An Analysis of Two Formal Methods: VDM and Z

This paper compares and contrasts the strengths and weaknesses of the Vienna Development Method (VDM) and Z in the software design life cycle phase, and compares and contrasts VDM and Z to other formal models. Tool support, lessons learned, and technical and achieved business benefits are emphasized. Based on available data, this paper analyzes the return-on-investment (ROI) from use of these methods, and this ROI data is compared to ROI data from cleanroom software engineering and other process improvement methods.