A computer connected to a network can take on any one of three roles
Client/Server computing describes a network transaction where one computer, the server, provides a network resource and a second computer, the client, uses the resource. The alternative to client/server computing is peer-to-peer computing, where all of the computers involved both provide and access network resources.
Client and Peer computers generally have simalar hardware and sofware configurations. A typical configuration would be a midrange PC using Windows 95 or NT Workstation. A Server would generally have more advanced hardware, like SCSI disk drives and extra memory, and use a server operating system like NT or Novell.