The Apache HTTP Server, commonly referred to as Apache , is web server software outstanding for the purpose playing a pivotal duty in the initial development of the World Sizeable Web. In 2009 it became the principal cobweb server software to outshine the 100 million website milestone. Apache was the beginning rapport alternative to the Netscape Communications Corporation trap server (currently known as Message iPlanet Network Server), and has since evolved to challenge other snare servers in terms of functionality and performance. Typically Apache is run on a Unix-like operating system.
Apache is developed and maintained during an public community of developers underneath the sanction of the Apache Software Foundation. The utilization is elbow representing a wide selection 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 Allow, Apache is open-source software.
Since April 1996 Apache has been the most conventional 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, many implemented as compiled modules which on the pit functionality. These can latitude from server-side programming language authenticate to authentication schemes. Some conventional jargon interfaces buttress Perl, Python, Tcl, and PHP. Favoured authentication modules take in mod_access, mod_auth, mod_survive, and mod_auth_r‚sum‚, the successor to mod_digest. A illustration of other features include SSL and TLS support (mod_ssl), a representative module (mod_agent), a URL rewriter (also known as a rewrite appliance, implemented high mod_rewrite), custom log files (mod_log_config), and filtering reinforce (mod_register and mod_ext_screen).
Popular compression methods on Apache allow for the exotic augmentation module, mod_gzip, implemented to servants with reduction of the appraise (strain) of entanglement pages served during the course of HTTP. ModSecurity is an uncommitted rise intrusion detection and prevention machine in the direction of cobweb applications. Apache logs can be analyzed in the course a snare browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Essential hosting allows united Apache investiture to one's duty uncountable divers physical websites. For model, one machine with one Apache consecration could simultaneously serve www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and content negotiation. It is also supported next to disparate graphical drug interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing contraption and supports FTP.

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Although the sheer cabal end of Apache is not to be the "fastest" entanglement server, Apache does entertain dispatch comparable to other "high-performance" trap servers. In lieu of of implementing a individual architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which allow Apache to hump it in a process-based, half-breed (function and filament) or event-hybrid set-up, to think twice meet the demands of each separate infrastructure. This implies that the choice of suitable MPM and the correct configuration is important. Where compromises in doing need to be made, the stratagem of Apache is to humble latency and augment throughput, appurtenant to to austerely handling more requests, consequently ensuring in concordance and reliable processing of requests within logical time-frames.
The Apache reading considered past the Apache Base as providing high-performance is the multi-threaded style which mixes the utilize consume of a handful processes and individual threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads have a lower outlay than processes), it does not match the performances of the event-based architecture provided away other servers, uncommonly when they procedure events with a variety of wage-earner threads.
This difference can be easily explained beside the aloft that one line per connection brings (as opposed to a four of wage-earner threads per CPU, each processing diverse interplay events). Each ease needs to maintain its own load, environment, and switching from joke thread to another is also an priceless task in search CPUs.