[TriLUG] Laptop Linux

[Mike Mueller]

On Saturday 13 December 2003 09:56, Jon Carnes wrote:
> On Fri, 2003-12-12 at 19:50, Phillip Rhodes wrote:
> > > Anybody have measurements on how long a battery charge lasts using
> > > Linux on a laptop?
> > >
> > > What I conclude from reading this is that Linux control of ACPI ...
> > > well ... er ... sucks right now.  I'll continue to research this, but
> > > if anyone has information to the contrary I'd like to see it.
> >
> > Mike,
> >
> > I don't have any data for you at the moment, but if it's really
> > important to ya, I could generate some. I've got my laptop configured
> > to dual-boot RH 9 and Win2K Server, so I could easily do a comparison
> > and chart out the battery life times...  As it happens, I can't really
> > speak to the battery life under Linux, as I'm usually near an AC source,
> > and have never let my battery run all the way down...
> >
> > TTYL,
> >
> > Phil
>
> I have an interesting story that is along those lines.  I bought some
> old Laptops for $25/each (old Toshiba P233's) and to test/retrain the
> batteries I charged them up and then ran them out a few times using the
> current OS, Win98.
> I thought the batteries were in fairly bad shape as they wouldn't hold a
> charge for longer than about a half hour.
>
> I installed Mandrake 9.1 and RH9 on the laptops, and while at a clients
> ended up having to run them off batteries - they each lasted over 2
> hours... which I found to be fairly amazing.

Agreed.  For that class of machine - probably using APM.  4-6 hours is my 
expectation for brand-new laptops.
>
> From the very beginning the BIOS settings have been set to use maximum
> power for CPU, disk, and screen.
>
> My guess is that the Win98 was hitting the disk quite often (for reasons
> unknown) and that ate up the power.  The apps I was running on Linux
> basically read the hard drive on start up and then ran fairly well right
> out of RAM.
>
> Anecdotal evidence...

My old Presario was running ME when the new replacement battery would not 
last more than 45 minutes.  I wish I had paid more attention to battery 
charge management when I was running Mandrake 8.1 with the original equipment 
battery.

I noticed that the Knoppix distro on my new Toshiba used and found the APM 
routines.  I don't think APM can control screen brightness so the screen 
stays on high intensity all the time. With the Toshiba Power Management tool 
under XP I see controls for display intensity, display on/off, cooling 
scheme, CPU speed, HD, sleep, and hibernate. It's reasonably predicable that 
the new Toshiba running XP will last longer than the same machine running 
Linux. 

The Toshiba Toolset also had a configurator that distinguished 3 user groups: 
road warrior, student, SOHO.  Those distinctions got me thinking.  If Linux 
lags in the battery charge management arena, then that critical student group 
which values maximum charge preservation will opt away from Linux and that's 
not good for Linux on the desktop bacause the desktop class is being replaced 
by laptops.  
-- 
Mike Mueller
324881 (08/20/2003)
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