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On 12 Apr 2002 at 15:41, dickbo wrote: > I would submit to you the idea that there is no such thing as an > intermittent "Design" problem in that the fault will not be found in the > design but somewhere else such as a single or machine batch component fault > or even a test procedure shortcoming. > > Of course it might just be a user failing, but God forbid the paying > customer could ever be at fault. As an engineer (25+ years) I have seen my share of products/ designs used in ways that I'd not planned for, or clearly in violation of suggested operating procedures or parameters. Notwithstanding, what you say just isn't so. Either that, or you're just playing with semantics. Testing is done (in part) to find and root out engineering problems. If it fails to do that, is it a failure of the testing? Maybe. But it is still an engineering problem, at the root. Products fail in myriad ways. Sometimes components fail, sometimes the design's at fault. Sometimes it's a combination of the two: the design pushes a component into an area of operation for which it was not properly tested or qualified for use. Perhaps the resistor was dissipating more power than it was rated for. Perhaps the ESR rating of the capacitor wasn't properly observed. Perhaps the component (whatever it is) is being used in a way that it's creators/designers never anticipated. The possibilities (for error) are endless. Firmware fails for exactly the same reasons: some combination of factors pushes the code into a region that was never properly tested. For some users, the code doesn't fail. For others, it does. Testing may or may not reveal the flaw. If you were correct, Dickbo, there'd be no need for the Consumer Products Safety Commission, or the thousands of recalls of consumer products in the USA, each year. I'm not sure what you're implying here, about the specific issue. Are you suggesting that Lawrence Smith, and I, and others, have somehow brought on the banding problem through our own misuse of the product? Are you suggesting that the space shuttle "Challenger" was brought down through anything other than an intermittent design problem? Or would you prefer to call that a failure of testing? Either way, I say it as a classic (and tragic) engineering problem -- exacerbated, as usual, by economics and politics. rafe b. - Turn off HTML mail features. Keep quoted material short. Use accurate subject lines. http://www.leben.com/lists for list instructions.