I have often heard that linux distros are used by frugal users who are trying to breath new life into obsolete machines. I am curious about any information that can be provided about generally helping old machines "be all that they can be". What hardware specs would you consider to be the minimum for adequate (tolerable program loading speeds and program usability) for knoppix and equivalently sized distros such as kanotix. When are micro distros the best compromise for older machines?