Editing SETI@home (section)

==Technology==
Anybody with an at least intermittently Internet-connected computer was able to participate in SETI@home by running a free program that downloaded and analyzed [[radio telescope]] data.

Observational data were recorded on 2-[[terabyte]] [[SATA]] hard disk drives fed from the [[Arecibo Telescope]] in Puerto Rico, each holding about 2.5 days of observations, which were then sent to [[University of California, Berkeley|Berkeley]].<ref name="Korpela">{{cite journal | title = SETI@home&nbsp;– Massively Distributed Computing for SETI | first = Eric | last = Korpela | author2 = Dan Werthimer | author3 = David Anderson | author4 = Jeff Cobb | author5 = Matt Lebofsky | journal = Computing in Science & Engineering | date = January 2001 | pages = 78–83 | url = http://setiathome.ssl.berkeley.edu/~korpela/papers/CISE.pdf | doi = 10.1109/5992.895191 | volume = 3 | issue = 1 | bibcode = 2001CSE.....3a..78K | access-date = October 25, 2005 | archive-date = October 23, 2014 | archive-url = https://web.archive.org/web/20141023225217/http://setiathome.ssl.berkeley.edu/~korpela/papers/CISE.pdf }}</ref> Arecibo does not have a broadband [[Internet access|Internet connection]], so data must go by [[postal mail]] to Berkeley.<ref>{{cite web |url=http://seticlassic.ssl.berkeley.edu/about_seti/about_seti_at_home_2.html |title=About SETI@home page 2 |publisher=Seticlassic.ssl.berkeley.edu |access-date=17 May 2009 |archive-date=March 10, 2020 |archive-url=https://web.archive.org/web/20200310022312/http://seticlassic.ssl.berkeley.edu/about_seti/about_seti_at_home_2.html |url-status=live }}</ref> Once there, it is divided in both [[time domain|time]] and [[frequency domain]]s ''work units'' of 107 seconds of data,<ref>{{cite web | title = The SETI@home Sky Survey | url = http://seticlassic.ssl.berkeley.edu/sciencepaper.html | author = SETI@home | date = 2001<!-- no valid last modified available --> | access-date = 2 June 2006 | archive-date = April 22, 2020 | archive-url = https://web.archive.org/web/20200422000741/http://seticlassic.ssl.berkeley.edu/sciencepaper.html | url-status = live }}</ref> or approximately 0.35 [[megabytes]] (350 [[kilobytes]] or 350,000 [[bytes]]), which overlap in time but not in frequency.<ref name="Korpela"/> These work units are then sent from the SETI@home [[Server (computing)|server]] over the Internet to personal computers around the world to analyze.

Data was merged into a [[database]] using SETI@home computers in Berkeley. [[Interference (communication)|Interference]] was rejected, and various pattern-detection algorithms were applied to search for the most interesting signals.

The project used [[CUDA]] for [[GPU]] processing starting in 2015.<ref>{{Cite web|url=https://setiathome.berkeley.edu/apps.php|title=Applications|access-date=July 5, 2019|archive-date=October 5, 2022|archive-url=https://web.archive.org/web/20221005061217/https://setiathome.berkeley.edu/apps.php|url-status=live}}</ref>

In 2016 SETI@home began processing data from the [[Breakthrough Listen]] project.<ref>{{Cite web|url=https://breakthroughinitiatives.org/news/3|title=Breakthrough Initiatives|website=breakthroughinitiatives.org|access-date=31 May 2019|archive-date=May 31, 2019|archive-url=https://web.archive.org/web/20190531153829/https://breakthroughinitiatives.org/news/3|url-status=live}}</ref>

===Software===
[[File:BOINC Manager Screenshot.jpg|thumb|left|upright|The [[Berkeley Open Infrastructure for Network Computing|BOINC]] Manager working on the SETI@home project (v 7.6.22)]]
[[Image:Setiathomeversion3point07.JPG|thumb|right|Screenshot of SETI@home Classic Screensaver (v3.07)]]
<!--Generally needs to go much deeper about how the software works internally rather than how it appears to a non-technical participant. Maybe put this in how it section and make this a history section?-->

The SETI@home volunteer computing software ran either as a [[screensaver]] or continuously while a user worked, 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 volunteer computing projects at the same time as running SETI@home. The BOINC platform also allowed testing for more types of signals.

The discontinuation of the SETI@home Classic platform rendered older [[Mac (computer)|Macintosh]] computers running the [[classic Mac OS]] (pre December, 2001) unsuitable for participating in the project.

SETI@home was available for the Sony [[PlayStation 3]] console.<ref>{{cite web|url=http://www.dotsch.de/boinc/SETI@home%20applications.html|archive-url=https://web.archive.org/web/20080108193313/http://www.dotsch.de/boinc/SETI%40home%20applications.html|archive-date=2008-01-08|title=SETI@home applications}}</ref>

On May 3, 2006, new work units for a new version of SETI@home called "SETI@home Enhanced" started distribution. Since computers had the power for more computationally intensive work than when the project began, this new version was more sensitive by a factor of two concerning Gaussian signals and to some kinds of pulsed signals than the original SETI@home (BOINC) software. This new application had been optimized to the point where it would run faster on some work units than earlier versions. However, some work units (the best work units, scientifically speaking) would take significantly longer.

In addition, some distributions of the SETI@home applications were optimized for a particular type of [[CPU]]. They were referred to as "optimized executables", and had been found to run faster on systems specific for that CPU. {{As of|2007}}, most of these applications were optimized for [[Intel]] processors and their corresponding [[instruction set]]s.<ref>{{cite web |url=http://lunatics.kwsn.net |title=Seti@Home optimized science apps and information |publisher=Lunatics.kwsn.net |access-date=17 May 2009 |archive-url=https://web.archive.org/web/20090424210331/http://lunatics.kwsn.net/ |archive-date=April 24, 2009 }}</ref>

The results of the data processing were normally automatically transmitted when the computer was next connected to the Internet; it could also be instructed to connect to the Internet as needed.