[Nut-upsdev] Some questions on driver implementation and variable names

Carlos Rodrigues carlos.efr at mail.telepac.pt
Sun Feb 25 21:33:42 CET 2007


On 2/25/07, Arjen de Korte <nut+devel at de-korte.org> wrote:
> Based on made up 'information'. I'm not doubting your good intentions
> here, but I'm quite worried that we're on a slippery slope. I'd rather
> not present data if we're not sure it is reliable.

I don't think it is even possible to calculate an accurate value,
there are too many variables. However, if the function is chosen by
the driver, it can be any function that gives a close enough
approximation to the real thing, given the class of hardware it is
driving.

> > "megatec", for example, calculates "battery.charge" itself, and it
> > sucks at it too... clients would suck even more...
>
> This is exactly why I think we should refrain from reporting anything
> that is not coming from the UPS itself.

megatec.8 actually has a reference to the "bogosity" of the reported
battery charge :)

You are underestimating how important it is for the user to have
values for this kind of stuff. Even if they are very inaccurate
ballpark figures, the users need to know if their UPS is "almost fully
charged", or "mostly discharged". Users don't think in terms of
battery voltages, they think in percentage, even if that percentage is
just a linear function on the battery voltage.

-- 
Carlos Rodrigues



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