"Planning and Resource Reasoning" ("PARR") is the name now applied to a scheduling methodology and to computer programs developed to implement the methodology during the years 1985 through 1987. In PARR, one uses heuristics and reactive techniques to build schedules. PARR software is generic enough to be useable in almost any scheduling application in which electronic representations of the resources to be scheduled are available, and in which constraints and conflict-resolution strategies can be represented in terms of heuristics. PARR software takes much less time to produce schedules than do programs that produce optimized schedules. Although PARR-generated schedules are suboptimum, they are acceptable and they satisfy the specified constraints. PARR software can be run in a batch mode for initial generation of schedules, or in an interactive mode for refinement of previously generated schedules.

This work was done by David Richard McLean of Allied Signal for Goddard Space Flight Center. GSC-14097