On Fri, 2002-11-15 at 15:04, rpgoldman at real-time.com wrote: > Munir Nassar writes: > > next time you recompile the kernel, look under IDE devices look for "Boot > > off-board chipsets first support" > > > > this _may_ do the trick, i never played with this > > Munir, > > Thanks for the suggestion. I just wanted to follow-up, because I'm > not sure I understand. Here's the question ---- why would the kernel > enter into this at all? Shouldn't it just be up to the BIOS whether > or not I can boot from the SCSI controller? I mean, by the time the > kernel is loaded, isn't the issue decided? Anyone know? Yeah, I think the "off-board chipset support" is for making a PCI card controller appear to be the primary and secondary (etc.) controllers, making the onboard IDE controllers tertiary and quaternary (or quintessential or sexy or something). There's a lot of information on how boot loaders are supposed to work on normal x86 hardware in the LILO documentation. Basically, the BIOS reads ~512 bytes of data from a boot device. That's the bootsector, and in terms of most Linux bootloaders, it's the first stage. With Linux, the bootloader then tries to find the correct device to read it's second stage from. This second stage can be significantly bigger than 512 bytes, which allows the nifty graphics and menus that we see today in LILO and other bootloaders. The second stage actually loads the kernel. With LILO, the "LI" is usually written to the screen by the first stage, and the second stage writes "LO". There are several things to be concerned about when setting up a boot loader: Where to write the bootloader so the BIOS will load the first stage, ensuring that the second stage can be loaded, and ensuring the second stage can find and load a kernel. Usually this is relatively simple, but mixed SCSI/IDE systems and RAID controllers can confuse things. A normal PC will number off the fixed disks in a system as 0x80, 0x81, etc. In a mixed SCSI/IDE computer, it's not always possible to know what device shows up as the first disk. /etc/lilo.conf will let you specify which device corresponds to each number with disk= parameters like this: disk=/dev/sda bios=0x80 disk=/dev/hda bios=0x81 I've never been in a situation where I had to map out the devices without at least having a good guess, but I imagine a floppy with GRUB installed on it would help out a lot. GRUB can do tab-completion, and should give you a list of possible devices to boot from if you type in `(hd' and then hit Tab. If you look at what partitions exist on each drive, you should be able to determine the order that the BIOS sees them in. It might also be useful to try out the SBM bootloader (which incidentally is really useful for booting bootable CD-ROMs in older computers that can't do it themselves). Once the drives are mapped out properly, it should be a piece of cake to get LILO running. As far as I know, LILO doesn't care too much about where /boot shows up, as long as it is on a drive that is accessible at boot time. -- _ _ _ _ _ ___ _ _ _ ___ _ _ __ Floggings will continue / \/ \(_)| ' // ._\ / - \(_)/ ./| ' /(__ until morale improves. \_||_/|_||_|_\\___/ \_-_/|_|\__\|_|_\ __) [ Mike Hicks | http://umn.edu/~hick0088/ | mailto:hick0088 at tc.umn.edu ] -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: This is a digitally signed message part Url : http://shadowknight.real-time.com/pipermail/tclug-list/attachments/20021115/ca4963e8/attachment.pgp