A polynomial-time approximation scheme (PTAS) is derived for the partitioned EDF scheduling of implicit-deadline sporadic task systems upon unrelated multiprocessor platforms that are comprised of a constant number of distinct types of processors. This generalizes earlier results showing the existence of polynomialtime approximation schemes for the partitioned EDF scheduling of implicit-deadline sporadic task systems on (1) identical multiprocessor platforms, and (2) unrelated multiprocessor platforms containing a constant number of processors
