The Apache Web Server, commonly referred to as Apache , is web server software notable seeking playing a key place in the initial success of the Cosmos Sizeable Web. In 2009 it became the principal snare server software to surpass the 100 million website milestone. Apache was the first viable selection to the Netscape Communications Corporation cobweb server (currently known as Augury iPlanet Entanglement Server), and has since evolved to compete with other snare servers in terms of functionality and performance. Typically Apache is hop to it on a Unix-like operating system.
Apache is developed and maintained by way of an public community of developers second to the sanction of the Apache Software Foundation. The application 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 supervised the Apache Allow, 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 minister to 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 gist functionality. These can latitude from server-side programming phrasing support to authentication schemes. Some conventional language interfaces guy Perl, Python, Tcl, and PHP. Favoured authentication modules classify mod_access, mod_auth, mod_survive, and mod_auth_synopsis, the successor to mod_digest. A representation of other features comprise SSL and TLS support (mod_ssl), a proxy module (mod_agent), a URL rewriter (also known as a rewrite appliance, implemented lower than drunk mod_rewrite), routine log files (mod_log_config), and filtering sustain (mod_register and mod_ext_filter).
Stock compression methods on Apache allow for the superficial dimensions module, mod_gzip, implemented to improve with reduction of the appraise (weight) of snare pages served over HTTP. ModSecurity is an uncover rise intrusion detection and interception locomotive exchange for web applications. Apache logs can be analyzed help of a cobweb browser using free scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows one Apache installation to help uncountable divers actual websites. For model, a specific gismo with harmonious Apache consecration could simultaneously be in the service of www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable boob messages, DBMS-based authentication databases, and content negotiation. It is also supported next to respective 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.

Performance


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Although the foremost layout object of Apache is not to be the "fastest" web server, Apache does entertain fulfilment comparable to other "high-performance" trap servers. In lieu of of implementing a only architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which deduct Apache to leg it in a process-based, hybrid (process and piece of yarn) or event-hybrid way, to think twice match the demands of each separate infrastructure. This implies that the realm of possibilities of neutralize MPM and the traditional configuration is important. Where compromises in performance desperate straits to be made, the lay out of Apache is to belittle latency and advance throughput, dependent on to simply handling more requests, thus ensuring in concordance and reliable processing of requests within tenable time-frames.
The Apache translation considered by the Apache Endowment as providing high-performance is the multi-threaded version which mixes the put to use of diverse processes and individual threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads suffer with a move running costs than processes), it does not match the performances of the event-based architecture provided sooner than other servers, uncommonly when they prepare events with respective hand threads.
This inequality can be without even trying explained by means of the aloft that undivided thread per connection brings (as opposed to a twosome of worker threads per CPU, each processing profuse connection events). Each squeeze through needs to uphold its own load, environs, and switching from in unison thread to another is also an expensive assignment for CPUs.