RE: Power Management

Klok, F.H. (F.H.Klok@research.kpn.com)
Thu, 12 Jun 1997 11:18:26 +0100

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All,

As far as power management is concerned:
I have worked a considerable time now to enhance OmniSwp (DOS key
relocation and virtual 80 column screen, ) with power management. This
is however not a trivial exercise. It is possible to program the PMU
registers like Maciej did, I made this exercise too, but there is no
real power saving as long as you don't goto sleep or suspend mode (at
least I didn't manage, but maybe Maciej did, could you post this binary?
I guess if it's small it's OK?). Besides there's difficulty in getting
back from suspend, the BIOS seems to reprogram the PMU registers in a
way that makes the OG hang sometimes.

The trick Yong Wang uses seems not work for the full 100% on my machine.
It doesn't put the OG to suspend, it merely turns the screen off and the
OG still consumes 20mA of power, where real suspend mode only consumes
700uA (according to my measurements). Maybe Yong could give some more
insight in his amperage measurements and am I mistaken, or is my OG
configured differently.

The table below gives an indication of power consumption in different
modes (according to my measurements):
(I haven't included sleep and suspend modes, since they give the same
results between PMU managed DOS and Geos)

Geos DOS PMU power managed DOS
idle 38 mA 50mA 50mA
running 120mA 135mA 135mA
idle serial prog 50mA 150mA 150mA
running serial prog 150mA 150mA 150mA

So there still is a difference between PMU power manged DOS mode and the
geos mode of operation. And I found no difference when not in sleep or
suspend mode between DOS and PMU magemened DOS.
I can't seem to figure out why this happens. I guess the only way to
achieve this is to write a fully fledged power management driver, that
could presumable also support battery levels etc.

I was planning on releasing this enhancement of Omniswp (freeware) as
shareware, only thing I wonder about is if there's any one out there
that's willing to pay a small amount of money for such a program (say
$15), because this thing takes considerable more time and effort than I
imagined.

Frits Klok
>----------
>From: Omar Downie[SMTP:odownie@uwimona.edu.jm]
>Sent: woensdag 11 juni 1997 17:17
>To: ogo@lifelike.com
>Subject: Power Management
>
>Hello Marciej & Yong,
>
>I'm extremely thankful for your products. I've longed for this type of
>control in DOS. Are your two programs compatible ??
>
>Marciej, since you've not been able to post it on a web site, can you mail
>a copy to me directly ?
>
>Thank you both.
>
>-Omar.
>

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