Unix vs. DEC, of course; been there, fought that, still got the scars.

Although there was Unix vs. Apollo (I could tell some stories about that, 
but I'm unsure about the Statute of Limitations, whereby I called an 
Apollo salesdroid a liar to his face in front of my $PHB; I survived).

And of course Unix vs. VMS; OK, they can have the commercial market...

Oh, the stories that I could tell, such as when the computing boss was 
known to be having it off with his secretary, and had to be rolled out of 
the computer room several times by the ops after he'd had a few for lunch.

∆As I said, Statute of Limitations; this stuff goes back to the 70s and 
early 80s; not to mention when I once wasted a few months with NECISA, 
whereby you did not get promoted unless you spoke Japanese (itself a long 
story).

-- Dave, at 68 after the game with many stories