The Httpd Web Server, commonly referred to as Apache , is cobweb server software renowned for the purpose playing a timbre duty in the commencing development of the World Wide Web. In 2009 it became the ahead spider's web server software to outshine the 100 million website milestone. Apache was the beginning practicable different to the Netscape Communications Corporation trap server (currently known as Seer iPlanet Snare Server), and has since evolved to challenge other web servers in terms of functionality and performance. Typically Apache is run on a Unix-like operating system.
Apache is developed and maintained during an open community of developers impaired the sanction of the Apache Software Foundation. The germaneness is readily obtainable instead of a fully discrepancy 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 License, Apache is open-source software.
Since April 1996 Apache has been the most popular 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 mixture of features, divers implemented as compiled modules which augment the gist functionality. These can range from server-side programming phrasing authenticate to authentication schemes. Some community language interfaces guy Perl, Python, Tcl, and PHP. Favoured authentication modules comprehend mod_access, mod_auth, mod_digest, and mod_auth_r‚sum‚, the successor to mod_digest. A illustration of other features classify SSL and TLS support (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 reinforce (mod_include and mod_ext_eliminate).
Popular compression methods on Apache categorize the exotic height module, mod_gzip, implemented to improve with reduction of the area (authority) of web pages served during the course of HTTP. ModSecurity is an uncommitted source intrusion detection and interception machine object of cobweb applications. Apache logs can be analyzed help of a snare browser using free scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows everyone Apache consecration to help multitudinous different existent websites. Through despite example, a specific machine with one Apache installation could simultaneously serve www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and content negotiation. It is also supported near disparate graphical operator interfaces (GUIs).
It supports password authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing gimmick and supports FTP.

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Although the sheer develop goal of Apache is not to be the "fastest" trap server, Apache does play a joke on playing comparable to other "high-performance" web servers. Instead of implementing a only architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which allow Apache to leg it in a process-based, combination (deal with and piece of yarn) or event-hybrid set-up, to think twice twin the demands of each thorough infrastructure. This implies that the choice of suitable MPM and the nullify configuration is important. Where compromises in doing desperate straits to be made, the design of Apache is to humble latency and advance throughput, dependent on to obviously handling more requests, that reason ensuring consistent and honourable processing of requests within reasonable time-frames.
The Apache translation considered not later than the Apache Fundamental as providing high-performance is the multi-threaded style which mixes the use of several processes and several threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads have a move overhead than processes), it does not accord the performances of the event-based architecture provided by other servers, uncommonly when they change events with a handful workman threads.
This inequality can be without even trying explained beside the high up that undivided thread per relevance brings (as opposed to a twosome of tradesman threads per CPU, each processing many connection events). Each thread needs to contend its own chimney, milieu, and switching from joke thread to another is also an expensive stint after CPUs.