Another topic is cluster computing, that is, writing programs that make collective use of a multitude of servers containing GPUs. These are the server farms that populate the data-processing facilities of well-known internet companies such as Facebook and Google, as well as the scientific supercomputing facilities used by governments and militaries. Clusters are generally programmed with a programming paradigm called message-passing interface (MPI), which is an interface used with languages such as C++ or Fortran that allows you to program many computers that are connected to the same network.