I've followed this thread and the last similar one with interest, being a techie type and all. There's a couple points I'd like to express here from the viewpoint of a knowledgable diver.
!) When Uwatec's computer factored offgassing during the surface interval as though you were still on nitrox (if you had dived on nitrox), We called that a Bug because it was an error in design that hurt people. (Fatal Exception should have been more like it)
2) The Cobra and Vyper, under certain very possible conditions, will, because of programming design, "tox you out" on profiles that by any other reasonable way of measurement, should not put you over 25% or so. Karl has displayed evidence that convinces me of this, and I'm a skeptic.
3) The Cobra and Vyper do this, With Out warning you. Karl has displayed evidence that convinces me of this also, and I'm a big skeptic.
4) The Vyper and to a lesser extent, the Cobra, are marketed to a generally lesser sophisticted and more likely to "blindly follow the computer than have the dive knowledge to know when it's flukey" segment of divers than the Vytec.
5) It doesn't take a genius to see where some one seeing his computer toxing him out is gonna do a WAPA (Wild And Paniced Ascent) sooner or later. Especially, since they never got any alarm indication that the cns clock was in 10X overdrive.
6) Based on the above liklihood for injury, the fact that the Vyper and Cobra initiate the cns clock overdrive function and the alarm function in what can only be considered to be, reverse order, makes that design issue a BUG, and should therefore be addressed. I can't imagine anyone having their car come to a screeching smoking halt, and THEN the light comes on the dash and says, "Low Oil" "Check Engine". I'm gonna guess everyone would expect the warning light first.
7) The fact that the computers can ERRANTLY tox you out, can render them Useless for repetitive diving, or even some possible multilevel profiles. Since those two reasons are what most divers buy computers for, and the computers can not be counted on to perform under All Reasonable situations, Then that's a BUG, and should be addressed.
8) Charlie brings up the issue of conservatism. Some conservatism can be a good thing. ( I propose the diver should decide how much for him/her self) Following the idea that if some is good, then alot is better, let me offer a parallel thought and then tell me if some is good, then alot is better. When the speed limits were lowered to 55, the insurance companies loved it, accidents rates were lower, and the severity was lower. If we lowered them to 45 or even 35, there'd be even less accidents and they'd be even less severe. seems most drivers are willing to accept the risk level that comes with 65 or 70. Would 35 be conservative, or ridiculous on the interstate, same answer to the 10X overdrive on the cns clock
Anyway, that's my $.08 worth, thanks guys for a good thread.
Darlene