The Therac-25 Incident


The objective is this class is to examine, in some detail, a classic computer software related failure. As a case study in the problems that can possibly emanate from software deficiencies, and the strong resistance of the developers to properly investigate the failures brings into clear focus the shortcomings of undisciplined software development.

Class Notes

Examination Questions

References and Readings

Leveson, Nancy, and Clark S. Turner. July 1993. "An Investigation of the Therac-25 Accidents", IEEE Computer, Vol. 25, No. 7, pp. 18-41.

Joyce, E. J. Oct. 1986. "Malfunction 54: Unraveling Deadly Medical Mystery of Computerized Accelerator Gone Awry", American Medical News, pp. 1,13-17.

The initial work of analyzing the Therac-25 incidents was the responsibility of a small Candian company named DLSF. A brief description of their involvement is available.

Last updated 97/01/24
J.A.N. Lee, 1995, 1997.