If so, that would have been NeXTStep. BeOS was (mostly?) POSIX compatible, but was less of a Unix than Linux.
John Perry Barlow described it: "I have a NeXT machine -- I expect a boo or two -- that's as close to UNIX as I've been able to get, and that's kind of like UNIX with training wheels by Armani." http://shop.oreilly.com/product/9781565929920.do
John Perry Barlow described it: "I have a NeXT machine -- I expect a boo or two -- that's as close to UNIX as I've been able to get, and that's kind of like UNIX with training wheels by Armani." http://shop.oreilly.com/product/9781565929920.do