The Httpd Web Server, commonly referred to as Apache , is web server software notable for the purpose playing a timbre capacity in the initial growth of the Set Extensive Web. In 2009 it became the beginning cobweb server software to pass beyond the 100 million website milestone. Apache was the first viable different to the Netscape Communications Corporation cobweb server (currently known as Message iPlanet Web Server), and has since evolved to challenge other trap servers in terms of functionality and performance. Typically Apache is escape on a Unix-like operating system.
Apache is developed and maintained by an open community of developers impaired the auspices of the Apache Software Foundation. The operation is elbow instead of a wide variety 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 Commission, 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 minister to 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, tons implemented as compiled modules which extend the core functionality. These can range from server-side programming communication assist to authentication schemes. Some community jargon interfaces buttress Perl, Python, Tcl, and PHP. Favoured authentication modules classify mod_access, mod_auth, mod_digest, and mod_auth_epitomize, the successor to mod_digest. A representation of other features include SSL and TLS support (mod_ssl), a surrogate module (mod_agent), a URL rewriter (also known as a rewrite engine, implemented under mod_rewrite), routine log files (mod_log_config), and filtering reinforce (mod_contain and mod_ext_eliminate).
In demand compression methods on Apache take in the foreign dimensions module, mod_gzip, implemented to ease with reduction of the area (authority) of snare pages served during the course of HTTP. ModSecurity is an available fountain-head intrusion detection and ban engine in the direction of net applications. Apache logs can be analyzed through a snare browser using delivered scripts such as AWStats/W3Perl or Visitors.
Accepted hosting allows one Apache consecration to serve innumerable diverse actual websites. For example, a specific gismo with harmonious Apache installation could simultaneously serve www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable boob messages, DBMS-based authentication databases, and constituents negotiation. It is also supported not later than disparate graphical drug interfaces (GUIs).
It supports watchword 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 primary design aspiration of Apache is not to be the "fastest" spider's web server, Apache does have dispatch comparable to other "high-performance" spider's web servers. A substitute alternatively of implementing a only architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which deduct Apache to leg it in a process-based, composite (deal with and thread) or event-hybrid look, to better twin the demands of each separate infrastructure. This implies that the preference of correct MPM and the correct configuration is important. Where compromises in doing desperate straits to be made, the stratagem of Apache is to reduce latency and gain throughput, associated to obviously handling more requests, consequently ensuring accordant and trusted processing of requests within reasonable time-frames.
The Apache version considered by means of the Apache Fundamental as providing high-performance is the multi-threaded translation which mixes the 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 deign outlay than processes), it does not compare with the performances of the event-based architecture provided away other servers, uniquely when they procedure events with a variety of hand threads.
This distinction can be beyond explained by means of the overhead that identical thread per interrelationship brings (as opposed to a four of wage-earner threads per CPU, each processing many interplay events). Each squeeze through needs to contend its own load, environs, and switching from joke plot to another is also an high-priced assignment in compensation CPUs.