HYPERSEQUENTIAL PROGRAMMING - A NEW WAY TO DEVELOP CONCURRENT PROGRAMS

The authors present hypersequential programming, a new method that eas es the difficulty of concurrent programming and makes the concurrent p rogram highly reliable. The difficulty of concurrent programming is du e mainly to its nondeterminism. The authors classify nondeterminism in to three types: intended, harmful, and persistant. In traditional conc urrent programming, a programmer first designs and implements programs so as to maximize concurrency, which may include all three types of n ondeterminism. She then tries to detect harmful nondeterministic behav ior by testing and debugging them. However, removing all harmful nonde terministic behavior is actually very difficult. Hypersequential progr amming, on the other hand, first serializes the concurrent program to remove all types of nondeterminism, and then the programmer tests and debugs it as a sequential program. Finally, it is parallelized by rest oring only intended and persistent nondeterminism. Hypersequential pro gramming can develop a highly reliable concurrent program, because the injection of harmful nondeterminism is precluded. In this article, th e authors also present a simple embodiment of hypersequential programm ing using Petri nets.