On Thu, Sep 27, 2007 at 11:37:23PM -0500, Geoff Jacobs wrote: > Honest Guvnor wrote: > > Greetings, > > > > We would like to change the BIOS settings on our compute nodes to > > enable PXE booting which is disabled by default (AMIBIOS on Intel > > D875PBZ Pentium 4 motherboard). Reading and writing with /dev/nvram > > seems to work as expected but reboot fails because of a test against > > the checksum of the previous BIOS settings. Is there a way round this?
Some BIOSes store their setting not in 128, but 256 bytes. /dev/nvram usually sees the first half only (minus 14 bytes for the timekeeping). Obviously, the checksum calculated from 128 bytes is rarely equal to that obtained from 256 bytes :( > > The nodes have no video card, there is no support for a serial console > > in the BIOS but there are floppy disk drives. Any thoughts on > > alternative ways to change the BIOS? Even a very simplistic VGA should be standard - how would you handle a very early disk failure, or any other emergency of there's no way to read out the status of the system that's not running the OS yet? > > We have the fallback option of putting an Etherboot floppy disk in > > every node when we want to reinstall but would like to avoid this if > > we can, BTW, PXE booting would have to be enabled in two places: in the firmware part of the ethernet adapter itself, *and* in the boot order. I'm not aware of any way to do the first step without manual intervention (CTRL-S or CTRL-B) even if the second step was successful. (Some of us have asked the board/BIOS maker for a customized version, with PXE booting enabled.) > This is where the Crash Cart comes into play. You know, the one with the > tools, crimper, maybe some spare fans, etc. Usually a monitor and > keyboard as well. If there's nothing to connect to you'd be lost with even that. Steffen -- Steffen Grunewald * MPI Grav.Phys.(AEI) * Am Mühlenberg 1, D-14476 Potsdam Cluster Admin * http://pandora.aei.mpg.de/merlin/ * http://www.aei.mpg.de/ * e-mail: steffen.grunewald(*)aei.mpg.de * +49-331-567-{fon:7233,fax:7298} No Word/PPT mails - http://www.gnu.org/philosophy/no-word-attachments.html _______________________________________________ Beowulf mailing list, [email protected] To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
