Mac OS six is back there with DOS 2.6, mate. Any active Mac user today is likely to be using Mac OS 8.x at a minimum, more likely to be using 9.x. There is a marked population who have not made the migration to 10.x because it is a fundamentally different OSarchitecture (UNIX based) and a much bigger change to a user. Even with a fairly old Mac you can run OS 8.x -- depends on HOW old, of course. IF he is still driving an old 80086 machine like a Classic or a II before the advent of PPC chipsets, he may have stuck back at 6.x but if so he's a rara avis indeed.

A