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Aubrey Kagan

Unintended Consequences

Aubrey Kagan
michaelmaloney
michaelmaloney
10/31/2018 11:05:16 PM
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Re: Modern electronics is inherently unreliable.
It is interesting to know how different nations practice different safety measures according to their local needs. I guess should a firefighter from another location were to apply to work elsewhere, he/she should be sent for training even after having served for several years. Different rulings call for different understanding and that is important to avoid wrong procedures during an emergency situation.

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cookiejar
cookiejar
2/4/2016 10:27:40 AM
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Modern electronics is inherently unreliable.
The more things that can go wrong, the more things will go wrong - a Murphy law?

Remember the good old days when every large industry had a water tank, high in the sky proudly heralding the company logo?

That was to supply the fire sprinkler system, with gravity providing the pressure and feeding any sprinkler head that opened.  Large diameter pipes were the rule.  Simple, elegant and about as reliable as you can get, but boring to design.

A fire sprinkler system spends most of its lifetime in standby and the expectation that it will work when called for is very high.  A complex diesel powered system can be a reliability nightmare, requiring rigorous routine maintenance and testing.  Diesel or gas fuel doesn't age well.  These days propane or natural gas is the fuel of choice.

I recall the tale of the main NORAD deep underground bunker, responsible for the security of North American during the Cold War.  For their AC backup they had 3 large diesel generators.  Keeping up with the Jones', the military switched to the high cost NiCad batteries as they required less maintenance and were promoted as far more reliable that lead acid batteries used previously.  Once one generator started it could be used to help crank the others.  Then one day there was an actual power failure.   The NiCads surprisingly suffered their now famous "memory effect" having been on trickle charge for months and none of the generators could start.

The solution was to get away from unreliable electrics and electronics.  They installed air compressors and air starters on each engine.  The starting energy was stored in pressurized air tanks.  Cheap, mechanical and proven far more reliable that new-fangled electrics and electronics.

Then there's the rapid obsolescence of active electronic devices.  Flash memories that program everything have only 10 year specified retention.  You can guarantee that nothing electronic designed today will ever be a functioning antique.   Even if you had a fresh flash, how would you get your hands on the listing?  Model T's will outlive our designs by centuries.  All my dozen Heathkits from the 1950s are still fully functioning today.

Most reputable camera manufacturers now only support a new model for 2 years.  After that they destroy their parts inventory. 

How does it feel to be designing throw away junk?

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Rama Murthy
Rama Murthy
2/3/2016 11:37:27 AM
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Newbie
Bang bang thermal runaway of E-M system
I am sure the system would have had some sort of water sensor which would have triggered the Klaxons for no water alert. But the amount of effort to realise a fool proof system is quite high.

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