[openbeos] NewOS and ACPI/OSPM support
- From: Mark-Jan Bastian <markjan@xxxxxxxxx>
- To: openbeos@xxxxxxxxxxxxx
- Date: Wed, 12 Dec 2001 10:45:48 +0100
Hello,
BeOS is very bad at supporting powermanagment features. If you run
a mobile PIII, and pull out the power, the scheduler doesn't work
correctly anymore - audio sounds bad, and latencies aren't guarteed
anymore. This is (as far as I can see) due to the BIOS's software
that reduces the speed of the CPU (intel speedstep) when running
on battery. In theory, with NewOS we could tell the timer at exactly
the right time when the speed was changed, so that the scheduler and
all other tasks that rely on the timer continue to work correctly.
Also, BeOS has no powermanagment features in it's device drivermodel,
so that saving power at the videochipset, LCD or CRT screen and/or
drivers, modem and sound chipsets etc is not supported. Having
an indication of how many watts every component takes, would be
very nice for estimation of battery life, and for determining when
the system has to be shut down, and how much power is needed for
that graceful shutdown/hibernation procedure.
Spinning down a harddrive is not supported, neither are
there ways to minimize disk-spinup for a certain filesystem, for
example, by postponing disk-writes, if this is supported by
the block cache and filesystem architecture.
Also, hibernation is not possible, but maybe not wanted either
in the way windows supports it. Saving 256 kByte of RAM to
disk would be a quite long process, so maybe a better solution
would be an API for applications to stop their threads, and
deallocate as much memory as possible, and letting the kernel
only write the used pages of memory to disk.
Most species on this earth are pretty efficient in using energy
(except for one), so lets make a piece of software/OS that
competes on being efficient. Flipping the fixed amount of
transistors in a given hardware configuration, fewer times
whenever possible.
Mark-Jan
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