Subject: Re: MI APM support
To: Matt Thomas <>
From: R. C. Dowdeswell <>
List: tech-kern
Date: 08/11/1999 14:36:18
On 934380966 seconds since the Beginning of the UNIX epoch
Matt Thomas wrote:
>At 06:28 AM 8/11/99 , Nathan J. Williams wrote:
>>I have a minor concern: APM is specifically the name for the
>>power-management system used on i386 boxes; does it make sense to call
>>power management facilites on other systems (like your SPARC) "APM"?
>> From what I know of APM I have to believe that the SPARC power
>>management mechanisim is totally different.
>>Is the apm(4) interface actually appropriate for the SPARC's power
>>management facilites? How close a fit is it? 
>For the Tadpole, it's a fairly good fit.  The only thing that doesn't 
>fit is Standby mode.  But it can be simulated.  The hardest part will 
>be implementing suspend (since the kernel needs to write the contents
>of physical memory to partition e (almost like a crash dump)).
>Matt Thomas               Internet:
>3am Software Foundry      WWW URL:
>Cupertino, CA             Disclaimer: I avow all knowledge of this message

This would be great even for non-laptops.  It would be really nice
to be able to power down a machine and add a UPS without necessarily
killing everything that the machine is doing.  Considering that my
AS 200 boots in under a minute, one could probably add a UPS to it
without the user's connections being lost, even.

More tricky would be moving the computer from one room to another,
but if one has it on rollers, it could be done.

I think that a lot of questions are begged, though, one would
certainly have to be pretty careful about one's devices, they tend
to have a bit of state in them.  And then another issue would be
what to do if devices get moved at all.  It would be great to switch
VGA cards without a "reboot".  But moving devices around would, in
all likelihood, be a bit of a nightmare.

One might be able to get around some of these problems by saving
the autoconf setup on the disk and treating it as wired down devices
so that one could be sure to put all of the existing devices back
into their original positions.

It does sound interesting, though.

 == Roland Dowdeswell                      http://www.Imrryr.ORG/~elric/  ==
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