What makes a bunch of computers on a network to become a computational cluster:
For example, OpenMosix. SSI is smart system software that spreads operating system functions across systems and involves modifications of the Linux kernel.
Queue scheduling system (for example, LSF, Condor, PBS and Grid Engine )
Examples of computational software utilizing MPI:FLUENT (Fluid Dynamics and Heat transfer)
GASP (Gas Dynamics)
AMBER (Molecular dynamics)
NAMD (Molecular dynamics)
GROMACS (Molecular dynamics)