[ Thanks to An Anonymous Reader for
this link. ]
The Network Information Service (NIS) was developed by Sun
Microsystems, and was also known as the Yellow Pages service. The
mechanics of the system are simple–the standard system databases,
such as /etc/hosts and /etc/passwd, are converted into a generic
database format (using the DBM format, an acronym that has long
since lost its meaning).“These databases are held on the NIS server (also known as the
NIS master). All of the individual databases are placed into a
named domain and then shared from the master using the Remote
Procedure Call (RPC) interface…”