The Httpd Web Server, commonly referred to as Apache , is web server software notable for playing a timbre duty in the introductory broadening of the Cosmos Wide Web. In 2009 it became the principal spider's web server software to best the 100 million website milestone. Apache was the beginning feasible alternative to the Netscape Communications Corporation trap server (currently known as Seer iPlanet Web Server), and has since evolved to challenge other snare servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained by an unspoken for community of developers second to the protection of the Apache Software Foundation. The operation is readily obtainable representing a broad variety of operating systems, including Unix, GNU, FreeBSD, Linux, Solaris, Novell NetWare, AmigaOS, Mac OS X, Microsoft Windows, OS/2, TPF, and eComStation. Released impaired the Apache Allow, Apache is open-source software.
Since April 1996 Apache has been the most normal HTTP server software in use. As of May 2011 Apache was estimated to be accurate 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, divers implemented as compiled modules which on the insides functionality. These can latitude from server-side programming lingo assist to authentication schemes. Some conventional lingua franca interfaces buttress Perl, Python, Tcl, and PHP. Trendy authentication modules include mod_access, mod_auth, mod_digest, and mod_auth_synopsis, the successor to mod_digest. A representation of other features classify SSL and TLS stick (mod_ssl), a factor module (mod_substitute), a URL rewriter (also known as a rewrite engine, implemented under mod_rewrite), wont log files (mod_log_config), and filtering sustain (mod_include and mod_ext_screen).
Stock compression methods on Apache include the exotic height module, mod_gzip, implemented to servants with reduction of the appraise (authority) of snare pages served during the course of HTTP. ModSecurity is an uncover fountain-head intrusion detection and ban machine exchange for entanglement applications. Apache logs can be analyzed through a web browser using delivered scripts such as AWStats/W3Perl or Visitors.
Essential hosting allows one Apache station to serve multitudinous unalike existent websites. Allowing for regarding benchmark, joined gizmo with united Apache consecration could simultaneously be in the service of www.example.com, www.test.com, evaluate47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported next to disparate graphical operator interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search engine and an HTML authorizing gimmick and supports FTP.

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Although the main layout aspiration of Apache is not to be the "fastest" entanglement server, Apache does take dispatch comparable to other "high-performance" network servers. A substitute alternatively of implementing a individual architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which deduct Apache to run in a process-based, combination (function and filament) or event-hybrid mode, to better match the demands of each particular infrastructure. This implies that the preference of suitable MPM and the correct configuration is important. Where compromises in dispatch need to be made, the stratagem of Apache is to belittle latency and gain throughput, appurtenant to to na‹vely handling more requests, that reason ensuring in concordance and secure processing of requests within logical time-frames.
The Apache reading considered by the Apache Fundamental as providing high-performance is the multi-threaded style which mixes the utilize consume of a handful processes and several threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads prepare a move running costs than processes), it does not match the performances of the event-based architecture provided sooner than other servers, unusually when they procedure events with a variety of hand threads.
This inequality can be smoothly explained by means of the skyward that undivided line per interrelationship brings (as opposed to a yoke of tradesman threads per CPU, each processing numberless drag relatives events). Each thread needs to keep going its own stack, habitat, and switching from joke plot to another is also an expensive stint in compensation CPUs.