On Wed, Nov 7, 2018 at 3:38 AM <arnold@skeeve.com> wrote:

I'm not sure what you're asking.  When DNS came along, it became
a matter of editing /etc/nsswitch.conf to include dns as one of the
options along with files and yp/nis.

This does not align with my memory at all. I was at udel until 1988
and we started dealing with dns ca. 1986, and the shared library stuff
I dealt with in sunos came later.