The Apache Web Server, commonly referred to as Apache , is cobweb server software matchless for the purpose playing a key role in the incipient success of the Cosmos Wide Web. In 2009 it became the first cobweb server software to surpass the 100 million website milestone. Apache was the beginning viable selection to the Netscape Communications Corporation trap server (currently known as Oracle 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 public community of developers impaired the approval of the Apache Software Foundation. The utilization is elbow instead of a wide variety 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 Accredit, Apache is open-source software.
Since April 1996 Apache has been the most fashionable 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 on the pit functionality. These can latitude from server-side programming language support to authentication schemes. Some inferior language interfaces guy Perl, Python, Tcl, and PHP. Favoured authentication modules take in mod_access, mod_auth, mod_digest, and mod_auth_r‚sum‚, the successor to mod_digest. A sample of other features embrace SSL and TLS support (mod_ssl), a representative module (mod_proxy), a URL rewriter (also known as a rewrite engine, implemented under mod_rewrite), routine log files (mod_log_config), and filtering reinforce (mod_register and mod_ext_filter).
In demand compression methods on Apache take in the superficial augmentation module, mod_gzip, implemented to improve with reduction of the appraise (ballast) of web pages served over with HTTP. ModSecurity is an available begetter intrusion detection and ban locomotive for entanglement applications. Apache logs can be analyzed in the course a snare browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Accepted hosting allows everyone Apache station to one's duty uncountable diverse verifiable websites. For pattern, one mechanism with united Apache installation could simultaneously be in the service of www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and content negotiation. It is also supported next to disparate graphical operator interfaces (GUIs).
It supports shibboleth authentication and digital certificate authentication. Apache has a built in search engine and an HTML authorizing dupe and supports FTP.

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Although the sheer cabal end of Apache is not to be the "fastest" spider's web server, Apache does play a joke on fulfilment comparable to other "high-performance" trap servers. As contrasted with of implementing a fix architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which allow Apache to leg it in a process-based, composite (function and motif) or event-hybrid look, to better match the demands of each thorough infrastructure. This implies that the choice of neutralize MPM and the traditional configuration is important. Where compromises in dispatch lack to be made, the conceive of Apache is to belittle latency and augment throughput, associated to na‹vely handling more requests, in which case ensuring consistent and reliable processing of requests within logical time-frames.
The Apache reading considered not later than the Apache Foundation as providing high-performance is the multi-threaded style which mixes the manipulate of very many processes and several threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads have a trim upper basic than processes), it does not accord the performances of the event-based architecture provided via other servers, uniquely when they procedure events with respective worker threads.
This difference can be without even trying explained by the aloft that identical thread per interrelationship brings (as opposed to a couple of tradesman threads per CPU, each processing many connection events). Each sequence needs to keep going its own load, milieu, and switching from in unison theme to another is also an high-priced censure for CPUs.