Mail Archives: opendos/2001/04/11/00:49:04
Well, Matthias, I don't know the availability of power meters in
Germany ... However, AFAIK, they aren't available in electronics
stores in Australia (except for a "kit", about a dozen years ago ;-).
Anyway, the figures you quoted seemed rather high. You also
mentioned RMS current measurement. Both of these things led
me to think that your figures were in fact "VA", rather than "W"...
Without specific knowledge of the particular "power meter" you
used, I cannot judge if this measures true power or not ...
Just for curiosity, I decided to measure the real power consumption
of a Dell 500MHz Pentium III computer and a Samsung 17" monitor,
in _actual_operation_ ... results as follows :
PC = 64.4W
Monitor = 54.4W
Total = 118.8W
OK, now let's get "topical" ! <g>
Firstly, do you have some idea of how likely it is, that Lineo
(Caldera) will release DR-DOS as open-source, and in what
time-frame?
Have the various problems with EMM386.EXE been resolved, in
the meantime? Eg. are there still DPMI problems with DJGPP,
or VCPI problems with Causeway and others?
How "close" is the code to supporting LBA, FAT32 and LFN stuff
properly?
Are there any M$ patent problems with using FAT32 and LFN
together? If so, would the US government department which is
pursuing M$ for anti-trust, help to revoke such a patent? Why
does the patent office grant patents for stuff that is clearly not
innovative, anyway???
Is Free-DOS any good? How advanced is it on these issues?
If DR-DOS does not go open-source, can the work that people
such as yourself have applied to addressing these issues in
DR-DOS, be "ported" readily to Free-DOS?
Are there any other issues that need addressing in DR-DOS?
I'd better "shut up" now! <g>
Joe.
> -----Original Message-----
> From: Matthias Paul [SMTP:Matthias DOT Paul AT post DOT rwth-aachen DOT de]
> Sent: Tuesday, 10 April 2001 3:52
> To: opendos AT delorie DOT com
> Subject: Re: Power measurement
>
> On 2001-04-09, Joe da Silva wrote:
>
> >Wow! For an O/T, this stuff about SI/Imperial/American
> >terminology and measurements sure generated a lot of messages!
>
> I value off-topic threads from time to time, because they can help
> to create a more familiar atmosphere. However, I wished we
> would have at least a similar amount of truely DR-DOS
> related posts at the same time... It seems, there is little left
> to say on DR-DOS until Lineo will eventually make up their
> mind... Maybe there´s something we can do to help them
> making a good decision? ;-)
>
> >If you measure the RMS current and multiply by the (RMS) voltage,
> >what you have is the "apparent power" (VA), not the "real power"
> >(W). That's the reason why the "power" figures quoted below are
> >higher than expected. Now, "apparent power" (VA) is the _vector_
> >sum of "real power" (W) and "reactive power" (VAR).
> >
> > [omitted much important stuff for shortage here]
> >
> >So, the only way to correctly measure the power consumption of
> >PC equipment, is to either use a proper power meter (hard to find)
> >or use an energy meter (eg. the one at the front or side of your
> >house) and see how much energy it accumulates in one hour (if
> >necessary, run the test for several hours, then divide the energy
> >accumulated, by the number of hours).
>
> Yep, all you write is correct - I didn´t go into all the physical
> details because I considered this would be even more off-topic
> and I would have had difficulties to explain this in English,
> anyway (but it´s good to know the English terms for it now ;-).
>
> The power providers have a strong interest in keeping the
> reactive power portion (Imaginäranteil) low to reduce their
> losses and it is an issue for some of these "logo programmes",
> you usually find on the label of a device. That´s why many
> electrical devices have some capacitors and/or coils near the
> power inlets. Modern quality power switching supplies often
> have "active power correction" so that they "look" more like
> a resistive load (Ohmsche Last) to the power provider. However,
> you are correct, it must be taken into account for accurate results.
>
> I only wonder why power meters are so hard to find, as you mention.
> At least over here you can lean them (for free or for a minimal
> fee) from any power provider. More simple power meters in
> form of plug adapters with integrated electronics and LC display
> are also available in most electronics shops for about 25 - 75
> USD depending on accuracy and features (f.e. measuring over
> a longer duration of time and calculating average and peak
> values). They should have circuits to compensate for the effects
> you mentioned.
>
> BTW. I used one of them when measuring the power consumption
> of that monitor, but I guess 37 W is still an exception at the
> upper limit.
>
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