[PATCH] Poseidon MK6 import

Dirk Hohndel dirk at hohndel.org
Mon Oct 27 07:34:36 PDT 2014

Good morning...

On Mon, Oct 27, 2014 at 08:42:12AM +0100, Robert Helling wrote:
> > Robert appears to have stepped up to help our Willem to get this right,
> > but the more people work on this and help figure out what's the right way
> > to do things, the better.
> indeed, more people needed here. I cannot say I have any sort of
> overview about the recently added CCR functionality. I have only only
> spent some time on debugging to make sure features that worked before
> got unbroken again. And of course, I don’t dive rebreathers myself
> (currently I am not diving anything unfortunately, stupid flu!) so all
> my knowledge is from hearsay anyway.

So who are the rebreather divers besides Willem who are helping to get
this right and are especially testing this as thoroughly as possible.

I'd hate to release 4.3 and announve rebreather support and then have to
say "never mind"...

> Re the compression thing: I agree it should not be in memory, only when
> saving files. And then repeated values should be omitted rather than set
> to zero as zero has a special meaning: Zero set point indicates that we
> are on OC and shortcuts all CCR calculations.

Exactly. I need to go through the recent patches again and figure out
where this was added. I was definitely too relaxed accepting rebreather
changes, but I figured this was the best way to get stuff in and get
people to start testing, given the challenges we had to get patches to
work in the first place.

> BTW, another thing that need some looking after (for which I did not
> have time, yet) is when we calculate SAC rates: For the PSCR code, that
> I submitted on Friday, the steady state value of pO2 depends (amongst
> other things) on the current SAC. But often enough (at least when I was
> testing) it had not yet been calculated so the pO2 calculation has to
> resort to the default value (see the first if() in the code). My
> impression is that in many cases, there should be enough data to have a
> SAC but we only calculate it later in the code path. This is
> particularly bad, since we have two different default values for SAC,
> one for bottom time and one for deco, except that for real dives (those
> downloaded from dive computers) this distinction does not make sense.

I'm still unclear how we are calculating the SAC in the PSCR case.
So I can't quite tell you where this should be done.

I repeat my question from above - who else on this list dives rebreather,
understands the logic behind all this and can help get this right?


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