reformatting laptop & ACPI: special partitions?

Kevin Oberman oberman at
Mon May 10 15:35:58 PDT 2004

> Date: Mon, 10 May 2004 13:27:51 -0400
> From: "Michael A. Smith" <msmith at>
> Sender: owner-freebsd-mobile at
> My laptop (Sony VAIO FX-101) has been happily running FreeBSD since 4.3 
> (it's currently running 4.9-STABLE). I've never really bothered with 
> power management (apm, acpi, etc...), since I always use it plugged in. 
> That may change, however.
> I'm wiping the hard drive and installing FreeBSD 5.2.1 from scratch, I 
> want CardBus and Wi-Fi. I may also start fiddling with ACPI. I've read 
> that some laptops use special partitions to store the contents of RAM 
> when hibernating, sleeping, coma, whatever...

I'd suggest going to CURRENT. The enhancements of laptop support is
rapidly progressing and is much better today than it was when 5.2.1 was

Many laptops have a suspend to disk capability built into BIOS and
FreeBSD can use this. IT requires the creation of a special partition
(slice) which is normally done using a utility from the computer
maker. I can't say whether Sony has one. Even if it does, it must be
near the beginning of the hard drive (can't remember just how close). I
could not create one on my laptop because the NTFS partition with XP was
too big. :-(

Suspend/resume are now working for many systems, but FreeBSD still seems
to have problems with some Sonys . Suspend is a low-power
state. Basically, only RAM keep-alive is maintained. My laptop can last
for several days when in this state.

Hibernation or suspend to disk completely powers down the system.

Some systems also support a light sleep which only stops the CPU and
turns off the display. This one still drains the battery pretty quickly.

> As I recall, when I got the laptop, it did NOT have any special 
> partitions (I wiped it the day that I got it and installed FreeBSD).

Probably not as recent versions of Windows have their own, built-in
suspend files and don't rely on the BIOS capability. They save to a file
in the Windows partition. It's possible that your laptop BIOS does not
even support it.
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at			Phone: +1 510 486-8634

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