The Net2 release was the historic 1991 release of
freely-redistributable code from CSRG at the University of California
at Berkeley (i.e., it is essentially BSD Unix, but missing some
proprietary USL code that hasn't been reimplemented).
Net2 and other early versions of BSD and Unix can be obtained from a
mirror of the Unix Archive of The Unix Heritage Society -
Fully working systems loosely derived from BSD are available from
Each of these combines a Berkeley kernel with a number of free
tools from the FSF and elsewhere.