Medical Devices: The Therac-25 (1995)

Re:Medical Devices: The Therac-25 (1995) by userbinator on Monday June 01, 2015 @10:28PM (#9643473)

I see it more generally as the perils of unwarranted complexity. One of the bugs was a race condition that - I'm almost willing to bet - would not have existed if they didn't try to be "overly clever" and incorporate a crude approximation of a multitasking OS in their software.

It is mentioned almost summarily in the report - "Designs should be kept simple" is a phrase in there - but I think that this excessive complexity was one of the biggest factors.

This Hoare quote is relevant: "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies."

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Re:Medical Devices: The Therac-25 (1995) by TickleSteve on Tuesday June 02, 2015 @07:03AM (#9645062)

> "incorporate a crude approximation of a multitasking OS in their software"

Many embedded systems have a 'crude' OS library... and in many cases this makes them far simpler than including an RTOS. Not having seen the code here, I can't comment on this one, but just including a simple scheduler is not necessarily a bad design decision.

The the other aspects of your "Keep It Simple" answer, I fully agree with.

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