BOINC stands for Berkeley Open Infrastructure for Network Computing that essentially is a distributed computing tool. It provides middleware functionality and thus is able to work with big data in large distributed systems. This tool is one of the most known tools in Grid computing whereby BOINC was considered as being an information and knowledge Grid. The different geographically distributed nodes in these Grids consist of a large number of heterogenous nodes.
One particular unique property of BOINC Grids is that they implement the concept of using unused resources in a network of distributued computing nodes. This model is called CPU scavenging and the architecture consists of a large number of rather ordinary desktop computers. The idea is to use their free unused computing power during the night or during longer inactive usage periods. CPU scavenging and contributors to such Grids are therefore consided as donors that are in the case of BOINC-based Grids often ordinary citizens. The donation is meant in form of disk space, memory, network bandwidth and some idle CPU cycles otherwise unused on local desktop around the world. Thus this type of computing is also known as volunteer computing because citizens participate on a voluntary basis with a client and can stop sharing CPUs anytime. The BOINC download as a client tool can be found here.
In the last years this computing model has gained momentum and is used in serveral application fields. The most known Grid based on this type of a Grid is the SETI@home project. More details about this project can be found at here. But BOINC as the foundational architecture is also used in Climateprediction.net, Rosetta@home, IBM World Community Grid, and Einstein@Home. All of them contribute to science projects that cure diseases, study global warming, or discover pulsars based on voluntary shared computing power.
More about BOINC Middleware
The following video shows great details about this topic: