In the last years PVM became a standard of parallel programming on workstation clusters. Several tools were developed to give the programmer support during all phases of the parallel software life cycle. Relevant phases cover specification and design, implementation (including debugging), maintenance (including performance debugging), and production (uses load balancing and fault tolerance). The next section will give an overview on existing famous PVM tools covering these phases. The reason why they are famous lies mainly in the fact that they are the only ones available. However, some of them are rather advanced and definitely increase the programmers' productivity.