They are two entirely different paradigms. The basic functionality, however, is very similar. The source repository is located on and maintained by the server, along with various accounting mechanisms such as user management, system logging, and permissions control. The server also has various duties such as maintaining versions and tracking changelists. Perforce uses the concepts of depots and clientviews to describe the relationship between the server and client environments.
Depots describe a section of the whole repository.
A depot is generally created for each project managed by the server. Clientviews are user-defined views into the repository. They can be composed of one or more depots, or smaller selections of them, allowing a tremendous deal of flexibility. Each user can have one or more clientviews defined, and switching between them, akin to switching between workspaces, is as easy as changing the value of an environmental variable. All operations between the client and server are performed using a command line program named 'p4'.