For this, however, that software errors can lead not only to display the legendary blue screen, but also to more serious consequences – counting human lives and billions of dollars – evidence not missing.
Matthew Kocielski, responsible for the safety tests LogicalTrust argues that “errors are everywhere because the software is everywhere, “and lists several examples in which a small omission developers, the desire to save time, or mere inability to foresee all eventualities, led to deplorable consequences.
1. Therac-25
Between 1985 and 1987 6 people was burned as a result of irradiation machine Therac-25. Three of them died as a result of the accident.
In the first case, in which the patient lost as a result of breast and feeling in his hand, it turned out that machine applied the approx. 100 times higher dose of radiation than resulted from the order. The manufacturer, AECL considered, however, that this is not possible, so no action was taken.
Later this the same year – in 1985. – other machine crashed, displaying an error message and take no exposure. The operator, used to moods device, forced execution procedures. The machine was attempting to five times the performance of the exposure, then completely he refused to obey. 3 months later the patient who participated in the procedure, died due to complications of radiation exposure.
AECL very long displacing guilt, recognizing that it is not possible to Therac-25 wrong dose or exposure made despite przeczącego ago Communication. Although it burns has been a few people, and the case went to court. During the proceedings, a spokesman for AECL admitted that he made a “small number” of tests the device was placed on the market.
As it turned out, worth more than $ 1 million machine has been equipped with software written in assembly language, created by one person. Accidents caused two minor omissions programmer. Overall, however, it lacked one, as it turned out, extremely significant line of code. Suddenly dozens of characters.
On the other hand, the error is likely to have been caught before the product on the market, if they do not run more reliable test procedure.
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