Read Medical Devices: The Therac-25 by Leveson (which is an updated version of An Investigation of the Therac-25 Accidents by Leveson and Turner) and the NYTimes article on recent similar problems.

Although there are many cases in which software design and failure has led to the loss of life, the case of the Therac-25 is among the best known and most widely cited because of the depth of analysis that was performed by professor Nancy Leveson and her graduate student Clark Turner. The Leveson paper is quite long, and not all parts are equally important. This is a good opportunity for you to begin practicing how to get the interesting stuff out of a paper without getting bogged down in minor detail:

• Start with a quick pass, just reading the section headings and the figure captions, to get an idea of the layout of the paper and what kinds of things the authors seem to be trying to communicate.
• Next, skim it quickly, looking primarily at the first and last paragraph of each section.

Now ask yourself why it was assigned as a 6.033 reading, and with that in mind, start working your way through the meat of the paper. Some sections can be skimmed quickly, while other parts require careful study. Not surprisingly, there is also some redundant information that you can ignore.

As you read the paper, try to distinguish solid technical facts from higher-level statements that the authors are trying to make about process, procedures and policy. You might find it useful to note the places where you agree or disagree with the authors' analysis.

Finally, don't be dismayed by unfamiliar technical jargon; make a guess about what it means and move on. The authors may explain it two paragraphs later, or two pages later, or perhaps never get around to it. There is a good chance that you will discover that it didn't actually matter. But if it does, you have something to ask about in recitation.

Before you come to recitation on Thursday, write up (on paper) an answer to the following question:

Name three quality control procedures that might have made a difference, as demonstrated in the examples.