On Feb 5, 2012, at 1:38 AM, Hendrik Jan Thomassen wrote:
If I recall well the /sbin directory first appeared in HP/UX,
and the name stood for 'Static binaries'.

Do you recall when this was?

4.3-RENO has the bin/sbin split, and that was 1990, but the split isn't yet in 4.3-Tahoe, which was in 1988.  In 4.3-RENO it was already system binaries since 4.3 didn't have shared libraries, at least according to the TUHS 4.3-RENO archive

http://minnie.tuhs.org/cgi-bin/utree.pl?file=4.3BSD-Reno/src/share/man/man7/hier.7

I don't have a copy of the BSD SCCS trees to narrow the split down further...

Perhaps this indicates multiple invention?

Warner