It's important to remember that 1st, 2nd, 3rd,
... represent editions of
the *manual*, and that there is no guarantee that any particular
snapshot of the system corresponds exactly to what was in any particular
manual edition. Research Unix (as it was later called retrospectively)
was right up to the end a continuously evolving system, and the whole
concept of releases simply did not exist for it.
I thought there were distinct releases for 5th and 6th (and 7th?)
edition where the manuals, sources and binaries were all collected
in a consistent snapshot and released as a unit.
John Cowan
http://www.ccil.org/~cowan
cowan(a)ccil.org
Tim Newsham
http://www.thenewsh.com/~newsham/