The method for obtaining the signatures of sequences of state codes derived by polynomial division by a given polynomial proposed in this paper ensures identical signatures before each join node of a control flow graph. A set of examples has been successfully encoded, and the method has been proven easy to apply for well-structured controllers. The tool has been written in Prolog. No speed degradation is associated with the proposed scheme.

The paper accomplishes its basic purpose. Its length is appropriate for its subject. The practical approach to online testing of control flow graphs is the best feature of the paper. The solution of the optimization problem could be described more formally. The results are applicable to the implementation of concurrently checked controllers on VLSI. The paper will be useful to designers of VLSI controllers for highly dependable applications, such as transaction systems, railway interlocking systems, avionics computer control systems, medical systems, nuclear plants, and spaceship computers. The references are up to date and the material is presented in a good form.