The Ppm Environment Manager

An environment is a set of name-value bindings, maintained for a particular user, tha t are provided to a process at runtime. This can provide a great deal of flexibility in tai loring the behavior of programs to a particular user's preferences. It can also serve as a simple me ans of interprocess communication. To be useful, however, the environment must take into ac count the natural structure of a user's work. Groups of cooperating processes form jobs and sho uld share certain bindings. At the same time. processes in different jobs running on the same machine should share other bindings. A Oat name space for bindings does not provide sufficien t structure to handle these overlapping sets of shared bindings. The PPM Environment Manager p rovides an environment with a variety of contexts, allowing bindings to be, for example, machinespecific or application-specific. The environment, however, remains simple to use. The PPM En vironment Manager was designed to support multiprocess programs, distributed programs, and programs offloaded in a network of machines. A prototype has been implemented on top of UNIX 4.3BSD.