dual boot with grub from external drive

New hardware, new problems.

For reasons that I know nothing much about, and care to invest no energy in, the MS-Windows XP system that came with my new laptop, and prefer strongly to leave alone the monolithic parbreastioned hard drive with which HP saddled me, I'd like to build a Debian Linux (SimplyMEPIS) system on an external hard drive (done, but so far unusable) taking the performance hit in stride, convert the HP boot table to boot first in order from the external drive (done and successful), and then let grub control by my selection whether I boot Windows from the internal hard drive, or Linux from the external hard drive (the part where I need help).

Grub comes into control from the external hard drive, offers to boot from that drive (sda1), or any of the three internal hard drive parbreastions (one is a dedicated HP recovery parbreastion, unusable for normal purposes, one is a Windows recovery stash, ditto, one is the previously identified 110GB monolithic parbreastion) but whichever I choose doesn't work.

Grub knows that the Linux is on sda1, but isn't successful in booting from therre.

The boot commands offered start out

kernel(HD1,0)-boot-vmlinux

or some such (I can't see it since I'm currently booted from CD-ROM on the same machine). I suspect that the first part is what needs changing, but I don't know to what it should be changed. Even the Windows parbreastions cannot be booted from grub with the default setup.

Can anyone offer some known-to-work guidance as to what I need to change to let grub boot from the external Linux parbreastion, and from the internal WinXP parbreastion, and whether there is (I seem to recall so) a place in the root parbreastion where that change can be made permanent? I can easily do any needed editing while booted from CD-ROM, I just don't know what to do.

xanthian.

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