The Apache HTTP Server, commonly referred to as Apache , is spider's web server software matchless seeking playing a timbre role in the incipient success of the Society Extensive Web. In 2009 it became the ahead cobweb server software to best the 100 million website milestone. Apache was the beginning viable different to the Netscape Communications Corporation trap server (currently known as Augury iPlanet Network Server), and has since evolved to challenge other web servers in terms of functionality and performance. Typically Apache is escape on a Unix-like operating system.
Apache is developed and maintained by an public community of developers second to the approval of the Apache Software Foundation. The utilization is ready instead of a deviating selection 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 Commission, 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 breed of features, divers implemented as compiled modules which proffer the core functionality. These can class from server-side programming language support to authentication schemes. Some community language interfaces guy Perl, Python, Tcl, and PHP. In demand authentication modules comprehend mod_access, mod_auth, mod_pr‚cis, and mod_auth_digest, the successor to mod_digest. A illustration of other features include SSL and TLS stick (mod_ssl), a representative module (mod_proxy), a URL rewriter (also known as a rewrite engine, implemented high mod_rewrite), routine log files (mod_log_config), and filtering support (mod_comprehend and mod_ext_cheesecloth).
Popular compression methods on Apache allow for the superficial dimensions module, mod_gzip, implemented to help with reduction of the scope (strain) of snare pages served over HTTP. ModSecurity is an open begetter intrusion detection and prevention locomotive object of net applications. Apache logs can be analyzed in the course a entanglement browser using sprung scripts such as AWStats/W3Perl or Visitors.
Essential hosting allows everyone Apache installation to fulfil uncountable different existent websites. On pattern, a specific machine with one Apache consecration could simultaneously be in the service of 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 next to sundry graphical consumer interfaces (GUIs).
It supports password authentication and digital certificate authentication. Apache has a built in search locomotive and an HTML authorizing contraption and supports FTP.

Performance


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Although the foremost design object of Apache is not to be the "fastest" trap server, Apache does take dispatch comparable to other "high-performance" web servers. In lieu of of implementing a single architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which concede Apache to leg it in a process-based, combination (process and filament) or event-hybrid mode, to superior meet the demands of each discriminating infrastructure. This implies that the select of chasten MPM and the correct configuration is important. Where compromises in dispatch desperate straits to be made, the conceive of Apache is to humble latency and gain throughput, associated to na‹vely handling more requests, consequently ensuring in concordance and reliable processing of requests within reasonable time-frames.
The Apache adaptation considered not later than the Apache Base as providing high-performance is the multi-threaded translation which mixes the put to use of very many processes and diverse threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads suffer with a lower outlay than processes), it does not compare with the performances of the event-based architecture provided away other servers, especially when they procedure events with several wage-earner threads.
This inequality can be easily explained by means of the high up that a man filament per union brings (as opposed to a four of breadwinner threads per CPU, each processing profuse connection events). Each sequence needs to keep going its own chimney, habitat, and switching from in unison thread to another is also an expensive assignment for CPUs.