API redesign progress

[Jef Driesen]

On 2012-07-05 19:47, Artur Wroblewski wrote:
> On Thu, Jul 5, 2012 at 4:21 PM, Jef Driesen <jefdriesen at telenet.be> 
> wrote:
>> I think we can consider adding ppO2 to the list of supported types. 
>> It's
>> probably mainly relevant for rebreathers, where the traditional 
>> concept of
>> gas switches doesn't exist and the actual breathing gas changes
>> continuously. For open circuit and also semi-closed I think, there 
>> is no
>> ppO2 sensor and I assume the value just gets calculated from the
>> pre-configured gas mix and current depth?
>
> It is for rebreathers indeed. You will have averaged (I believe)
> ppO2 from multiple sensors, but I suspect some computers
> might report ppO2 from all sensors on top of that. Note, that
> some of sensors might be in error.
>
> (please note I am not a CCR diver)

I'm not a CCR (or SCR) diver either. I know the basic principles, but 
that's about it.

> I know you can estimate (or recalculate) a lot of values,
> but I am interested in what my machine reported to me
> at given time and depth. I am _not_ interested what some
> application thinks, even if it provides quite accurate
> information. Actually... I am interested in the dive computer
> data when it is innaccurate. :)

The primary use-case for the libdivecomputer library is a general 
purpose logbook application (like macdive, divinglog, etc), which is not 
tied to a specific model of dive computer. None of those applications 
will ever support every single feature of each dive computer. The goal 
is to support a good subset that will satisfy the majority of the users. 
It's a trade off you have to make.

If you want to squeeze out every single piece of information, then you 
are in fact looking at a highly device specific application (like 
ostctools), not some general purpose application. You can still use 
libdivecomputer for this purpose, but it will require some additional 
effort too. For example you can use libdivecomputer for the downloading 
(which is usually the hardest task), and do the parsing yourself.

Jef