Hello,
My brother asked a very good question last night. He is a dyed-in-the-wool advocate of analog guages (keep in mind that he has never owned a computer but that is another matter) - he asked "What happens if the computer fails on a dive?"
My answer to him was "If the computer dies and you are only diving an NDL profile, simply abort the dive, being sure to make your safety stop." He didn't seem to understand the concept that a computer is more accurately determining your nitrogen tissue saturation levels - and regardless of if the values displayed disagree with manual tables - you are still within the NDL.
However, his next question was interesting... he asked "how do you know that it's counting right?" My initial reaction was that it wouldn't start miscounting... but after thinking about it (I am an independant verification and validation manager for software) I began to wonder if there were verification routines coded into the computer. In other words - do the computers use redundant calculations to ensure that the values are correct? Does is check it's own math? Does anyone know?
Also - has anyone even heard of a computer extending out the NDL due to a functional or performance defect? How often do you perform a safety check of the actual vs. real depth displayed? How would one do that - check it at multiple levels, at the begining of the dive or the end of the dive?
I know my aeris atmos II temp sensor is screwy but that doesn't bother me because I am not diving in anything very cold, but it makes me wonder about the other sensors...
My brother asked a very good question last night. He is a dyed-in-the-wool advocate of analog guages (keep in mind that he has never owned a computer but that is another matter) - he asked "What happens if the computer fails on a dive?"
My answer to him was "If the computer dies and you are only diving an NDL profile, simply abort the dive, being sure to make your safety stop." He didn't seem to understand the concept that a computer is more accurately determining your nitrogen tissue saturation levels - and regardless of if the values displayed disagree with manual tables - you are still within the NDL.
However, his next question was interesting... he asked "how do you know that it's counting right?" My initial reaction was that it wouldn't start miscounting... but after thinking about it (I am an independant verification and validation manager for software) I began to wonder if there were verification routines coded into the computer. In other words - do the computers use redundant calculations to ensure that the values are correct? Does is check it's own math? Does anyone know?
Also - has anyone even heard of a computer extending out the NDL due to a functional or performance defect? How often do you perform a safety check of the actual vs. real depth displayed? How would one do that - check it at multiple levels, at the begining of the dive or the end of the dive?
I know my aeris atmos II temp sensor is screwy but that doesn't bother me because I am not diving in anything very cold, but it makes me wonder about the other sensors...