Henrik Fransson: When software kills

Bugs may just be a minor nuisance or give you less stars in an app store, but what if they harm or even kill people?
In the 1980s, the computer-controlled Therac-25 radiotherapy linear accelerator malfunctioned and caused severe injury or death to six patients. Two bugs have historically been attributed to what happened, but does this mean all blame is on the developer? What risks do we face when putting too much trust in software? And what has been done to prevent future accidents?
The event was kindly hosted by Atlas Copco, www.atlascopco...
"The Mine" is an awesome location, but there was a notable echo in the audio. I've cleaned it up as best as I could. Hope you enjoy the video!
The Meetup event page:
www.meetup.com...
More information about C++ Usergroups in Sweden at swedencpp.se

[@weekendwarrior3420]

The hospital had better people than the manufacturer.

[@StefanoBorini]

main issues of SOUP and also other requirements from IEC62304: 1) SOUP validation procedures, especially if the SOUP is required to be validated for class C, are not strictly prescribed. In other words, if memory serves me correctly, the IEC standard says nothing about how you are supposed to perform validation activities on the SOUP. Do you test only the functions you use, or the whole package, and if the latter, how? Imagine you use numpy to perform matrix multiplications. What do you do to ensure that numpy is fit for purpose in your class C application? 2) I personally found myself unable to verify if currently open bugs on third party software were affecting us, because the vendor (Note: not an opensource vendor. A microcontroller, closed source vendor) refused to release information about currently open defects of their software and hardware. The consequence is that you are asked, as for IEC62304, unable to verify which standing issues in your third party products may affect your product. Eventually I managed to get them to release this information only to us, but it took *a lot* of effort.

[@weekendwarrior3420]

PDP-11 is 16-bit. int would be 16 bits there.

[@hmf4711]

Correct, the PDP-11 is 16 bit, but some CPU registers could also be used as 8 bit registers. I guess that's what they did, since the reports state that overflow happened every 256:th call.