RZ23 setup on DEC3100 Station

[mf]

We have been able to use successfully only one RZ23 per DS3100 and have
significant space left on it.  This was done essentially by NFS mounting
/usr/etc, /usr/bin, /usr/lib, /usr/man, /usr/ucb from one NFS server.  

This has to be done carefully, since some of the programs in /etc which are
links to ../usr/etc are needed at boot time.  Anyway, our local /usr
is down to 31 Mb (incl. var).