Executing formal specifications need not be harmful

We review the various arguments which have been advanced for and against the use of executable speciications. Examples are given of the problems which may arise in applying this technique and of the beneets which may accrue. A case study is reported in which execution is used to validate the published speciication of a commercially available package. We conclude that there are circumstances when executable speciications can be of high value but that execution must be used together with, and as a supplement to, other methods of validating speciications such as inspection and proof.