Subject: Re: New power management framework for sysmon
To: David Maxwell <>
From: Steven M. Bellovin <>
List: current-users
Date: 04/21/2003 13:59:43
In message <20030421171018.GQ12714@vex>, David Maxwell writes:
>On Mon, Apr 21, 2003 at 09:24:15AM -0700, Jason Thorpe wrote:
>> On Monday, April 21, 2003, at 07:54  AM, Ignatios Souvatzis wrote:
>> >Whether software interupts are handled by the BIOS or the kernel 
>> >doesn't
>> >change much ... although I guess the kernel is a bit more likely to go
>> >incommunicado. You (kernel) switch the fans off, block interupts,
>> >go into a tight loop -> the machine will melt, right?
>> But you can't really have it both ways.  If you're handing power 
>> management related traps/interrupts, the firmware can't be.
>Well, the software could have been allowed to configure the settings,
>then the firmware could be in charge of operation. In that way, you
>could get the best of both worlds.
>The other option would be for the firmware to have a watchdog-like
>behaviour. If the OS doesn't poke it periodically, it escalates the
>cooling (or powerdown) state, to be safe.

Hmm -- guess I'd better get working on my software watchdog timer 

>> If you want to leave a machine like that unattended for the weekend, 
>> then make sure the fans are on.  Such machines tend to be servers or 
>> non-laptop workstations anyway, right?

My laptop tends to stay on all the time....

		--Steve Bellovin, (me) (2nd edition of "Firewalls" book)