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We present a fast parallel SAT{solver on a message based MIMD machine. The input formula is dynamically divided into disjoint subformulas. Small subformulas are solved by a fast sequential SAT{solver running on every processor, which is based on the Davis{Putnam procedure with a special heuristic for variable selection. The algorithm uses optimized data structures to modify boolean formulas. Additionally e cient workload balancing algorithms are used, to achieve a uniform distribution of workload among the processors. We consider the communication network topologies d{dimensional processor grid and linear processor array. Tests with up to 256 processors have shown very good e ciency{values (> 0:95).

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