I can only imagine someone trying to explain the logic on this one in some ad copy somewhere. "TSO" is the kind of name that requires its own FAQ entry just to explain, and even then it doesn't make sense.

Not for the old guys: http://en.wikipedia.org/wiki/Time_Sharing_Option. Thinking of it, you may be right about the "doesn't make sense" part.

Sometimes a story that explains a name can help spread it - provided it's funny, interesting or an otherwise memorable viral vector. TSO might not qualify.