15. Read the case of Therac-25 [LEV 93], a medical device that has caused the death of several patients, and:

    1. a) Identify the clauses in the code that were infringed.

    2. b) What could you have said to a representative of AECL who has made the usual

       excuses in the software industry in order to avoid responsibility (complexity, testa- bility, and development process)? To back up your answer, explain in concrete terms what the company could have done to reduce the risks inherent in these three char- acteristics of the software product?

    3. c) You were recently named director of SQA for the new Therac-30 project. This project will reuse Therac-25 technology to produce a more efficient version. What SQA precautions should be taken?

    4. d) You talked with the Software Quality Director for the Therac-25. He shared the lessons learned from the incidents caused by Therac-25. List four of these lessons.