Just curious, theoretically speaking: my spouse just got a new MacBook (White) for work. Is the version of the operating system that came with it specific for that particular model or in a pinch could I load it on my MacBook Air. Not that I would do it. That would be wrong. But I am just curious. I am still running 10.5.8, mostly because clean installs make me nervous and anything less than clean installs offends my sensibilities for clarity and order. So instead I just stick with what I have.