Peter writes: >> A better approach is to be able to boot whatever slice you >> want without having to change the active slice. >> >> NetBSD can do this. The MBR puts up a menu of the bootable >> slices on the disk being booted. You can allow the timer >> to time out and boot the default. Or you can enter the number >> of the slice you want to boot. Or you can type a function key >> F1 F2 ... to boot a different disk, and it will load the MBR >> from that disk and run it. There is an alternative for keyboards >> without function keys.
> So can FreeBSD - though only for MBR If so, the documentation could use improvement. Examples would be great. > - this functionality doesn't seem > to have made it into the GPT bootcode. Is anyone working on this? MBR is only good for 2 TB and the 3 TB disks are becoming cost competitive. I've switched over to GPT for everything except boot disks, as it is less brain damaged than MBR. >> And it works great. Except that one of the 27 stages of boot >> code that FreeBSD uses INSISTS on booting the active slice, >> so you can tell the MBR to boot slice 3 and slice 3's boot >> code sees that slice 4 is active and boots slice 4. > > Multibooting worked correctly when I last used it (a few years ago). > Have you raised this as a PR? No, partly because I haven't had much luck with PRs. Mainly because I'd rather spend my time trying to migrate to GPT than improving MBR. So many bugs/misfeatures so little time, >> RS-232 console + hardware modem + POTS = remote console > > And even that doesn't fully work unless you have a serial-aware BIOS. Real computers have RS-232 consoles. If you neglected to specify RS-232 console in the requirements, there is this thing. I haven't tried it. http://www.realweasel.com/ Somebody probably sells a KVM-over-IP box. You could see if openbios supports your mainboard. John writes: >> And it works great. Except that one of the 27 stages of boot >> code that FreeBSD uses INSISTS on booting the active slice, >> so you can tell the MBR to boot slice 3 and slice 3's boot >> code sees that slice 4 is active and boots slice 4. > > There are only 3 stages, It feels like more. :-) > and boot1.S is what looks at the active slice. > Unfortunately it doesn't have a better way to do this as the only input it > gets from boot0 or any other MBR boot loader is the BIOS drive number in %dl. > I'm not sure how else you would detect that a non-active slice was booted > from > when that is your only input. The NetBSD boot code manages to do it. _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
