The Httpd Web Server, commonly referred to as Apache , is web server software matchless for the purpose playing a level duty in the incipient success of the World Sizeable Web. In 2009 it became the principal snare server software to best the 100 million website milestone. Apache was the first viable possibility to the Netscape Communications Corporation trap server (currently known as Seer iPlanet Entanglement Server), and has since evolved to challenge other entanglement servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained during an public community of developers under the approval of the Apache Software Foundation. The application is available for a wide discrepancy of operating systems, including Unix, GNU, FreeBSD, Linux, Solaris, Novell NetWare, AmigaOS, Mac OS X, Microsoft Windows, OS/2, TPF, and eComStation. Released under the Apache License, Apache is open-source software.
Since April 1996 Apache has been the most popular HTTP server software in use. As of May 2011 Apache was estimated to serve 63% of all websites and 66% of the million busiest.
Features

Apache supports a collection of features, varied implemented as compiled modules which extend the gist functionality. These can latitude from server-side programming language support to authentication schemes. Some inferior lingua franca interfaces support Perl, Python, Tcl, and PHP. Trendy authentication modules include mod_access, mod_auth, mod_digest, and mod_auth_digest, the successor to mod_digest. A illustration of other features include SSL and TLS support (mod_ssl), a representative module (mod_substitute), a URL rewriter (also known as a rewrite appliance, implemented lower than drunk mod_rewrite), wont log files (mod_log_config), and filtering sustain (mod_contain and mod_ext_screen).
Sought-after compression methods on Apache take in the foreign augmentation module, mod_gzip, implemented to ease with reduction of the scope (ballast) of cobweb pages served over HTTP. ModSecurity is an available source intrusion detection and interception apparatus object of entanglement applications. Apache logs can be analyzed in the course a snare browser using sprung scripts such as AWStats/W3Perl or Visitors.
Essential hosting allows one Apache installation to fulfil many divers verifiable websites. On model, a specific gizmo with harmonious Apache consecration could simultaneously perform www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and capacity negotiation. It is also supported not later than several graphical drug interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing tool and supports FTP.

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Although the primary develop end of Apache is not to be the "fastest" spider's web server, Apache does take playing comparable to other "high-performance" spider's web servers. Instead of implementing a fix architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which concede Apache to hump it in a process-based, composite (modify and filament) or event-hybrid set-up, to excel twin the demands of each separate infrastructure. This implies that the preference of suitable MPM and the nullify configuration is important. Where compromises in doing dire to be made, the stratagem of Apache is to belittle latency and increase throughput, appurtenant to to obviously handling more requests, thus ensuring consistent and trusted processing of requests within tenable time-frames.
The Apache reading considered by the Apache Fundamental as providing high-performance is the multi-threaded adaptation which mixes the manipulate of several processes and individual threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads set up a move upper basic than processes), it does not copy the performances of the event-based architecture provided via other servers, especially when they change events with a handful hand threads.
This distinction can be easily explained beside the skyward that undivided line per connection brings (as opposed to a yoke of tradesman threads per CPU, each processing diverse interplay events). Each squeeze through needs to uphold its own clamp, milieu, and switching from in unison plot to another is also an expensive assignment in compensation CPUs.