Multiple Science Applications

Quite simply, a Project may have Multiple Science Applications. The BOINC Client Software will manage them in accordance with the needs of the Project or Projects. The BOINC Client Software supports many different BOINC Powered Projects through the use of the Science Application concept.

Some Projects have different classes of Work Units in that case there will be multiple Science Applications for that Project. In this situation the different Science Applications run at different times depending on what Work Unit is assigned to a Participant's Host. For Example Predictor@Home uses the Science Applications mfold and charmm for different types of Work Units.
Other Projects use Compound Applications. In this case there will be more than one Science Application running at the same time on a Participant's Host. One will normally be the controller and call other Science Applications as needed. Climateprediction.net uses this approach.
When a Project updates their Science Application there is likely to be a period of time when both the old and new Version are on the Host at the same time. This happens because a Work Unit normally must be processed with the same Version of the Science Application as it was created or downloaded with.