The Therac 25 Disaster October 2012 1 Introduction The Therac-25 was a machine for cancer treatment manufactured by the Atomic Energy of Canada Limited (AECL) and went down to history as one of the world’s worst software disasters. The machine was released to the market in 1983 and was later involved in at least 6 accidents that lead to enormous radiation overdoses for the patients. One of the major innovations of the Therac-25 was the move to complete computer control‚ which allowed operators
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The Therac 25 A case study in safety failure • Radiation therapy machine • “The most serious computer-related accidents to date” • People were killed • Reference: Nancy Leveson and Clark Turner‚ “The Investigation of the Therac-25 Accidents”‚ Computer‚ 26‚ 7 (July 1993) pp 18-41. Therac 25 Background • Medical linear accelerator developed by Atomic Energy of Canada‚ Ltd. in mid-1970s • Delivers 25 MeV photons or electrons of various energies • Controlled by PDP-11 minicomputer • Software
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An Investigation of the Therac-25 Accidents -- Part III Nancy Leveson‚ University of Washington Clark S. Turner‚ University of California‚ Irvine Reprinted with permission‚ IEEE Computer‚ Vol. 26‚ No. 7‚ July 1993‚ pp. 18-41. Recall that the Tyler error occurred when the operator made an entry indicating the mode/energy‚ went to the command line‚ then moved the cursor up to change the mode/energy‚ and returned to the command line all within 8 seconds. Since the magnet setting takes about 8 seconds
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CASE STUDY NO.1 THERAC – 25 Aaron James Uy Timosa BSIT – 4 INTRODUCTION The Therac-25 was a radiation therapy machine produced by Atomic Energy of Canada Limited (AECL) after the Therac-6 and Therac-20 units (the earlier units had been produced in partnership with CGR of France). It was involved in at least six accidents between 1985 and 1987‚ in which patients were given massive overdoses of radiation‚ approximately 100 times the intended dose. These accidents highlighted
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Investigation of the Therac-25 AccidentsNancy Leveson‚ University of WashingtonClark S. Turner‚ University of California‚ IrvineReprinted with permission‚ IEEE Computer‚ Vol. 26‚ No. 7‚ July 1993‚ pp. 18-41. Computers are increasingly being introduced into safety-critical systems and‚ as a consequence‚ have been involved in accidents. Some of the most widely cited software-related accidents in safety-critical systems involved a computerized radiation therapy machine called the Therac-25. Between June
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as they launched their new cancer therapy machine‚ Therac-25.The machine according to the chief engineer offered two modes of radiation therapy to cure cancer. This machine according to some was the innovation of the century and a gift to mankind. As the team of engineers was celebrating the day of the launch of their “successful invention”‚ the medical team of the Death Valley Cancer Hospital (DVCH) was installing the first ever model of Therac-25.This was not the only big news why AECL was in the
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Sacred Heart Convent Higher Secondary School Computer File Submitted to: Submitted by: Sanjay Chauhan Mohi Saxena Class – 10th A Roll No. - 8 Acknowledgement I owe a great many thanks to a great many people who helped and supported me during the writing of this project. My deepest thanks to my teacher
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SAC PRESIDENT’S LETTER 25 by 25 is not 625 We‚ doctors‚ nurses‚ cardiology technicians and other professions related with cardiology have hopes and projects for our personal‚ institutional and society lives. Yet‚ we sometimes feel confused when we think about the population. What can we do to improve public health? We can all contribute and work together with our Society. During the past year‚ we have launched the 25 by 25 Program. 25 by 25 is the project of the Argentine Society of Cardiology and
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Malacanang has declared February 25 as a special holiday for all schools nationwide. People Power Day or Araw ng People Power is a school holiday. This is in commemoration of the 1986 People Power Revolution. Senator Gregorio Honasan‚ a former rebel soldier‚ was one of the major figures in the 1986 EDSA Revolution. As the anniversary of the 1986 EDSA revolution approaches‚ he thinks that there is no reason yet to "celebrate" its anniversary. For now‚ the Philippines can only "commemorate it." "Siguro
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ISDN ISDN By Thomas A. Fine‚ (fine@cis.ohio-state.edu) ABSTRACT: Described here are the basics of ISDN‚ including much pracitical information for the consumer‚ as well as some fairly technical descriptions of ISDN‚ and finally some discussion on where ISDN is going in the future. Table of Contents q ISDN Overview r r r r Motivation and History What is IDSN? B-IDSN Fitting things together Access Interfaces Provided The ISDN Reference Configurations Your house’s network (S/T reference
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