In the past, researchers have conducted experiments linking workstations that provide on the order of 1 to 10 MIPS. Such experiments have included remote execution, computer farms, and migration of computations.
More recently, experiments have focused on linking higher-performance workstations (those providing on the order of 10 to 100 MFLOPS) together with multiprocessors and conventional supercomputers.
To fully exploit these multiple computer configurations, researchers have developed various software packages that enable scientists to write truly heterogeneous programs. Examples of such software packages include Express, P4, Linda, and PVM. Each package is layered over the native operating systems, exploits distributed concurrent processing, and is flexible and general-purpose; all exhibit comparable performance. Their differences lie in their programming model, their implementation schemes, and their efficiency.