Apache Incubator project that describes itself as:
Hama is a distributed computing framework based on BSP (Bulk Synchronous Parallel) computing techniques for massive scientific computations.
A little better explanation appears on the Hama blog when answering the question: “How will Hama BSP different from Pregel?:”
Hama BSP is a computing engine, based on BSP model, like a Pregel, and it’ll be compatible with existing HDFS cluster, or any FileSystem and Database in the future. However, we believe that the BSP computing model is not limited to a problems of graph; it can be used for widely distributed software such as Map/Reduce. In addition to a field of graph, there are many other algorithms, which have similar problems with graph processing using Map/Reduce. Actually, the BSP model has been researched for many years in the field of matrix computation, too. http://blogs.apache.org/hama/
Wikipedia has a short article on Bulk synchronous parallel (BSP) computing techniques with some references.