Could we get a discussion going about computer redundancy *?
I am thinking about having a partition just for a 'back up' operating system, like linux and windows running. The thought is incase one partition has errors (e.g. windows) the other operating system will allow me to still have a running pc.
Could I be able to repair the partition that has the errors on it? e.g. ubuntu repairing windows
Ever since I've had Vista I haven't had to repair/reinstall windows even once. Big difference from 98SE where I had to format & reinstall monthly. There is probably very little benefit to having a second OS to 'fix' a first OS install, what with safe mode or recovery DVDs, possibly in combination with restore points. The only benefit I can see is - if you have only the one PC - a second, still-working OS would give you internet access to get help on fixing the broken OS, and give you a different environment for urgent work/mailchecking/etc.
Personally my hard drive is always nearly full so to me the space saved by not doing this far outweighs the small comfort of a second OS. Plus, if an OS does break, a second OS still means you have to fix the broken one.
I'm under the impression dual-booting is mainly for developers or linux-fans who want to play windows games that WINE won't run. Your idea's not without merits, but it's certainly not for me.