Server Applications
Server applications are a special type of command line program. They are designed to start up and then wait for clients to connect to them. At that point, they provide some service. Typically they are using TCP/IP to communicate, though a SIMPOL database server program is also a server program that is waiting for connections from database clients. Any sort of service could be a viable candidate, such as a program that does some very complex calculations based on a specific set of input, or a program that regularly collects information from various web sites, consolidates that, and produces a new set of information based on what it found and makes that available to clients. Another example might be a dedicated encryption/decryption service, for communications security. To have a look at creating a server program, see Chapter 10, Server Programs.