI@home, is providing support for many computationally intensive projects in a wide range of disciplines.
The first of these goals has failed to date: no evidence for ETI signals has been shown via SETI@home. However, ongoing continuation is predicated on the assumption that the observational analysis is not an 'ill-posed' one. The remainder of this article deals specifically with the original SETI@home observations/analysis.
transmissions from extraterrestrial intelligence using observational data from the Arecibo radio telescope
. The data is taken 'piggyback' or 'passively' while the telescope is used for other scientific programs. The data is digitized, stored, and sent to the SETI@home facility. The data is then parsed into small chunks in frequency and time, and analyzed, using software, to search for any signals—that is, variations which cannot be ascribed to noise, and contain information. The crux of SETI@home is to have each chunk of data, from the millions of chunks resulting, analyzed off-site by home computers, and then have the software results reported back. Thus what appears an onerous problem in data analysis is reduced to a reasonable one by aid from a large, Internet-based community.
The software searches for five types of signals that distinguish them from noise:
There are many variations on how an ETI signal may be affected by the interstellar medium, and by relative motion of its origin compared to Earth. The potential 'signal' is thus processed in a number of ways (although not testing all detection methods nor scenarios) to ensure the highest likelihood of distinguishing it from the scintillating noise already present in all directions of outer space. For instance, another planet is very likely to be moving at a speed and acceleration with respect to Earth, and that will shift the frequency, over time, of the potential 'signal'. Checking for this through processing is done, to an extent, in the SETI@home software.
The process is somewhat like tuning a radio
to various channels
, and looking at the signal strength meter. If the strength of the signal goes up, that gets attention. More technically, it involves a lot of digital signal processing, mostly discrete Fourier transform
s at various chirp
rates and durations.
.
While the project has not reached the stated primary goal of finding extraterrestrial intelligence, it has proved to the scientific community that distributed computing projects using Internet-connected computers can succeed as a viable analysis tool, and even beat the largest supercomputers. However, it has not been demonstrated that the order of magnitude excess in computers used, many outside the home (the original intent was to use 50,000-100,000 "home" computers), has benefited the project scientifically. (For more on this, see 'threats to project' below.)
Astronomer
Seth Shostak
stated in 2004 that he expects to get a conclusive signal and proof of alien contact between 2020 and 2025, based on the Drake equation
. This implies that a prolonged effort may benefit SETI@home, despite its (present) eleven-year run without success in ETI detection.
data.
Observational Data
is recorded on 36 Gigabyte
tapes at the Arecibo Observatory
in Puerto Rico
, each holding 15.5 hours of observations, which is then mailed to Berkeley
. Arecibo
does not have a high bandwidth
Internet connection, so data must go by postal mail
to Berkeley at first. Once there, it is divided in both time
and frequency domain
s work units of 107 seconds of data, or approximately 0.35 MB, which overlap in time but not in frequency. These work units then get sent from the SETI@home server
over the Internet
to personal computers around the world to analyze.
The analysis software can search for signals with about one-tenth the strength of those sought in previous surveys, because it makes use of a computationally intensive algorithm
called coherent integration that no one else has had the computing power to implement.
Data is merged into a database
using SETI@home computers in Berkeley. Interference
is rejected, and various pattern-detection algorithms are applied to search for the most interesting signals.
or continuously while a user works, making use of processor time that would otherwise be unused.
The initial software platform, now referred to as "SETI@home Classic", ran from May 17, 1999 to December 15, 2005. This program was only capable of running SETI@home; it was replaced by Berkeley Open Infrastructure for Network Computing
(BOINC), which also allows users to contribute to other distributed computing projects at the same time as running SETI@home. The BOINC platform will also allow testing for more types of signals.
The discontinuation of the SETI@home Classic platform has rendered older Macintosh
computers running pre-Mac OS X versions of the Mac OS
unsuitable for participating in the project.
SETI@home is available for the Sony PlayStation3 console.
On May 3, 2006 new work units for a new version of SETI@home called "SETI@home Enhanced" started distribution. Since computers now have the power for more computationally intensive work than when the project began, this new version is more sensitive by a factor of two with respect to Gaussian signals and to some kinds of pulsed signals than the original SETI@home (BOINC) software. This new application has been optimized to the point where it will run faster on some workunits than earlier versions. However, some workunits (the best workunits, scientifically speaking) will take significantly longer.
In addition, some distributions of the SETI@home applications have been optimized for a particular type of CPU. They are referred to as "optimized executables" and have been found to run faster on systems specific for that CPU. , most of these applications are optimized for Intel processors (and their corresponding instruction sets).
The results of the data processing are normally automatically transmitted when the computer is next connected to the Internet; it can also be instructed to connect to the Internet as needed.
operations. It is acknowledged by the Guinness World Records
as the largest computation in history. With over 278,832 active computers in the system (2.4 million total) in 234 countries, as of November 14, 2009, SETI@home has the ability to compute over 769 teraFLOPS. For comparison, the K computer
, which as of June 20, 2011 was the world's fastest
supercomputer
, achieved 8162 teraFLOPS.
in Australia
to analyse the southern hemisphere. However, as of March 9, 2009, these plans were not mentioned in the project's website. Other plans include a Multi-Beam Data Recorder, a Near Time Persistency Checker and Astropulse
(an application that uses coherent dedispersion to search for pulsed signals). Astropulse will team with the original Seti@Home to detect other sources, such as rapidly rotating pulsars, exploding primordial black holes, or as-yet unknown astrophysical phenomena. Beta testing of the final public release version of Astropulse was completed in July 2008 and the distribution of work units to higher spec machines capable of processing the more CPU intensive work units started in mid July 2008.
As with any competition, attempts have been made to 'cheat' the system and claim credit for work that has not been performed. To combat cheats, the SETI@Home system sends every workunit to multiple computers, a value known as "initial replication" (currently 2). Credit is only granted for each returned workunit once a minimum number of results have been returned and the results agree, a value known as "minimum quorum" (currently 2). If, due to computation errors or cheating by submitting false data, not enough results agree, more identical workunits are sent out until the minimum quorum can be reached. The final credit granted to all machines which returned the correct result is the same, and is the lowest of the values claimed by each machine. The claimed credit by each machine for an identical workunit often varies due to very minor differences in floating point arithmetic on different processors.
Some users have installed and run SETI@home on computers at their workplaces — an act known as
'Borging', after the assimilation-driven Borg of Star Trek
. In some cases, SETI@home users have misused company resources to gain work-unit results — with at least two individuals getting fired for running SETI@home on an enterprise production system. There is a thread in the newsgroup alt.sci.seti which bears the title "Anyone fired for SETI screensaver" and ran starting as early as September 14, 1999.
Other users collected large quantities of equipment together at home to create "SETI farms", which typically consist of a number of computers consisting of only a motherboard
, CPU
, RAM
and power supply
that are arranged on shelves as diskless workstations running either Linux
or old versions of Microsoft Windows
"headless" (without a monitor).
facility operated by the National Astronomy and Ionosphere Center and administered by Cornell University
.
The decreasing operating budget for the observatory has created a shortfall of funds which has not been made up from other sources such as private donors, NASA
, other foreign research institutions, nor private non-profit organizations such as SETI@home. The National Science Foundation
has made it clear that Arecibo will close in 2011 without such funds, and therefore the present data stream for SETI@home would cease in that situation.
However, in the overall longterm views held by many involved with the SETI project, any usable radio telescope could take over from Arecibo, as all the SETI systems are portable and relocatable.
As of October 16, 2005, approximately one third of the processing for the non-BOINC version of the software was performed on work or school based machines. As many of these computers will give reduced privileges to ordinary users, it is possible that much of this has been done by network administrator
s.
To some extent, this may be offset by better connectivity to home machines and increasing performance of home computers.
for SETI research, and private funding is always limited. Berkeley Space Science Lab has found ways of working with small budgets and the project has received donations allowing it to go well beyond its original planned duration, but it still has to compete for limited funds with other SETI projects and other space sciences projects.
In a December 16, 2007 plea for donations, SETI@home stated its present modest state and urged donations for $476,000 needed for continuation into 2008.
BOINC relies on cross-checking to validate data but unreliable clients need to be identified, to avoid situations when two of these report the same invalid data and therefore corrupt the database.
A very popular unofficial client allows users to take advantage special features provided by their processor(s) such as SSE
, SSE2
, SSE3
, SSSE3
and SSE4.1
to allow for faster processing. The only downside to this is that if the user selects features that their processor(s) do not support, the chances of bad results and crashes rise significantly. Tools are freely available to tell users what features are supported by their processor(s).
The project has had to shut down several times to change over to new databases capable of handing larger datasets. Hardware failure has proven to be a substantial source of project shutdowns—as hardware failure is often coupled with database corruption.
Project news (Oct 28, 2010)
Volunteer computing
Volunteer computing is a type of distributed computing in which computer owners donate their computing resources to one or more "projects".-History:...
project employing the BOINC
Berkeley Open Infrastructure for Network Computing
The Berkeley Open Infrastructure for Network Computing is an open source middleware system for volunteer and grid computing. It was originally developed to support the SETI@home project before it became useful as a platform for other distributed applications in areas as diverse as mathematics,...
software platform, hosted by the Space Sciences Laboratory
Space Sciences Laboratory
The Space Sciences Laboratory is an Organized Research Unit of the University of California, Berkeley. It is located in the Berkeley Hills above the university campus...
, at the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
, in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. SETI is an acronym for the Search for Extra-Terrestrial Intelligence
SETI
The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...
. Its purpose is to analyze radio signals, searching for signs of extra terrestrial intelligence, and is one of many activities undertaken as part of SETI
SETI
The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...
.
SETI@home was released to the public on May 17, 1999, making it the second large-scale use of distributed computing
Distributed computing
Distributed computing is a field of computer science that studies distributed systems. A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal...
over the Internet for research purposes, as Distributed.net
Distributed.net
distributed.net is a worldwide distributed computing effort that is attempting to solve large scale problems using otherwise idle CPU or GPU time. It is officially recognized as a non-profit organization under U.S...
was launched in 1997. Along with MilkyWay@home
MilkyWay@Home
MilkyWay@home is a volunteer distributed computing project in astrophysics running on the Berkeley Open Infrastructure for Network Computing platform...
and Einstein@home
Einstein@Home
Einstein@Home is a volunteer distributed computing project hosted by the University of Wisconsin–Milwaukee and the Max Planck Institute for Gravitational Physics . The project is directed by Bruce Allen...
, it is the third major computing project of this type that has the investigation of phenomena in interstellar space as its primary purpose.
Scientific research
The two original goals of SETI@home were:- to do useful scientific work by supporting an observational analysis to detect intelligent life outside Earth, and
- to prove the viability and practicality of the 'volunteer computing' concept.
The second of these goals is generally considered to have succeeded completely. The current BOINC environment, a development of the original SETI@home, is providing support for many computationally intensive projects in a wide range of disciplines.
The first of these goals has failed to date: no evidence for ETI signals has been shown via SETI@home. However, ongoing continuation is predicated on the assumption that the observational analysis is not an 'ill-posed' one. The remainder of this article deals specifically with the original SETI@home observations/analysis.
Procedure Details
SETI@home searches for possible evidence of radioRadio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
transmissions from extraterrestrial intelligence using observational data from the Arecibo radio telescope
Arecibo Observatory
The Arecibo Observatory is a radio telescope near the city of Arecibo in Puerto Rico. It is operated by SRI International under cooperative agreement with the National Science Foundation...
. The data is taken 'piggyback' or 'passively' while the telescope is used for other scientific programs. The data is digitized, stored, and sent to the SETI@home facility. The data is then parsed into small chunks in frequency and time, and analyzed, using software, to search for any signals—that is, variations which cannot be ascribed to noise, and contain information. The crux of SETI@home is to have each chunk of data, from the millions of chunks resulting, analyzed off-site by home computers, and then have the software results reported back. Thus what appears an onerous problem in data analysis is reduced to a reasonable one by aid from a large, Internet-based community.
The software searches for five types of signals that distinguish them from noise:
- Spikes in power spectra
- Gaussian rises and falls in transmission power, possibly representing the telescope beam's main lobeMain lobeThe main lobe, or main beam, of an antenna radiation pattern is the lobe containing the maximum power. This is the lobe that exhibits the greatest field strength....
passing over a radio source - Triplets — three power spikes in a row
- PulsingPulse (signal processing)In signal processing, the term pulse has the following meanings:#A rapid, transient change in the amplitude of a signal from a baseline value to a higher or lower value, followed by a rapid return to the baseline value....
signals that possibly represent a narrowbandNarrowbandIn radio, narrowband describes a channel in which the bandwidth of the message does not significantly exceed the channel's coherence bandwidth. It is a common misconception that narrowband refers to a channel which occupies only a "small" amount of space on the radio spectrum.The opposite of...
digital-style transmission - AutocorrelationAutocorrelationAutocorrelation is the cross-correlation of a signal with itself. Informally, it is the similarity between observations as a function of the time separation between them...
detects signal waveforms.
There are many variations on how an ETI signal may be affected by the interstellar medium, and by relative motion of its origin compared to Earth. The potential 'signal' is thus processed in a number of ways (although not testing all detection methods nor scenarios) to ensure the highest likelihood of distinguishing it from the scintillating noise already present in all directions of outer space. For instance, another planet is very likely to be moving at a speed and acceleration with respect to Earth, and that will shift the frequency, over time, of the potential 'signal'. Checking for this through processing is done, to an extent, in the SETI@home software.
The process is somewhat like tuning a radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
to various channels
Channel (communications)
In telecommunications and computer networking, a communication channel, or channel, refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel...
, and looking at the signal strength meter. If the strength of the signal goes up, that gets attention. More technically, it involves a lot of digital signal processing, mostly discrete Fourier transform
Discrete Fourier transform
In mathematics, the discrete Fourier transform is a specific kind of discrete transform, used in Fourier analysis. It transforms one function into another, which is called the frequency domain representation, or simply the DFT, of the original function...
s at various chirp
Chirp
A chirp is a signal in which the frequency increases or decreases with time. In some sources, the term chirp is used interchangeably with sweep signal. It is commonly used in sonar and radar, but has other applications, such as in spread spectrum communications...
rates and durations.
Results
To date, the project has not confirmed the detection of any ETI signals (see extraterrestrial intelligence). However, it has identified several candidate targets (sky positions), where the spike in intensity is not easily explained as noisespots, for further analysis. The most significant candidate signal to date was announced on September 1, 2004, named Radio source SHGb02+14aRadio source SHGb02+14a
Radio source SHGb02+14a is a source and a candidate in the Search for Extra-Terrestrial Intelligence , discovered in March 2003 by SETI@home and announced in New Scientist on September 1, 2004....
.
While the project has not reached the stated primary goal of finding extraterrestrial intelligence, it has proved to the scientific community that distributed computing projects using Internet-connected computers can succeed as a viable analysis tool, and even beat the largest supercomputers. However, it has not been demonstrated that the order of magnitude excess in computers used, many outside the home (the original intent was to use 50,000-100,000 "home" computers), has benefited the project scientifically. (For more on this, see 'threats to project' below.)
Astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
Seth Shostak
Seth Shostak
Seth Shostak is an American astronomer. He grew up in Arlington, VA and earned his physics degree from Princeton University and a Ph.D...
stated in 2004 that he expects to get a conclusive signal and proof of alien contact between 2020 and 2025, based on the Drake equation
Drake equation
The Drake equation is an equation used to estimate the number of detectable extraterrestrial civilizations in the Milky Way galaxy. It is used in the fields of exobiology and the Search for ExtraTerrestrial Intelligence...
. This implies that a prolonged effort may benefit SETI@home, despite its (present) eleven-year run without success in ETI detection.
Technology
Anybody with an at least intermittently Internet-connected computer can participate in SETI@home by running a free program that downloads and analyzes radio telescopeRadio telescope
A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...
data.
Observational Data
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
is recorded on 36 Gigabyte
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...
tapes at the Arecibo Observatory
Arecibo Observatory
The Arecibo Observatory is a radio telescope near the city of Arecibo in Puerto Rico. It is operated by SRI International under cooperative agreement with the National Science Foundation...
in Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
, each holding 15.5 hours of observations, which is then mailed to Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
. Arecibo
Arecibo
Arecibo may refer to:*Arecibo, Puerto Rico, a municipality located by the Atlantic Ocean*Arecibo Observatory, a very sensitive radio telescope located approximately south-southwest from the city of Arecibo...
does not have a high bandwidth
Bandwidth (computing)
In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a measure of available or consumed data communication resources expressed in bits/second or multiples of it .Note that in textbooks on wireless communications, modem data transmission,...
Internet connection, so data must go by postal mail
Mail
Mail, or post, is a system for transporting letters and other tangible objects: written documents, typically enclosed in envelopes, and also small packages are delivered to destinations around the world. Anything sent through the postal system is called mail or post.In principle, a postal service...
to Berkeley at first. Once there, it is divided in both time
Time domain
Time domain is a term used to describe the analysis of mathematical functions, physical signals or time series of economic or environmental data, with respect to time. In the time domain, the signal or function's value is known for all real numbers, for the case of continuous time, or at various...
and frequency domain
Frequency domain
In electronics, control systems engineering, and statistics, frequency domain is a term used to describe the domain for analysis of mathematical functions or signals with respect to frequency, rather than time....
s work units of 107 seconds of data, or approximately 0.35 MB, which overlap in time but not in frequency. These work units then get sent from the SETI@home server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
over the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
to personal computers around the world to analyze.
The analysis software can search for signals with about one-tenth the strength of those sought in previous surveys, because it makes use of a computationally intensive algorithm
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
called coherent integration that no one else has had the computing power to implement.
Data is merged into a database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...
using SETI@home computers in Berkeley. Interference
Interference (communication)
In communications and electronics, especially in telecommunications, interference is anything which alters, modifies, or disrupts a signal as it travels along a channel between a source and a receiver. The term typically refers to the addition of unwanted signals to a useful signal...
is rejected, and various pattern-detection algorithms are applied to search for the most interesting signals.
Software
The SETI@home distributed computing software runs either as a screensaverScreensaver
A screensaver is a type of computer program initially designed to prevent phosphor burn-in on CRT and plasma computer monitors by blanking the screen or filling it with moving images or patterns when the computer is not in use...
or continuously while a user works, making use of processor time that would otherwise be unused.
The initial software platform, now referred to as "SETI@home Classic", ran from May 17, 1999 to December 15, 2005. This program was only capable of running SETI@home; it was replaced by Berkeley Open Infrastructure for Network Computing
Berkeley Open Infrastructure for Network Computing
The Berkeley Open Infrastructure for Network Computing is an open source middleware system for volunteer and grid computing. It was originally developed to support the SETI@home project before it became useful as a platform for other distributed applications in areas as diverse as mathematics,...
(BOINC), which also allows users to contribute to other distributed computing projects at the same time as running SETI@home. The BOINC platform will also allow testing for more types of signals.
The discontinuation of the SETI@home Classic platform has rendered older Macintosh
Macintosh
The Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...
computers running pre-Mac OS X versions of the Mac OS
Mac OS
Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...
unsuitable for participating in the project.
SETI@home is available for the Sony PlayStation3 console.
On May 3, 2006 new work units for a new version of SETI@home called "SETI@home Enhanced" started distribution. Since computers now have the power for more computationally intensive work than when the project began, this new version is more sensitive by a factor of two with respect to Gaussian signals and to some kinds of pulsed signals than the original SETI@home (BOINC) software. This new application has been optimized to the point where it will run faster on some workunits than earlier versions. However, some workunits (the best workunits, scientifically speaking) will take significantly longer.
In addition, some distributions of the SETI@home applications have been optimized for a particular type of CPU. They are referred to as "optimized executables" and have been found to run faster on systems specific for that CPU. , most of these applications are optimized for Intel processors (and their corresponding instruction sets).
The results of the data processing are normally automatically transmitted when the computer is next connected to the Internet; it can also be instructed to connect to the Internet as needed.
Statistics
With over 5.2 million participants worldwide, the project is the distributed computing project with the most participants to date. The original intent of SETI@home was to utilize 50,000-100,000 home computers. Since its launch on May 17, 1999, the project has logged over two million years of aggregate computing time. On September 26, 2001, SETI@home had performed a total of 1021 floating pointFloating point
In computing, floating point describes a method of representing real numbers in a way that can support a wide range of values. Numbers are, in general, represented approximately to a fixed number of significant digits and scaled using an exponent. The base for the scaling is normally 2, 10 or 16...
operations. It is acknowledged by the Guinness World Records
Guinness World Records
Guinness World Records, known until 2000 as The Guinness Book of Records , is a reference book published annually, containing a collection of world records, both human achievements and the extremes of the natural world...
as the largest computation in history. With over 278,832 active computers in the system (2.4 million total) in 234 countries, as of November 14, 2009, SETI@home has the ability to compute over 769 teraFLOPS. For comparison, the K computer
K computer
The K computer – named for the Japanese word , which stands for 10 quadrillion – is a supercomputer being produced by Fujitsu at the RIKEN Advanced Institute for Computational Science campus in Kobe, Japan. In June 2011, TOP500 ranked K the world's fastest supercomputer, with a rating...
, which as of June 20, 2011 was the world's fastest
TOP500
The TOP500 project ranks and details the 500 most powerful known computer systems in the world. The project was started in 1993 and publishes an updated list of the supercomputers twice a year...
supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...
, achieved 8162 teraFLOPS.
Project future
There were future plans to get data from the Parkes ObservatoryParkes Observatory
The Parkes Observatory is a radio telescope observatory, 20 kilometres north of the town of Parkes, New South Wales, Australia. It was one of several radio antennas used to receive live, televised images of the Apollo 11 moon landing on 20 July 1969....
in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
to analyse the southern hemisphere. However, as of March 9, 2009, these plans were not mentioned in the project's website. Other plans include a Multi-Beam Data Recorder, a Near Time Persistency Checker and Astropulse
Astropulse
Astropulse is a distributed computing project that uses volunteers across the globe to lend their unused computing power to search for primordial black holes, pulsars, and ETI. Volunteer resources are harnessed through Berkeley Open Infrastructure for Network Computing platform...
(an application that uses coherent dedispersion to search for pulsed signals). Astropulse will team with the original Seti@Home to detect other sources, such as rapidly rotating pulsars, exploding primordial black holes, or as-yet unknown astrophysical phenomena. Beta testing of the final public release version of Astropulse was completed in July 2008 and the distribution of work units to higher spec machines capable of processing the more CPU intensive work units started in mid July 2008.
Competitive aspect
SETI@home users quickly started to compete with one another in an effort to process the maximum number of work units. Teams were formed to combine the efforts of individual users. The competition continued, and grew larger with the introduction of BOINC.As with any competition, attempts have been made to 'cheat' the system and claim credit for work that has not been performed. To combat cheats, the SETI@Home system sends every workunit to multiple computers, a value known as "initial replication" (currently 2). Credit is only granted for each returned workunit once a minimum number of results have been returned and the results agree, a value known as "minimum quorum" (currently 2). If, due to computation errors or cheating by submitting false data, not enough results agree, more identical workunits are sent out until the minimum quorum can be reached. The final credit granted to all machines which returned the correct result is the same, and is the lowest of the values claimed by each machine. The claimed credit by each machine for an identical workunit often varies due to very minor differences in floating point arithmetic on different processors.
Some users have installed and run SETI@home on computers at their workplaces — an act known as
'Borging', after the assimilation-driven Borg of Star Trek
Star Trek
Star Trek is an American science fiction entertainment franchise created by Gene Roddenberry. The core of Star Trek is its six television series: The Original Series, The Animated Series, The Next Generation, Deep Space Nine, Voyager, and Enterprise...
. In some cases, SETI@home users have misused company resources to gain work-unit results — with at least two individuals getting fired for running SETI@home on an enterprise production system. There is a thread in the newsgroup alt.sci.seti which bears the title "Anyone fired for SETI screensaver" and ran starting as early as September 14, 1999.
Other users collected large quantities of equipment together at home to create "SETI farms", which typically consist of a number of computers consisting of only a motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...
, CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
, RAM
Ram
-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...
and power supply
Power supply
A power supply is a device that supplies electrical energy to one or more electric loads. The term is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy to electrical energy...
that are arranged on shelves as diskless workstations running either Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
or old versions of Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
"headless" (without a monitor).
Threats to the project
Like any project of prolonged duration, there are factors that may result in its termination. Some of these are detailed below:Potential closure of Arecibo Observatory
At present, SETI@home procures its data from the Arecibo ObservatoryArecibo Observatory
The Arecibo Observatory is a radio telescope near the city of Arecibo in Puerto Rico. It is operated by SRI International under cooperative agreement with the National Science Foundation...
facility operated by the National Astronomy and Ionosphere Center and administered by Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...
.
The decreasing operating budget for the observatory has created a shortfall of funds which has not been made up from other sources such as private donors, NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
, other foreign research institutions, nor private non-profit organizations such as SETI@home. The National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
has made it clear that Arecibo will close in 2011 without such funds, and therefore the present data stream for SETI@home would cease in that situation.
However, in the overall longterm views held by many involved with the SETI project, any usable radio telescope could take over from Arecibo, as all the SETI systems are portable and relocatable.
Alternative distributed computing projects
When the project was launched there were few alternative ways of donating computer time to research projects. However, there are now many other projects that are competing for such time.More restrictive computer use policies in businesses
In one documented case, an individual was fired for explicitly importing and using the SETI@home software on computers used for the U.S. state of Ohio. In another incident a school IT director resigned after his installation reportedly cost his school district $1 million in removal costs. Police are investigating the incident.As of October 16, 2005, approximately one third of the processing for the non-BOINC version of the software was performed on work or school based machines. As many of these computers will give reduced privileges to ordinary users, it is possible that much of this has been done by network administrator
Network administrator
A network administrator, network analyst or network engineer is a person responsible for the maintenance of computer hardware and software that comprises a computer network...
s.
To some extent, this may be offset by better connectivity to home machines and increasing performance of home computers.
Funding
There is currently no government fundingFunding
Funding is the act of providing resources, usually in form of money , or other values such as effort or time , for a project, a person, a business or any other private or public institutions...
for SETI research, and private funding is always limited. Berkeley Space Science Lab has found ways of working with small budgets and the project has received donations allowing it to go well beyond its original planned duration, but it still has to compete for limited funds with other SETI projects and other space sciences projects.
In a December 16, 2007 plea for donations, SETI@home stated its present modest state and urged donations for $476,000 needed for continuation into 2008.
Unofficial clients
A number of individuals and companies made unofficial changes to the distributed part of the software to try to produce faster results, but this compromised the integrity of all the results. As a result, the software had to be updated to make it easier to detect such changes, and discover unreliable clients. BOINC will run on unofficial clients; however, clients that return different and therefore incorrect data are not allowed, so corrupting the result database is avoided.BOINC relies on cross-checking to validate data but unreliable clients need to be identified, to avoid situations when two of these report the same invalid data and therefore corrupt the database.
A very popular unofficial client allows users to take advantage special features provided by their processor(s) such as SSE
Streaming SIMD Extensions
In computing, Streaming SIMD Extensions is a SIMD instruction set extension to the x86 architecture, designed by Intel and introduced in 1999 in their Pentium III series processors as a reply to AMD's 3DNow! . SSE contains 70 new instructions, most of which work on single precision floating point...
, SSE2
SSE2
SSE2, Streaming SIMD Extensions 2, is one of the Intel SIMD processor supplementary instruction sets first introduced by Intel with the initial version of the Pentium 4 in 2001. It extends the earlier SSE instruction set, and is intended to fully supplant MMX. Intel extended SSE2 to create SSE3...
, SSE3
SSE3
SSE3, Streaming SIMD Extensions 3, also known by its Intel code name Prescott New Instructions , is the third iteration of the SSE instruction set for the IA-32 architecture. Intel introduced SSE3 in early 2004 with the Prescott revision of their Pentium 4 CPU...
, SSSE3
SSSE3
Supplemental Streaming SIMD Extensions 3 is a SIMD instruction set created by Intel and is the fourth iteration of the SSE technology.- History :...
and SSE4.1
SSE4
SSE4 is a CPU instruction set used in the Intel Core microarchitecture and AMD K10 . It was announced on 27 September 2006 at the Fall 2006 Intel Developer Forum, with vague details in a white paper; more precise details of 47 instructions became available at the Spring 2007 Intel Developer Forum...
to allow for faster processing. The only downside to this is that if the user selects features that their processor(s) do not support, the chances of bad results and crashes rise significantly. Tools are freely available to tell users what features are supported by their processor(s).
Hardware and database failures
Currently SETI@Home is a test bed for further development not only of BOINC but of other hardware and software (database) technology. Under SETI processing loads these experimental technologies can be more bleeding edge than leading edge. SETI databases don't have typical accounting and business data or relational structures. Non-traditional database uses often do incur greater processing overheads and risk of database corruption and outright database failure. Hardware, software and database failures can (and do) cause dips in project participation.The project has had to shut down several times to change over to new databases capable of handing larger datasets. Hardware failure has proven to be a substantial source of project shutdowns—as hardware failure is often coupled with database corruption.
Project news (Oct 28, 2010)
- The machine that was running the main BOINC database has become too unreliable to use. The backup server does not have the capacity to run the project on its own.
- [...]
- Funding for the new servers has come entirely from very generous donations from the SETI@Home community.
See also
- AstropulseAstropulseAstropulse is a distributed computing project that uses volunteers across the globe to lend their unused computing power to search for primordial black holes, pulsars, and ETI. Volunteer resources are harnessed through Berkeley Open Infrastructure for Network Computing platform...
- Distributed.netDistributed.netdistributed.net is a worldwide distributed computing effort that is attempting to solve large scale problems using otherwise idle CPU or GPU time. It is officially recognized as a non-profit organization under U.S...
- Einstein@HomeEinstein@HomeEinstein@Home is a volunteer distributed computing project hosted by the University of Wisconsin–Milwaukee and the Max Planck Institute for Gravitational Physics . The project is directed by Bruce Allen...
- MilkyWay@homeMilkyWay@HomeMilkyWay@home is a volunteer distributed computing project in astrophysics running on the Berkeley Open Infrastructure for Network Computing platform...
- World Community GridWorld Community GridWorld Community Grid is an effort to create the world's largest public computing grid to tackle scientific research projects that benefit humanity...
- Folding@homeFolding@homeFolding@home is a distributed computing project designed to use spare processing power on personal computers to perform simulations of disease-relevant protein folding and other molecular dynamics, and to improve on the methods of doing so...
- Grid computingGrid computingGrid computing is a term referring to the combination of computer resources from multiple administrative domains to reach a common goal. The grid can be thought of as a distributed system with non-interactive workloads that involve a large number of files...
- List of distributed computing projects
- PlanetQuestPlanetQuestPlanetQuest is a grid computing project for discovering new planets and classifying stars from Earth-based observatories' images.-Overview:The PlanetQuest project is currently still under development, and will utilize the BOINC platform.To search for new planets, PlanetQuest developed the Transit...
- PrimegridPrimeGridPrimeGrid is a distributed computing project for searching for prime numbers of world-record size. It makes use of the Berkeley Open Infrastructure for Network Computing platform...
- Rosetta@homeRosetta@homeRosetta@home is a distributed computing project for protein structure prediction on the Berkeley Open Infrastructure for Network Computing platform, run by the Baker laboratory at the University of Washington...
- Systemic (amateur extrasolar planet search project)Systemic (amateur extrasolar planet search project)Systemic is a research project designed to search data for extrasolar planets using amateur astronomers. The project utilizes a downloaded console provided on the Systemic web site allowing users to sort through data sets in search of characteristics which may reveal the presence of a planet within...
- CUDACUDACUDA or Compute Unified Device Architecture is a parallel computing architecture developed by Nvidia. CUDA is the computing engine in Nvidia graphics processing units that is accessible to software developers through variants of industry standard programming languages...
- BrookGPUBrookGPUBrookGPU is the Stanford University graphics group's compiler and runtime implementation of the Brook stream programming language for using modern graphics hardware for non-graphical, general purpose computations...
External links
- The Eerie Silence Expanding the parameters of the search for technological and evolutionary footprints of extrasolar civilizations, beyond only radio signals. (Physics WorldPhysics WorldPhysics World is the membership magazine of the Institute of Physics, one of the largest physical societies in the world. It is an international monthly magazine covering all areas of physics, both pure and applied, and is aimed at physicists in research, industry and education worldwide...
). March 2, 2010.