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When Bad Software Can Kill
bhoman writes "A wrist computer that tracks and calculates safe diving times and
limits for SCUBA divers had a dangerous software bug that may have been covered
up by company executives.
This SF Chronicle Article
details the problem, product, company, and some of the lawsuits.
According to the Chron article, company execs tried to cover up and
deny the problem for years, but their
official website
makes it look like they did a voluntary recall."
Exposure is a good fictional title about a certain floating-point bug in a mainstream CPU by a popular fictional chip maker. Doesn't matter if the software is perfect if the hardware isn't.
Job? I don't have time to get a job! Who will sit around and bitch about being broke and unemployed then?
Agreed. Personally, (and according to PADI recommendations, I believe,) I don't trust computers at all. I have one, yes, but I still trust the tables a whole lot more. Someone recently showed me the wheel, which is apparently easier to screw up than the tables but far more accurate.
Checks and balances. I use the computer to make sure I'm doing the manual calclations correctly, and the manual calculations to keep the computer honest.
Then again, I'm strictly a recreational diver. Pros and semi-pros are a completely different story.
-- Minds are like parachutes... they work best when open.
I attend a small state university that is decidedly not renowned for its CS program. I'm coming up on my senior year. In no less than three class (Data Structure, Software Engineering, Algorithms) I have spent at least a week concentrating purely on proof of the correctness of an algorithm by various methods. Software Engineering took over a month on testing, primarily concentrating on mathematically rigorous proofs and automated tests (because a mathematically correct and proven algorithm can easily be implemented incorrectly). Pardon my insulting question, but when was the last time you attended college?
You like splinters in your crotch? -Jon Caldara
However, your insulin pump probably has a warning (or the doctor who gave you the instruction on how to use it) that says if you do item A and item B, don't do item C.
As a certified diver (of about a year and a half), I know that they specifically say that you should never go flying less than 12 hours before you take a plane ride (even a small cesna), and, if you do multiple dives you should wait at least 24 hours.
This is not to say that the company was not at fault on this one, but, the divers themselves said that they finished the one dive at 10pm for a flight at 6:30am. I know that the absolute minimum is 4 hours (I did a flying after diving study with DAN), but, this is the limit of the dive tables and should NEVER be approached. All of the major certifying organizations will tell you this.
-CPM
---You're all I need, When the water runs deep, You're all I need, Now I cry my soul to sleep -- Collective Soul, Needs
I don't dive much, but I still have my padi dive table.
h tm l
"For flying up to 8,000 feet after diving: Less then one hour TBT (Total bottom time) , wait 4 hours; less then 4 hours TBT, wait 12 hours." *PADI tive tables (C) 1983
[where TBT = RNT Residual nitrogen time) + Actual Bottom time ]
I dont have my padi manual onhand to estimate how long the folks were down as my table doesn't cover flight, only covers up to 24hours reccomended desaturation time, and doesn't cover this Nitrox stuff.
http://www.stud.ntnu.no/~playboy/diving/diving.
My old PADI book wouldn't cover Nitrox either, so if I were to use it, I would have no choice but to accept their information as fact, or buy new tables.
There is no sanctuary. There is no sanctuary. SHUT UP! There is no shut up. There is no shut up.
No it doesn't. A computer maximises bottom time, by calculating how much nitrogen is going in and out of different ``tissue groups'' in your body, and calculating how saturated those tissue groups are.
When you reach a certain level of saturation, the computer has calculated that if you take any more nitrogen in, you will not be able to outgas it safely in time, if you ascend at a normal speed, hence giving you a decompression stop.
The few computers that do use air consumption in their calculations, only use it to make the model more concervative when your air consumption is going up (ie, a sign of stress).
Make sure you visit this site before ever laying down in that chair. A recent study (Feb. 2003, on the site) indicates between 10 and 20% of refractive surgery patients have complications, a number that is far above what the LASIK industry is touting as its failure rate.
Of particular interest are the stories concerning doctors who have overridden software safeguards and have continued the procedure, resulting in broken blades in the eyes and some other not-so-pleasant outcomes. Not strictly in the "bugs killling people" dept., but it does make you think whether you trust your eyes to a software developer.