CentOS 6 and 7 both boot up and seem to work just fine on the Dell Latitude E6420, which is a 2-3 year old model frequently available 'refurbished' for quite cheap from lease returns. That specific model is a 14", and has an optional 1600x900 screen (which I advise, the default 1280x600(?) screen is just too low resolution to be useful). 2nd generation Core I5 typically, 8gb ram typically, nice and rugged, albeit a bit heavy when compared with an ultrabook. -- john r pierce, recycling bits in santa cruz