Bug: Cylinder editor doesn't honor sorting

Linus Torvalds torvalds at linux-foundation.org
Sun Dec 11 16:53:32 PST 2011

On Sun, Dec 11, 2011 at 3:20 PM, Dirk Hohndel <dirk at hohndel.org> wrote:
> Umm. Can we rename the column then, please? Having 21/30 as my
> "O2 value" really makes no sense at all.

So I'd rather not confuse people who don't know about trimix, and I
don't want to use some long and unreadable name like "EAN40" in the

IOW, for people who are nitrox divers, the O2 headign makes sense, and
allows for a simple display. They won't be confused, and it's dense
and readable.

And for trimix, quite frankly, I think that

(a) we cannot possibly make it "obvious", because even "Gas" isn't
actually true, since it's not about any particular mix (ie the
likelihood is high that you probably have two different mixes anyway -
so the numbers shown are unlikely to be *one* mix)

(b) the diver for that case is guaranteed to know about multiple
cylinders and trimix gases anyway, so I doubt he'll then be surprised
when it says "O2" but isn't a single value any more.

(c) and if the trimix person does get confused and needs to be told
what the magic X/Y format means, I think that's fine. We expect a tech
diver who does trimix to be able to internalize the odd rules. We do
*not* want some random AOW person with a nitrox card to have to be

Put another way: having a heading of "Gas" and then showing "40" would
perhaps be more "technically correct", but I think it could confuse
the wrong kind of person.

So a beginner is expected to only see "air" or some simple percentage
like "32", and in both cases I think it's ok and fairly unambiguous to
have the heading say "O2%".

And by the time the "O2%" heading is no longer really true any more,
the X/Y numbers are complicated enough that *no* reasonable heading
would really explain it sufficiently ("Max O2% / Max He %" is just
much too long).

> And then we need to be somewhat consistent so sorting makes sense?
> So air would become "21/0" and EAN36 "36/0"?

Hell no.

Again, you're thinking entirely wrong about this. It's not about some
"technical consistency". It's about PEOPLE.

And some crazy sequence like "21/0" would be a total effing disaster
to a beginnner. If you aren't nitrox-certified, you'd better not see
*any* percentages at all. The only thing you will ever see is "air",
and that's fine, and as it should be.

And if you are nitrox-certified, a number like "21/0" doesn't make any
sense. So a tool that shows that kind of numbers is a *crap* tool.

Which is why we show things the way we show them. Air is "air" - it's
not "21% Nitrox", because a user of air might just be scared/confused
by percentages and nitrox - it just doesn't make sense at that level.
And EAN40 is 40 - it's not "40/0", for the same reason. The "/0" would
only confuse people who don't have the background to understand what
it is.


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