1 / 5

COMP60611: Fundamentals of Parallel and Distributed Systems Direct Reading 1 – Therac-25

Dimitrios Christias Robert Lyon Andreas Petrou. COMP60611: Fundamentals of Parallel and Distributed Systems Direct Reading 1 – Therac-25. Therac-25 is a computer-controlled radiation therapy machine that was designed by Atomic Energy of Canada Limited (AECL).

cesarg
Télécharger la présentation

COMP60611: Fundamentals of Parallel and Distributed Systems Direct Reading 1 – Therac-25

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dimitrios Christias Robert Lyon Andreas Petrou COMP60611: Fundamentals of Parallel and Distributed SystemsDirect Reading 1 – Therac-25

  2. Therac-25 is a computer-controlled radiation therapy machine that was designed by Atomic Energy of Canada Limited (AECL). • It was used in medical institutions to destroy tumors. • Operates in a dual-mode. • Depends more on software routines to ensure safety. • Evolution of Software • Several accidents of radiation overdose happened between 1985 and 1987 using the Therac-25 due to software issues. Introduction Therac-6 Therac-20 Therac-25

  3. Concurrency problems - Therac-25 has a software system that allows concurrent access to shared memory. - The fundamental design of the system was flawed, as it lacked synchronization • Lack of safety - Therac-25 relied only on its software to ensure safety measures and handling errors • Lack of documentation - The system has been developed to display cryptic error messages - The user manuals did not indicate the danger of those malfunctions for the patient health. • Lack of testing - Limited and poor test coverage • The user centred design - User centred design concerns seemed to override patient safety • The role of Government - No information of the development, management and quality control procedures is available • Ignorance of the incidents - system users were unconcerned about the fact that Therac-25 was causing harm through its use Causes of accidents

  4. Adhere to basic principles of software engineering • Proper testing • Extensive documentation • Re-using code • Arrogance in the assumption that the software is safe • Unrealistic risk assessment • Interface design that focused on usability rather than safety conclusion

  5. Bozdag, E., 2009. Therac-25 and the security of the computer controlled equipment. [online], Ethics of Science and Technology. Available at <http://citeseerx.ist.psu.edu> [Accessed 01 October 2011]. • Leveson, N., 1995. Medical Devices: The Therac-25. [online], University of Washington. Available at <http://sunnyday.mit.edu/papers/therac.pdf> [Accessed 01 October 2011]. • Lim, J., 1998. An Engineering Disaster: Therac-25. [online], Available at <http://www.bowdoin.edu> [Accessed 01 October 2011]. references

More Related