Can I install linux on an external hard drive and boot from there?
 

I am fed up with windows. I just bought a new Toshiba M10 and don't want to risk voiding my warranty. Also I only have moderate computer skills. I experimented with a linux live cd on my old compaq presario and liked it very much. I am hoping that by installing linux on a hard drive I would be able to use it with either computer. Which distribution would best lend itself to this setup?

Hey, welcome to LQ. As long as your computer has the ability to boot from a USB harddrive, you should be alright. Just make sure not to touch the windows disk during the install's partitioning phase.

This may not be so straight-forward. It should be, but may not be.
I haven't tested this, but I've seen plenty of threads where people have had the internal MBR overlaid rather than the external. It would appear the installers for at least some of the popular mega-distros can't handle the situation properly.
Can be rectified, but shouldn't need to be.

BTW, what makes you think installing Linux will void the warranty ?. I had to have the m/board replaced on a new Dell, and they couldn't have cared less as to what I had on it - several Linux distros (using grub) as it turned out.

Some computers don't have a windows install disk, or a restore disk and you need to produce restore disks yourself (based on the contents of a hidden directory). You might want to do this. Then if say your onboard NIC goes out and you need to send it in, you would restore the system before sending it in. There shouldn't be any problem then regardless of their policy.

If this is a Vista machine, I would recommend defragging and then resizing the NTFS partition using Vista's tools before installing Linux on the hard drive. When I did this, Vista was very greedy how much hard disk space it wanted for itself (only sparing about 30GB of a 120GB drive. I think my mistake was not defragging it first.

After installing Linux I used gparted to free up more space and had to repair both the Linux and NTFS partitions. I think I should have run Vista's defrag tool after resizing and retry resizing. My guess is that the MFT or other items were located at the middle of the drive preventing further reductions in size. Defragging again may have moved items toward the new middle of the partition allowing further resizing.

If you do install linux on the same disk with Windows, I would recommend manually configuring the partitions. This can prevent surprises such as accidently installing on the entire drive.

There are howto's on using the Windows bootloader to chainload linux. Vista doesn't have a C:/BOOT.INI file, but if you create one, it will use it. So you can follow the same instructions for NT or XP. If you google for "NT Linux dual boot" you should find many webpages with full instructions. This method will leave the original MBR intact while allowing you install Linux on another partition on the main hard drive.

Good Luck!