FAM, the File Alteration Monitor, is a subsystem that applications can use to be notified when specific files or directories are changed. It is intended as a replacement for mechanisms such as poll and select. FAM comes in two parts: famd, the daemon that listens for requests and provides notifications, and libfam, a library that client applications can use to communicate with FAM. For further information on libfam, see the fam(3) manual page. famd is normally started by an Internet superserver such as inetd or xinetd, but can also be started independently. Only one instance of famd can be run at a time.