OR parallel execution of Prolog programs with side effects

With the growing availability of multiprocessors, a great deal of attention has been given to executing Prolog in parallel. A question that naturally arises is how to execute standard sequential Prolog programs with side effects in parallel. The problem of performing side effects in AND parallel systems has been considered elsewhere. This paper presents a method that generates sequential semantics of side effect predicates in an OR parallel system. First, a general method is given for performing data side effects such as read and write. This method is then extended to control side effects such as asserta, assertz, and retract. Finally, a constant-time algorithm for performing cut is presented.