The History and Popularity of Apache

The Apache Project was launched in 1995 when a development team began applying software “patches” to the source code of the NCSA httpd web server. NCSA httpd, developed at the National Center for Supercomputing Applications at the University of Illinois, was one of the first web servers developed. This web server was wedded to the first popular web browser, NCSA Mosaic. However, development of NCSA httpd stalled in 1994, when Rob McCool, the lead developer, left to work for Netscape. At Netscape, McCool worked on the development of the Netscape Enterprise Server, another web server that in the late 1990s played an important role in the development of the modern web, along with the Netscape web browser.

The patches to Apache led to a fork of the NCSA httpd software. Because of the many patches to NCSA httpd that led to Apache, it is often quipped that the name “Apache” came from the fact that it was “a patchy” httpd. Apache has been an open-source project, free of licensing costs, from its start. The source code of Apache was made available on the Internet to encourage others to download it, use it, and contribute improvements. Within a year of its inception, a survey showed that Apache had become the most popular web server. Other surveys showed that by 1999 close to 60 percent of all web sites were running Apache, and in early 2006, close to 70 percent of all web sites were running Apache.

During its swift rise to the status of the most popular web server, Apache ran almost exclusively on UNIX and Linux systems. The older version 1.3 and newer 2.x branches of Apache are now install-time options on every major Linux distribution and open-source BSD variants such as FreeBSD. The major UNIX variants almost all bundle some version of Apache. Apache is a part of the Solaris “Freeware” installation option. IBM AIX includes the IBM HTTP Server, which is based on Apache. HP-UX includes an “Apache-Based Web Server Suite.” The 2.x branch of Apache, which was written from scratch to be free of any remaining vestiges of NCSA httpd code, has become a popular choice for web server on even Microsoft Windows server operating systems. However, all branches of Apache still reflect the UNIX heritage in their configuration system. For example, Apache is configured through plain text configuration files. As Apache has grown in its feature set to keep pace with the growing demands and innovations of the web, the configuration of Apache has also become increasingly complex. Luckily, as with most successful software projects, a sensible default configuration is included so that web sites using Apache can be built fairly quickly There are also graphical user interface (GUI) or web front ends designed to tame the complexity of Apache’s many configuration options. This chapter will discuss basic Apache configuration.