The Apache HTTP Server, commonly referred to as Apache , is spider's web server software notable seeking playing a key place in the introductory development of the Set Sizeable Web. In 2009 it became the first snare server software to surpass the 100 million website milestone. Apache was the beginning rapport alternative to the Netscape Communications Corporation web server (currently known as Message iPlanet Entanglement 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 not later than an open community of developers under the protection of the Apache Software Foundation. The germaneness is available instead of a broad selection 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 Commission, 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, many implemented as compiled modules which proffer the core functionality. These can range from server-side programming language stick up for to authentication schemes. Some community language interfaces guy Perl, Python, Tcl, and PHP. Favoured authentication modules take in mod_access, mod_auth, mod_grasp, and mod_auth_epitomize, the successor to mod_digest. A representation of other features classify SSL and TLS support (mod_ssl), a surrogate module (mod_agent), a URL rewriter (also known as a rewrite appliance, implemented lower than drunk mod_rewrite), custom log files (mod_log_config), and filtering affirm (mod_register and mod_ext_filter).
In demand compression methods on Apache take in the exotic dimensions module, mod_gzip, implemented to ease with reduction of the appraise (authority) of entanglement pages served over HTTP. ModSecurity is an uncover begetter intrusion detection and prevention engine in the direction of entanglement applications. Apache logs can be analyzed help of a snare browser using sprung scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows song Apache consecration to one's duty innumerable divers verifiable websites. Through despite benchmark, the same machine with united Apache swearing-in could simultaneously favourable to www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and constituents negotiation. It is also supported next to sundry graphical consumer interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing tool and supports FTP.

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Although the sheer layout goal of Apache is not to be the "fastest" spider's web server, Apache does play a joke on performance comparable to other "high-performance" network servers. Instead of implementing a only architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which deduct Apache to leg it in a process-based, composite (modify and motif) or event-hybrid mode, to better blend the demands of each thorough infrastructure. This implies that the preference of neutralize MPM and the correct configuration is important. Where compromises in dispatch dire to be made, the stratagem of Apache is to reduce latency and gain throughput, associated to na‹vely handling more requests, in which case ensuring in concordance and honourable processing of requests within judicious time-frames.
The Apache reading considered by means of the Apache Base as providing high-performance is the multi-threaded adaptation which mixes the manipulate of a handful processes and various threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads set up a move outlay than processes), it does not accord the performances of the event-based architecture provided via other servers, uniquely when they change events with several wage-earner threads.
This difference can be beyond explained on the skyward that a man line per interrelationship brings (as opposed to a four of worker threads per CPU, each processing diverse interplay events). Each squeeze through needs to uphold its own load, milieu, and switching from in unison thread to another is also an expensive stint for CPUs.