UNFS3 is a user-space implementation of the NFSv3 server specification.
It provides a daemon for the MOUNT and NFS protocols, which are used by
NFS clients for accessing files on the server.

It can be configured to run under an unprivileged user account, can password
protect its exports (even with one-time passwords), and supports ClusterNFS'
file tagging features.

unfsd conflicts with knfsd (the kernel-mode NFS server) if both are configured
to listen to the same port, which defaults to 2049.

Slackware Linux 11.0 ships with knfsd, however that defaults to disabled.
To use this NFS server instead, make sure /etc/rc.d/rc.unfsd is executable and
/etc/rc.d/rc.nfsd is not executable.  Add the following to /etc/rc.d/rc.local:

# Start the NFSv3 service
if [ -x /etc/rc/d/rc.unfsd ]; then
  /etc/rc/d/rc.unfsd start
fi