At the Mercy of the Bugs

The other day we learned about Bee's chigger infestation. Unfortunately, they don't actually feed on blood. They'll just eat her skin. I say unfortunately, because if they were blood sucking insects then she could have got rid of them by getting very drunk on tequilla - after all, remember what it does to those worms.


I'm lucky that I've rarely been bothered by bites. Either I dont' taste good, or my skin just doesn't react so I don't notice. I just get annoyed by moths and terrorised by spiders. Though so far this year, I've not had many eight-legged invaders in my flat.

If Bee survives the chiggers, and West-Nile-Virus-carrying mosquitos, she may or may not be comforted by the thought that some man-made bugs can be more dangerous. I'm referring to bugs in computer programs.

Now, most of these bugs just make your word processor do funny things, and providing you aren't using Windows in your nuclear submarine, the BSOD is unlikely to be a matter of life-or-death. But there are some computer bugs which really have killed.

I was reading about an infamous case of a computer controlled radiation therapy machine which actually fried a few people, zapping them with around 100 times the prescribed dose of radiation. Some of them didn't survive. Of course, the machine also successfully treated a far larger number of patients, and once they found out what was wrong they were able to add some safeguards which solved the problem. The bug in question was a "race condition" - something that depends on the timing of unconnected events, and which is very difficult to find.

That happened in the 80's, and since then engineers have developed a better understanding of the risks of using software in critical systems, such as for flying airplanes or driving cars, and ways to mitigate them.

Debugging the HAL 9000 - with a screwdriver

I'll be away from my blog for a few days, and more importantly that means I won't be commenting on any of yours, but there should be an automatically posted Wordy Wednesday. Bugs notwithstanding. And provided that the software controlling the various transportation I'll be using doesn't crash, I'll be back in about a week...