v1	Version 1 AT&T UNIX
v2	Version 2 AT&T UNIX
v3	Version 3 AT&T UNIX
v4	Version 4 AT&T UNIX
v5	Version 5 AT&T UNIX
v6	Version 6 AT&T UNIX
v7	Version 7 AT&T UNIX
32v	Version 32V AT&T UNIX
V	AT&T System V UNIX
V.1	AT&T System V.1 UNIX
V.2	AT&T System V.2 UNIX
V.3	AT&T System V.3 UNIX
V.4	AT&T System V.4 UNIX