I was doing a trawl of related Unix source trees, and found that some early
C code from around 2nd Edition Unix is still in OpenSolaris today:
http://minnie.tuhs.org/cgi-bin/utree.pl?file=V2/cmd/if.c
Choose: Compare this file to OpenSolaris_b135/cmd/fmli/sys/test.c
and then click on the Side Scroll or the Printable button.
There's about 15 lines of code in common between the 2 files.
Cheers,
Warren