The blacs project is an ongoing investigation whose purpose is to create a linear algebra oriented message passing interface that may be implemented efficiently and uniformly across a large range of distributed memory platforms.
you can choose between an implementation based on mpi or pvm. this package uses pvm.
there are packages for the shared libraries, for the static libraries and the development files (this one) and for test programs.
most users do not need to install this package directly because it is used as a high level driver for the communication in the scalapack packages. therefore, it is installed when installing scalapack. scalapack is a parallel version of lapack and is used on beowulf type clusters.