NAMD is a parallel molecular dynammic program based on Charm++ parallel objects. Charm++ is a rutime library to let C++ objects communicate with each other efficiently through an asynchronous message driven paradigm. NAMD features IMD(interactive Molecular Dynamics) and SMD(Steered Molecular Dynamics).

References:

http://www.ks.uiuc.edu/Research/namd/2.9/notes.html