I've read a lot and tried a few things, but I can't get what I've tried so far to work, and I'm still confused about parts of the boot process.
I've decided to switch distros. I used to use GRUB to dual-boot Redhat and Windows off of HDA, and all was well. I then set up Debian on another drive, the only one in the system at the time. Now, with both drives installed (Debian on HDB), I can get the GRUB on HDA to find and boot all three OS's just fine, but now I want to get rid of Redhat for the space.

The problem is that GRUB is using the configuration in the boot partition on HDA.

Here's how hda is laid out
| winxp | data | RH swap | boot | RH root |

So I guess I need to get GRUB to use the /boot directory under Debian's root on hdb1, and I need to configure it's menu.lst so it can boot Windows off of hda1. It would be nice if the automatic GRUB configuration the Debian kernel install method uses would work properly too, although I'm used to setting it up by hand.

I've already tried various things with making HDB the first boot device, but I can't get Windows /or/ Debian to load. I can provide menu.lst and the errors if you want.
Elsewise it might be best to keep using the GRUB on the MBR of hda and telling it where /boot on hdb is, or I could leave the boot partition on hda and move it to the end of the drive, but I'm afraid it would get lost.

Right, so will this work:

grub

> root (hd1,0)

> setup (hd0)

> quit

If so, how are will the partitions be referenced within menu.lst?
I'm confused about how grub/linux names things - is hd0 /always/ the master on the first ide channel and hd1 /always/ the slave, or is it contingent on which the BIOS boots from first?
Does hda /always/ corespond to hd0 ?
What's relative and what's absolute in grub.conf/menu.lst?

Okay, that worked. Thanks me.
ack, seriously though...I'll just reply to myself here in case someone is trying to do the same thing and finds this post. Setting the new root and running setup worked. Here's what I learned -

GRUB gets its labeling info from the BIOS, so if the BIOS has HDD1 as the first boot device rather than HDD0, GRUB will call it "(hd0)" even if we know, and the BIOS knows, that it is not the 1st IDE chanel master. As such it will call whatever the next hdd in the BIOS boot order "(hd1)", etc.

There are no problems with chainloading Windows using the standard
rootnoverify (hd0,0)
makeactive
chainloader +1

but I could not for the life of me get the GRUB in the MBA of hdb, when set as the first boot device, to load windows. I tried all the "map" stuff, everything, and got nothing but numerous errors or a simple hang.

Kernel paths are now of the form
/boot/grub/vmlinuz-2.6.5
where they didn't used to need "/boot" because that's what the partition was named.

GRUB version 0.93 needs a grub.conf file and doesn't know what to do with just 0.94's menu.lst.

Hope this helps someone.