Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?
BSD Operating Systems

OpenBSD Gains Centrino Power Management 49

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.
This discussion has been archived. No new comments can be posted.

OpenBSD Gains Centrino Power Management

Comments Filter:
    • interface now seems to be Windows NT 5.x. (okay, so XP SP1 supports automatic throttling, but you can't control it)
      Yawn. 3rd party software? Bleah.
    • by 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...
      • But if it was just asleep, it takes about 3 or 4 seconds to be usable (that's about how long it takes to intialize the video and spin up the hard drive if necessary).

        It seems about consistent for linux and windows. I imagine FreeBSD is the same; I've never used it on a laptop.
        • by 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 []. 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 an
          • by addaon ( 41825 ) <> on Friday January 16, 2004 @05:48PM (#8002586)
            Yup, there are three differences between the powerbooks and (most, not all) pc laptops. First, the powerbooks are energy-star compliant, which is a goofy way of saying they draw 1W of power when suspended (on battery; they actually take about 3W when on AC, for reasons I don't quite get). This is what allows such long suspend times. Second, they don't support hibernate at all; if you're going away for vacation for a month or more, you have no choice really but to either plug in the powerbook, or shut it down; with a pc, you'd probably just hibernate it. Third, the lid switches work really damn well. There are a lot of PC's that have that, now, but it's still not consistent... the goal, just to let the pc makers know, is so that closing suspends immediately, and opening has an image on the screen before the screen is visible to the user.
  • OpenBSD and Laptops (Score:4, Interesting)

    by Sloppy ( 14984 ) * on Friday January 16, 2004 @02:00PM (#7999875) Homepage Journal
    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?

    • by lcde ( 575627 )
      I've run 3.2 and now 3.4 on my Compaq E500 Armada. Everything seems to be supported without any problems. I also have a Dlink DWL-650 wireless card.
    • by damian.gerow ( 458051 ) on Friday January 16, 2004 @02:31PM (#8000230) Homepage
      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.
      • OpenBSD definitely has its place, but it's possible to secure /any/ OS.
        I understand that, and am quite willing to consider other OSes. OpenBSD just comes to mind first, that's all.

        Have you used FreeBSD on a laptop?

        • Yes. I've used FBSD on an IBM A21m and on a T23 (don't remember which model). FWIW, I've also run Linux on both, and I actually found the FBSD hardware support to be a little bit better. However, I have not run OBSD on any laptops, so I'm not in a position to compare those two.
    • by jschauma ( 90259 ) on Friday January 16, 2004 @03:19PM (#8000811) Homepage
      Dunno 'bout OpenBSD, but NetBSD [] will certainly be a good choice, too. See this page [] for some reports of NetBSD on laptops.

      As for encrypted /home, take a look at NetBSD's cryptographic disk [] driver. I use it on my IBM T30 to encrypt /home and swap. Neato.
    • Don't know about OpenBSD, but FreeBSD-5.2 runs just fine on my Compaq Presario 2591. Everything but the winmodem worked out-of-the-box. I've never used it, but the FreeBSD GEOM system supports an encrypted filesystem.
    • by Anonymous Coward
      check out []

      i highly recommend IBM Thinkpads, in particular the X series (very portable). OpenBSD runs like a charm on most thinkpads -- many OpenBSD developers use thinkpads, so you know that the video card, etc will work ;)

    • by SteelX ( 32194 )
      Not sure if it's helpful, but I run OpenBSD on a Dell Latitude L400 (yes, it's old). Most things work, except the sound toggle buttons (I can't increase/decrease the volume via the keyboard's Fn+{F5,F6} buttons).

      If all you need is XFree86, a web browser, and IMAP client, I highly recommend OpenBSD. OpenBSD is more than sufficient. You can make a really slick desktop with it, but it does take more time to set up than Linux or possibly FreeBSD. However, you'll learn heaps as you go along.

      Disclosure: I'm als
    • If you go to the OpenBSD website and look at the pics from their 'hackathon' they are all using Apple PowerBooks. If the commiters are on PowerBooks it seems like asure bet that they support them.
  • Linux and Pentium-M (Score:3, Interesting)

    by lonesometrainer ( 138112 ) <.vanlil. .at.> on Friday January 16, 2004 @05:00PM (#8002020)
    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???

    • by drix ( 4602 )
      The XP ACPI implementation is much, much further along than the Linux's is, or may ever be. When implemented fully, ACPI can do all sorts of nifty things like shutting down individual peripherals to save power, even if they're on the USB bus (do a search for "usb 'selective suspend'" and see how many hits for Linux you get), throttle the CPU (now superceded by SpeedStep et. al), etc. Also, as much as I hate to admit it, Unix simply was never designed with this type of role in mind. It takes tons of tweaking
      • Also, as much as I hate to admit it, Unix simply was never designed with this type of role in mind. It takes tons of tweaking to get a Unix system to mimic the same basic features found out-of-the-box in Windows,

        First off, I seriously doubt that you honestly "hate to admit it". Considering some of your previous posts, I'd say you're quite anxious to say it as often as possible.

        Secondly, I really don't have any idea what you mean. Obviously those functions have to be codec into the operating system, but

  • As it is just too hard to run:

    pkill dhclient; dhclient

The human mind ordinarily operates at only ten percent of its capacity -- the rest is overhead for the operating system.