OpenBSD Gains Centrino Power Management

In a recent email, Theo de Raadt announced support in -current for power management on the Pentium M series of processors. This allows the CPU to be throttled and therefore power saved. Additionally, dhclient was modified so that it is not necessary to find the process of the already-running dhclient and kill it before running dhclient again. This is useful for laptops that spend time roaming between different wireless networks, when dhclient is used fairly often.

Re:Before anyone comments, on linux it's cpufreq

[Anonymous Coward]

A little offtopic maybe, but I've always been curious... One of the things I love the most about my PowerBook is how it wakes up immediately when I open the cover, in contrast to my friend's Dell laptop (running Windows XP) that takes forever to wake up from hibernate. How long does it take for a Linux system with Gnome or KDE to wake up from sleep and be usable?

I have no firsthand experience in this area so I'd be interested to know. Thanks...

Re:If it's hibernating, it won't be any faster.

[Anonymous Coward]

Thanks for your informative reply. I didn't know there was a difference between hibernate and sleep. I googled around a bit and found this explanation [bcentral.com]. However, it seems that in sleep mode the battery will only last a day or two (on a Dell laptop, at least), and that's just unacceptable--my PowerBook lasts a week or more. I imagine this has more to do with the hardware than the software, however, so I guess the only way to find out how long it would take for my PowerBook to wake up from sleep under Linux and BSD would be to just try it myself. Perhaps I'll get around to it someday. :)

OpenBSD and Laptops

[Sloppy]

Anyone have any recommendations for a laptop, for which the built-in stuff (particularly wireless interfaces) is supported by OpenBSD?

I don't care much about processor speed or fancy video (as long as XFree86 works with it). Just need to run a web browser and an IMAP client.

I think this OS might be a good choice for laptops, since those tend to get connected to hostile networks without a friendly firewall between me and "them."

I would also want an encrypted /home, at a minimum, since lightweight computers are more vulnerable to loss/theft than typical desktops. (And my home dir would contain config files for my IMAP client, which would contain authentication info.) OpenBSD can do that, right?

Re:OpenBSD and Laptops

[damian.gerow]

Have you looked into FreeBSD? 5.x is coming along {nicely,horribly}, and has GEOM, CPU throttling, ACPI, and pretty extensive hardware support. It's also got a more modern compiler, which has caused some small issues with OpenBSD (namely, PowerDNS won't compile and/or run).

Don't get me wrong -- OpenBSD definitely has its place, but it's possible to secure /any/ OS. And these changes to dhclient most certainly /would/ be welcome. But I know that FreeBSD has native support for low-level encryption, and that seems to be pretty important for laptops. I also find FreeBSD makes a better desktop, but that's a matter of personal choice.

Re:OpenBSD and Laptops

[jschauma]

Dunno 'bout OpenBSD, but NetBSD [netbsd.org] will certainly be a good choice, too. See this page [reedmedia.net] for some reports of NetBSD on laptops.

As for encrypted /home, take a look at NetBSD's cryptographic disk [netbsd.org] driver. I use it on my IBM T30 to encrypt /home and swap. Neato.

Linux and Pentium-M

[lonesometrainer]

I don't know. 3 months age we bought 4 Thinkpads T40p, mainly because of the incredible batterie times everyone seemed to be experiencing with these machines. Kernel 2.6+ACPI+cpufreq+some tricks from several mailing lists give us max. 3h with display set to darkest level and bios settings to max battery life.

Windows may not be able to fine-control the machine as much as you can with the upper configuration, but a xp-test-installation kept the machine up and running for nearly 5 hours (nearly same work on the machine...).

Any tips from Linux Pentium-M experts???