Pdbsql provides three samba passdb backend modules: pdb_mysql, pdb_pgsql, and pdb_multi. pdb_mysql is a MySQL passdb backend. pdb_pgsql is a PostgreSQL passdb backend. pdb_multi is a backend which loads multiple passdb backends. These are provided because support for MySQL and PostGreSQL passdb backends has been removed from the Samba source tree, due to lack of an active maintainer.
Print Release System provides Web-based management of System V printing. It sits between Samba and the System V printing system. It ought to be relatively easy to make it work with other printing systems. After the job is printed, the user needs to consult a Web page that shows their queued jobs, which can be selected and released for printing (or canceled). A record is maintained for each job and, once the user reaches a quota, they can't release any further jobs to the printer.