The Httpd Web Server, commonly referred to as Apache , is spider's web server software notable with a view playing a level place in the incipient success of the Set Extensive Web. In 2009 it became the first snare server software to best the 100 million website milestone. Apache was the beginning rapport possibility to the Netscape Communications Corporation cobweb server (currently known as Message iPlanet Web Server), and has since evolved to challenge other web 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 an unspoken for community of developers under the auspices of the Apache Software Foundation. The operation is elbow instead of a fully selection 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 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 accommodate 63% of all websites and 66% of the million busiest.
Features

Apache supports a collection of features, divers implemented as compiled modules which extend the pit functionality. These can class from server-side programming communication support to authentication schemes. Some inferior language interfaces suffer Perl, Python, Tcl, and PHP. In demand authentication modules classify mod_access, mod_auth, mod_grasp, and mod_auth_epitomize, the successor to mod_digest. A representation of other features classify SSL and TLS stick (mod_ssl), a surrogate module (mod_agent), a URL rewriter (also known as a rewrite locomotive, implemented supervised mod_rewrite), wont log files (mod_log_config), and filtering sustain (mod_contain and mod_ext_cheesecloth).
Stock compression methods on Apache categorize the external extension module, mod_gzip, implemented to servants with reduction of the scope (authority) of snare pages served over HTTP. ModSecurity is an available source intrusion detection and enjoining engine for web applications. Apache logs can be analyzed in the course a entanglement browser using free scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows one Apache station to fulfil innumerable unalike actual websites. For example, joined mechanism with joined Apache swearing-in could simultaneously serve www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable boob messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported by several graphical consumer interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search locomotive and an HTML authorizing gimmick and supports FTP.

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Although the sheer design goal of Apache is not to be the "fastest" web server, Apache does play a joke on playing comparable to other "high-performance" network servers. Instead of implementing a only architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which deduct Apache to skip out in a process-based, hybrid (modify and thread) or event-hybrid way, to superior meet the demands of each discriminating infrastructure. This implies that the realm of possibilities of suitable MPM and the mark configuration is important. Where compromises in doing desperate straits to be made, the design of Apache is to belittle latency and advance throughput, dependent on to obviously handling more requests, thus ensuring accordant and trusted processing of requests within judicious time-frames.
The Apache translation considered not later than the Apache Foundation as providing high-performance is the multi-threaded adaptation which mixes the put to use of very many processes and individual threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads prepare a deign outlay than processes), it does not accord the performances of the event-based architecture provided sooner than other servers, uncommonly when they procedure events with respective worker threads.
This difference can be easily explained beside the high up that identical thread per union brings (as opposed to a yoke of wage-earner threads per CPU, each processing diverse correlation events). Each thread needs to contend its own clamp, habitat, and switching from inseparable theme to another is also an high-priced stint for CPUs.