Rent vs. buy back then is a lot tougher decision than it is now - If you turned your old rental unit in for the latest model because it was significantly faster

Rent vs. buy back then is a lot tougher decision than it is now - If you turned your old rental unit in for the latest model because it was significantly faster, chances were you would have to rewrite all your software. Which was the big advantage of the IBM System 360 - the same software would run (+/-) on all the models of the line.