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This is a project that utilizes the CERN-developed CernVM virtual machine and the BOINC virtualization layer to harness volunteer cloud computing power for full-fledged LHC event physics simulation on volunteer computers.

The theory simulations that have been running as Test4Theory since 2011, were the first of a series of physics applications running on the LHC@home platform. Soon the theory simulations will be followed by more simulations from the LHC experiment collaborations. These applications exploit virtual machine technology, enabling volunteers to contribute to the huge computational task of searching for new fundamental particles and physics at CERN's LHC.

Please visit the LHC@home web site for more documentation, data and instructions. If you have any problem, question or doubt please visit the Message Board, Questions and Answers and FAQ sections of the project.

Join vLHCathome

  • Read our rules and policies
  • Create an account on this page, for this you will need an invitation code. In order to get an invitation code, please check out this post.
  • This project uses BOINC. If you're already running BOINC, select Add Project. If not, download BOINC.
  • When prompted, enter
  • If you're running a command-line version of BOINC, create an account first.
  • If you have any problems, get help here.

User of the day

User profile Profile Pelayo
I'm from Spain and I'm 32. I studied Physics and I work as a Sysadmin for the Spanish Government.


Theory Tasks Available
Theory tasks are available again. The downtime was caused by a suspected NFS related problem that resulted in a bad batch of jobs. The submission code has been hardened to detect this scenario in the future. The maximum jobs in progress limit has been put back to 2 and we will consider increasing this limit in the very near future. 25 Jul 2016, 10:22:11 UTC · Comment

CMS Application Now Available
As the issues with the Theory application will probably not be fixed until after the weekend, the CMS application has been made available for everyone. Due to the slightly larger memory requirements, the the number of tasks that can be run simultaneously on a host has been reduced from 2 to 1. If for whatever reason you do not wish to run the CMS application, you can update your project specific preferences to run only the applications that you select. There will be no more tasks for Theory app until the problem has been resolved. 22 Jul 2016, 20:56:29 UTC · Comment

Theory Application job problems
The Theory Application looks like it is getting a batch of bad input jobs from the MCPlots server. This is causing many task errors.
We are investigating… Please be patient.

We now suggest more people try the CMS Application which has been filled with work for you!
Go to your account page, then click "vLHCathome preferences", then "Edit vLHCathome preferences", then enable the "CMS Simulations" box, then click "Update preferences". Do a project update and you should get CMS tasks.
22 Jul 2016, 13:10:10 UTC · Comment

Authentications Errors
The authentication service is currently down. Tasks will fail with exit status 206 EXIT_INIT_FAILURE until this is resolved. We are working to bring it back up ASAP. 18 Jul 2016, 9:00:02 UTC · Comment

Computation errors
Since we added the 64bit theory application, a number of tasks are failing with Computation Error. This is due to three reasons.

  • The need for Hardware-assisted virtualization for 64bit
  • Additional checks for issues that were not previously detected e.g. idling VMs.
  • A technology change that still requires some hardening for all the issues that we experience when running on random machines around the world.

In the past 24 hours 71.79% of hosts returned a successful task using v2619.31 but 35.38% failed tasks with 7.18% returning both successful and unsuccessful tasks. This suggests that things are working but we still have some improvements to make.

To help the situation, please could everyone periodically (no more than once per day) visit your account page and click on the Task View link in the Computing and credit section to view the results of your tasks. If you do see a computation error, click on the task to see the exit status code and the logging output.

The breakdown of failures by exit code is as follows.

  • 35.14% -1073740791
  • 27.17% 206
  • 18.84% 194
  • 6.16% 207
  • 4.35% 255
  • 3.26% -2135228415
  • 2.54% 1
  • 2.17% 203
  • 2.17% 5
  • 1.45% -186
  • 0.72% 197
  • 0.36% -2147467259
  • 0.36% -185

We will address each one of these in subsequent posts and once we have arrived at a final solution, the issue will either be fixed to stop it occurring or an entry will be added to the FAQ to explain what is going on. 8 Jul 2016, 9:28:55 UTC · Comment

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