[SOLVED] Dual boot with ubuntu w/o installing GRUB? (YES)

Question

Hi all -
This is my first shot at arch, tho I've installed a few other linux distros.
So far I really appreciate the excellent documentation, especially compared to other linuxes!
But I can't find a good answer to this question:
I already have ubuntu installed and would like to dual-boot with arch.  (I also have Win7 but boot it from a separate disk selected via BIOS, and usually leave this disk disconnected anyway, so it's not an issue; grub doesn't know it exists).
Q:  Before installing, can I make a new LOGICAL ext4 partition (say /dev/sda7),
- then install arch on that **w/o installing grub** and **without messing with the MBR**,
- then edit ubuntu's existing menu.lst to add arch to the boot options?
Current $ fdisk -l
/dev/sda1    ext4 primary/boot (/ for ubuntu)
/dev/sda2    extended
--/dev/sda6  linux-swap
--/dev/sda5  NTFS (data - mp3s, etc)
unallocated  480GB  --> Create new ext4 partition /dev/sda7,  (logical or primary? Prefer logical)
Current menu.lst entry that I normally boot:
title       Ubuntu 12.04 LTS, kernel 3.2.0-24-generic REGULAR
uuid        UUIDforSDA1 (file has actual UUID number...)
kernel      /boot/vmlinuz-3.2.0-24-generic root=UUID=UUIDforSDA1 ro
initrd      /boot/initrd.img-3.2.0-24-generic
and add something like this to menu.lst:
title  Arch Linux
uuid  UUIDforSDA7
kernel /boot/vmlinuz-linux root=/dev/sda7/ARCH ro  (??? - from example in arch docs)
initrd /boot/initramfs-linux.img
or
kernel /boot/vmlinuz-linux root=UUID=UUIDforSDA7 ro  (??? - like the ubuntu entry)
I'd really like to NOT mess up booting ubuntu!  (Another option might be install arch to a separate disk with the ubuntu disk disconnected, then copy the whole install over via a USB adapter...I've done worse!)
TIA for any help!
Edit: so I guess there's three questions:
1 - Can I install arch w/o installing grub & MBR messing-wth?
2 - What's the correct syntax for menu.lst to access and boot arch?
3 - Will this work?
Last edited by Flemur (2012-05-25 15:24:18)

Answer 1

Well, it worked and booted up first time - no grub install.
The main hassle was merely creating a new ext4 partitions because "Partition Wizard" boot CD screwed up and I kept getting "Unable to update kernel until reboot" messages until I deleted and rebuilt all the partitions in the extended partition with puppy linux & gparted instead of Partition Wizard.
In case others stumble upon this trhread, here's some info:
The entry in the ubuntu (original) menu.lst was this:
   title           Arch Linux
   uuid          af7...etc...9f3c
   kernel        /boot/vmlinuz-linux root=UUID=af7...etc.f3c ro
   initrd          /boot/initramfs-linux.img
I'm even posting this from arch/fluxbox/Firefox, although getting X set up with nvidia (PITA!) apparently required using a different pacman source:
File "mirrorlist" now points to
    Server = http://mirror.us.leaseweb.net/archlinux/$repo/os/$arch
which wasn't in the original file.
Then
$ pacman -Su --> "/etc/mtab exists" --> delete it and something else broke,
so
$ pacman -Su --force --> worked fine (against official advice)
Also: needed to install nvidia-utils and xorg-xinit
Thanks again!