From the Perforce website..
"The Perforce SCM System features comprehensive software configuration management capabilities built around a scalable client/server architecture. Requiring only TCP/IP, developers can access the Perforce Server through a variety of Perforce clients (GUIs for several platforms, Web, or Command-Line). Perforce can be deployed quickly and easily, and requires minimal administration, even for large or distributed sites.
Available on over 50 operating systems, Perforce includes version control, workspace management, atomic change transactions and a powerful branching model to develop and maintain multiple codelines."