Editing World Community Grid (section)

==Operation==
[[File:BOINC in system tray.png|frame|The World Community Grid client software works in the background, showing itself as a small icon in the computer's [[system tray]]. When the [[BOINC]] client is used, as in this example, the icon is yellow and blue.]]
[[File:WCG on BOINC.png|thumb|250px|The client software's status window, displaying information about the work currently being done in the background. This particular computer is 95.6% complete with its current workunit. When it reaches 100%, it will start on a new workunit and the results of the previous workunit will be transmitted back to WCG.]]
The World Community Grid software uses the unused computing time of [[Internet]]-connected devices to perform research calculations.<ref name="Weiss">{{cite news |url=http://www.computerworld.com/hardwaretopics/hardware/gridcomputing/story/0,10801,97577,00.html |title='World Community Grid' seeks to harness unused computers |vauthors=Weiss T |publisher=[[Computerworld]] |date=2004-11-17 |access-date=2007-07-28 |archive-date=2007-08-15 |archive-url=https://web.archive.org/web/20070815122553/http://www.computerworld.com/hardwaretopics/hardware/gridcomputing/story/0,10801,97577,00.html |url-status=live }}</ref> Users install WCG client software onto their devices. This software works in the background, using spare system resources to process work for WCG.<ref name="Weiss"/><ref name="Privacy Policy">{{cite web |url=http://www.worldcommunitygrid.org/viewMemberPolicy.do |title=Member Policy |work=Privacy and Security |publisher=World Community Grid |access-date=2007-07-28 |archive-date=2007-08-10 |archive-url=https://web.archive.org/web/20070810071318/http://www.worldcommunitygrid.org/viewMemberPolicy.do |url-status=live }}</ref> When a piece of work or ''workunit'' is completed, the client software sends it back to WCG over the Internet and downloads a new workunit.<ref name="About Us"/><ref>{{cite web |url=http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=results#29 |title=Returning Results: What is a Work Unit? |work=Help |publisher=World Community Grid |access-date=2007-08-05 |archive-date=2007-07-14 |archive-url=https://web.archive.org/web/20070714073132/http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=results#29 |url-status=live }}</ref> To ensure accuracy, the WCG servers send out multiple copies of each workunit.<ref>{{cite web |url=http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=install#62 |title=Installing the Windows Agent: If I re-install the software, will the work that I am doing be lost forever? |work=Help |publisher=World Community Grid |access-date=2007-08-05 |archive-date=2007-07-14 |archive-url=https://web.archive.org/web/20070714074133/http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=install#62 |url-status=live }}</ref> Then, when the results are received, they are collected and validated against each other.<ref>{{cite web |url=http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=points#174 |title=Points: What is validation? |work=Help |publisher=World Community Grid |access-date=2007-07-28 |archive-date=2007-08-10 |archive-url=https://web.archive.org/web/20070810070758/http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=points#174 |url-status=live }}</ref>

World Community Grid offers multiple humanitarian projects under a single umbrella.
Users are included in a subset of projects by default, but may opt out of projects as they choose.<ref>{{cite web
|url=http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=start#203
|title=Getting Started: I'm using the BOINC agent, how do I choose which project my computer processes work for?
|work=Help
|publisher=World Community Grid
|access-date=2014-09-26
|archive-date=2015-02-19
|archive-url=https://web.archive.org/web/20150219202156/http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=start#203
|url-status=live
}}</ref>

Even though WCG makes use of open source client software, the actual applications that perform the scientific calculations may not be. However, several of the science applications are available under a free license, although the source is not available directly from WCG.<ref>{{cite web
|url=http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=wcgagent#215
|title=Agent: I have a platform that isn't supported by World Community Grid. Could I receive the code and compile it myself?
|work=Help
|publisher=World Community Grid
|access-date=2007-08-05
|archive-date=2007-07-14
|archive-url=https://web.archive.org/web/20070714073307/http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=wcgagent#215
|url-status=live
}}</ref>

===Potential problems===
[[File:BOINC running-Task mgr CPU usage history demo-en-1.png|right|thumb|250px|The picture shows particular two CPU usage history (under [[Hyper-threading]]) when [[BOINC]] client software is processing two tasks on each CPU under [[Microsoft Windows]] XP SP2. CPU usage history indicates almost 0% to 100% swing with peak to peak of 3 seconds [[Interval (time)|interval]], when view +update speed set to high, at first half recording period. The rest of half period of history is set to update speed normal, and upper CPU usage history indicates slightly more than 60% and lower CPU usage history show 35% approx. in average.]]
The World Community Grid software increases [[CPU]] usage by consuming unused processing time; in the late 1990s and early 2000s, such calculations were meant to reduce "wasted" CPU cycles.<ref>{{Cite web | url=http://www.sharewarejunkies.com/9zwd11/setihome.htm | title=SETI@Home | access-date=2017-07-28 | archive-date=2019-03-03 | archive-url=https://web.archive.org/web/20190303222604/http://www.sharewarejunkies.com/9zwd11/setihome.htm | url-status=live }}</ref> With modern CPUs, where [[dynamic frequency scaling]] is prevalent, increased usage makes the processor run at higher frequency,<ref>Although on [[Linux]] systems the [https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt CPUfreq frequency scaling governor can be configured otherwise] {{Webarchive|url=https://web.archive.org/web/20170607174541/https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt |date=2017-06-07 }} with the parameter ignore_nice_load.</ref> increasing power usage and heating counter to [[power management]]. Additionally, because of an increasing focus on power performance,<ref>{{Cite web | url=https://www.cpubenchmark.net/power_performance.html | title=PassMark CPU TDP Chart - Performance / Power of available CPUs | access-date=2017-07-28 | archive-date=2017-07-29 | archive-url=https://web.archive.org/web/20170729022431/https://www.cpubenchmark.net/power_performance.html | url-status=live }}</ref> or [[performance per watt]], connecting old/inefficient computers to the grid will increase the total/average power required to complete the same calculations.

The [[BOINC]] client avoids slowing the computer by using a variety of limits that suspend computation when there are insufficient free resources. Unlike other BOINC projects, World Community Grid set the BOINC defaults conservatively, making the chances of computer damage extremely small. The default CPU throttle is 60%. The throttle is coarse-grained; for example, if usage is set to 60% it will work at 100% for 3 seconds, then at 0% for 2 seconds, resulting in an average decrease of processor use.<ref>{{cite web
|url=http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=cpuuse#33
|title=CPU Usage: Why does my PC show high CPU use?
|work=Help
|publisher=World Community Grid
|access-date=2007-08-05
|archive-date=2007-07-14
|archive-url=https://web.archive.org/web/20070714084446/http://www.worldcommunitygrid.org/help/viewTopic.do?shortName=cpuuse#33
|url-status=live
}}</ref>

An add-on program for Windows computers – [http://efmer.eu/boinc/ TThrottle] – can solve the problem of overheating by directly limiting the BOINC project's use of the host computer. It does this by measuring the CPU and/or the GPU temperature and adjusts the run time accordingly. It also uses a shorter switching time of less than one second, resulting in less temperature change during switching.{{citation needed|date=May 2017}}