AT&T "nth Edition" vs. "Release n"

[Doug Gwyn]

In article <6798 at idunno.Princeton.EDU> subbarao at phoenix.Princeton.EDU (Kartik Subbarao) writes:
>I've seen people that use System V and the like refer to their Unix as
>"tenth edition" or "ninth edition", or whatever. I've always seen things as
>"System V release n", or whatever. Anyone know the difference between these
>different naming schemes ?

"Nth Edition UNIX" refers to "research UNIX", in use by the original UNIX
developers who are still at Bell Labs and a few selected outside sites.
"UNIX System V Release N" refers to a release of AT&T's commercial UNIX
system.  Release 4.0 is the latest that I know of.