Analysis and Improvement of the Variable Binding Scheme in LOGFLOW

The handling of variables is a crucial issue in designing a parallel Prolog system. The so called closed binding environment is an excellent candidate for a binding scheme in a distributed system, however, it has several weaknesses when the computation is not migrating. In this paper the closed binding method is analysed, a possible modification is introduced and the implementation and performance measurement of the hybrid binding scheme in LOGFLOW is described. Keywords: distributed Prolog implementation, binding schemes, closed binding environment, performance evaluation 1 Introduction The central question at implementing an OR-parallel Prolog system is how the multiple bindings can be handled consistently in such a way that the resulting binding scheme accomplishes most of these issues: variable access is in constant time, task switching is in constant time, task creation is in constant time. In [GuJa90] it was shown that all the three conditions can not be satisfied. Additionally..