The Apache HTTP server, maintained by the Apache Software Foundation, is currently the most popular Web server because of its stability, cost, efficiency and portability. It is an open-source software (i.e., its source code is freely available) that runs on UNIX, Linux and Windows platforms.
To download the Apache HTTP server, visit httpd.apache.org. For instructions on installing Apache, visit www.deitel.com or httpd.apache.org. If the Apache HTTP server is installed as a service, then it is already running after installation. Otherwise, start the server by selecting the Start menu, then All Programs > Apache HTTP Server 2.0.52 > Control Apache Server > Start. To stop the Apache HTTP server, select Start > All Programs > Apache HTTP Server 2.0.52 > Control Apache Server > Stop. For Linux users, we put instructions on how to start/stop the Apache HTTP server and run the examples at our Web site, www.deitel.com.
 In this chapter, we use version 2.0.52.