> > When I upgraded from debian woody to sarge, grub (both new and old > > versions) began to map my drives incorrectly. My "work-around" has > > been to change the root command to compensate for the mapping > > error: > > > > sda drive 0 root (hd0,0) > > sdb drive 1 root (hd2,0) > > sdc drive 2 root (hd1,0) > > > > Will this work-around cause me any problems? > > Hard to say . sometimes stuf just works for months on end without > problem . and then the next boot and you are in trouble.
Sorry, what I meant was trouble _after_ a successful boot, not getting the boot itself to complete. But you do seem to hint that mapping can change for no reason at all, and so I guess I should be less concerned that a simple upgrade to debian sarge should cause drives to be mapped differently. > Here are some examples of mappings while I was running 3 HD's sometime > ago. May be of some help to you. > > title windows xp > root (hd2,0) > map (hd0) (hd2) > map (hd2) (hd0) > makeactive > chainloader +1 I tried this approach again, but still without any luck. For example, a hard disk that is set in BIOS to be the third disk is seen by grub as the second disk. So I tried to boot the third disk: title ... root (hd2,0) map (hd1) (hd2) kernel ... This had no effect. Grub is still seeing the third disk as hd1 and tries to boot the BIOS' second disk. > > My "work-around" has > > been to change the root command to compensate for the mapping error: > > > > sda drive 0 root (hd0,0) > > sdb drive 1 root (hd2,0) > > sdc drive 2 root (hd1,0) > > This is not incorrect, OK, so I gather I can remap in this way without risk and without having to use a device.map file or the map command in the menu. > In order to change those device numbers you have to change things in > the BIOS. Understood, but my instinct is to adapt grub to BIOS, not the BIOS to grub. > > Instead of using the root command, would I do better changing the > > map, either the map file in /boot or placing a map command in the > > grub menu? I tried doing both, but without any effect. > > What do you want to do? If that is changing the mapping in > GNU/Linux (or whatever you use), change device.map. I tried putting this device.map file in the floppy /boot/grub directory: (hd0) /dev/sda (hd2) /dev/sdb (hd1) /dev/sdc This looks like it should take the disk defined as third in BIOS (sdc) and remap it to be grub (hd1). However, this does not work (I'm not sure one can add a device.map file to the grub boot floppy). What do I want to do? I gather there are four methods to take care of a mapping issue: a) reorder the drives in BIOS (but then grub would just get them wrong again, I suppose), b) use a map command in the grub menu stanza (tried, but had no effect), c) add a device.map file to /boot/grub (tried, but had no effect), d) the method I used successfully is simply to point the root command at what grub incorrectly thinks is the correct disk (so, for the third disk, I use `root (hd1,0)'). The problem is that I've never seen mention of my method (d), and so I'm concerned that I may not get a clean boot. The reason for my concern is that I see peculiar message during boot (although dmesg at the end looks OK) and, more seriously, I'm have problems installing an X Windows system. I skip specifics about these things here, but only need some assurance that my method (d) for remaping disks is not a possible source of difficulty. Haines Brown _______________________________________________ Bug-grub mailing list [EMAIL PROTECTED] http://lists.gnu.org/mailman/listinfo/bug-grub