Use a Computer or BT?

[TSandM]

Well, I guess what I was saying is that I DO use a form of table, and one which is useful in dynamic situations, but I am also acutely aware of its potential shortcomings. So if my computer and my calculated deco are close, I'm happy. If they are way apart, I at least ought to examine my assumptions and look at whether I am dealing with a situation that falls outside the parameters where the RD curve plotting is valid.

 

[rongoodman]

I have no idea what you mean by this. Can you elaborate?

The Shearwater has a list of active deco gases, and it wants to use the richest one it can in its calculations while keeping the ppO2 at 1.6 or below. As I mentioned before, it will alert you by changing the gas display should you forget to switch. (This can bite you if you have active deco gases programmed that you're not actually carrying, since it calculates the displayed Time To Surface assuming they're there. If you spend 30 min at 150' with 50% and 100% active, for example, it will tell that you have a TTS of 27 min with GF 30/85. If you don't have those gases available, the computer will happily let you deco on air, but it will take an hour! Big difference, hope you have enough gas to do the deco.)

 

[PfcAJ]

Well, I guess what I was saying is that I DO use a form of table, and one which is useful in dynamic situations, but I am also acutely aware of its potential shortcomings. So if my computer and my calculated deco are close, I'm happy. If they are way apart, I at least ought to examine my assumptions and look at whether I am dealing with a situation that falls outside the parameters where the RD curve plotting is valid.

RD is not a table.

 

[EFX]

I read through the Shearwater Petral dive computer manual and found it quite enlightening. I liked the idea of selecting between the Buhlmann and VPM-B decompression models and displaying the tissue loadings in real time on a graph. I found this disclaimer amusing:

"This computer has bugs. Although we haven’t found them all yet, they are there. It is
certain that there are things that this computer does that either we didn’t think about,
or planned for it to do something different. ....." [emphasis is mine]

Gee, was the marketing guy on sabatical !?! Somewhere in a dive shop:

Sir, you can choose between this technical dive computer over here or this buggy one. Which would you prefer? Ummm.... let's see, it's a hard decision but I'll take the buugy one!

 

[rongoodman]

The tissue loading graph is slick. I was glad to see it added the my Prism 2 controller(Shearwater Predator) in the recent firmware update.

 

[Lorenzoid]

I read through the Shearwater Petral dive computer manual and found it quite enlightening. I liked the idea of selecting between the Buhlmann and VPM-B decompression models and displaying the tissue loadings in real time on a graph. I found this disclaimer amusing:

"This computer has bugs. Although we haven’t found them all yet, they are there. It is
certain that there are things that this computer does that either we didn’t think about,
or planned for it to do something different. ....." [emphasis is mine]

Gee, was the marketing guy on sabatical !?!

The Legal guy was apparently there while the Marketing guy was on sabbatical. I really applaud Shearwater's disclaimer that "This computer has bugs." I can't imagine a dive computer or any other complex software-based device that does NOT do something, however minor that thing may be, that the programmers didn't or couldn't anticipate. Only a consumer well informed enough to understand that a computer very well may have bugs should be buying it. If someone demands and expects a "bug-free" computer, they're probably not of the technical diving mindset anyway.

 

[EFX]

The Legal guy was apparently there while the Marketing guy was on sabbatical. I really applaud Shearwater's disclaimer that "This computer has bugs." I can't imagine a dive computer or any other complex software-based device that does NOT do something, however minor that thing may be, that the programmers didn't or couldn't anticipate. Only a consumer well informed enough to understand that a computer very well may have bugs should be buying it. If someone demands and expects a "bug-free" computer, they're probably not of the technical diving mindset anyway.

How true. The legal guys are always there taking us to the brink of shear stupidity. At a popular fast food store (I won't mention the name to protect the guilty) you order a hot drink and they give you the sleeve first and then hand you the hot drink. When I mentioned the obvious fact that taking the drink might burn me, then what is the point in getting the sleeve if its not already on the drink?! The response was that that was ordained by corporate. Handing you a drink with a sleeve could burn you if the sleeve breaks. So, if I put it on and it breaks its my fault -- sheesh.

My issue is not with the disclaimer; Of course they need a disclaimer we live in a litagacious society. But there is a difference between saying there is a bug and there might be a bug. Shearwater's rank candor is simply not necessary. The implication is one of neglect. It's also conceivable that the software is bug free however improbale that may be so why eliminate that possiblity. How 'bout rewriting it like this:

"This computer may have bugs. Although we prerform exhaustive tests in and out of the water to remove bugs in the software,
it is possible certain bugs may remain. Please report any issues you have and we will do our best to fix them."

 

[rhwestfall]

its a Canadian thing..... humor them or they might stop sending us good beer.....

 

[Lorenzoid]

. . .

My issue is not with the disclaimer; Of course they need a disclaimer we live in a litagacious society. But there is a difference between saying there is a bug and there might be a bug. Shearwater's rank candor is simply not necessary. The implication is one of neglect. It's also conceivable that the software is bug free however improbale that may be so why eliminate that possiblity. How 'bout rewriting it like this:

"This computer may have bugs. Although we prerform exhaustive tests in and out of the water to remove bugs in the software,
it is possible certain bugs may remain. Please report any issues you have and we will do our best to fix them."

Now that I think about it, maybe the Legal guy AND the Marketing guy collaborated on this warning. What you call their "rank candor" sort of appeals to me. Maybe the Marketing people believe I am not alone in that thinking. Who knows. In any event, the term "rank candor" is apt, since we all know it's nearly certain that a consumer-grade computer has some bug somewhere, not "may have" a bug. In other words, I think the probability that it does have something that could be called a bug is much greater than the probability it can accurately be called "bug-free." So why not exercise rank candor and come off looking like a Boy Scout for admitting what we all surmise is true than write your disclaimer the same wishy-washy way as every other manufacturer and have your customers view it with the same skepticism as they do every other manufacturer's disclaimer? I have no tech diving training, but it seems to me that people with a tech diving sort of mindset have no problem accepting the idea that no item of equipment can be relied on absolutely to operate as predicted under every possible set of circumstances. In summary, their brutally candid disclaimer is one more thing that makes Shearwater stand out above the rest in my mind. I can't wait to buy a Petrel (bugs and all).

 

[EFX]

.... I can't imagine a dive computer or any other complex software-based device that does NOT do something, however minor that thing may be, that the programmers didn't or couldn't anticipate. Only a consumer well informed enough to understand that a computer very well may have bugs should be buying it. If someone demands and expects a "bug-free" computer, they're probably not of the technical diving mindset anyway.

I couldn't disagree more. When I shell out $1,800 or whatever the cost is, I EXPECT a bug-free product. I get your point though, that we should know the difference between what we expect and what we really get. I've written software and I know how complicated things get when you start adding features. The bugs tend to multiply. I'd almost rather kiss a crododile on the lips as to spend countless hours debugging software. There are too many competing products out there for Shearwater to stack the deck against them before I even get a chance to wade through the wonderful features they describe in the manual.