"Sequential Applications - These applications run on a single core. While they may not be parallel (use multiple cores) the end user may run many copies of the same program with different input parameters. This type of computing is often called parametric processing. These types of programs can be written in any type of computer language.
"Threaded Applications - These applications use multiple cores, but only on one SMP node. Most of these programs are written using C/C++ or Fortran and use pthreads or OpenMP - As core counts increase many HPC users are taking advantage of this approach.
"Parallel Applications - These applications are written to use multiple cores across many nodes. They are mostly written in Fortran or C/C++ and use MPI as way to send messages between nodes."
