The <tt>nfs</tt> directory holds the code for the Network File System.
The code was developed from a specification of NFS from Sun Microsystems.<p>

The 4.3BSD Internals book by Leffler, McKusick, Karels and Quarterman
doesn't cover <tt>nfs</tt>. You probably don't really want to delve into
it too much, but there is an RFC around describing the protocol, but not
the code here. <p>