A language specification published in 1993 by experts in compiler writing and parallel computation, the aim of which is to define a set of directives which will allow a Fortran 90 program to run efficiently on a distributed memory machine. At the time of writing, many hardware vendors have expressed interests, a few have preliminary compilers, and a few independent compiler producers also have early releases. If successful, HPF would mean data parallel programs can be written portably for various multiprocessor platforms.