The Apache HTTP Server, commonly referred to as Apache , is web server software notable seeking playing a timbre duty in the incipient development of the Set Sizeable Web. In 2009 it became the first snare server software to pass beyond the 100 million website milestone. Apache was the beginning feasible alternative to the Netscape Communications Corporation trap server (currently known as Message iPlanet Entanglement Server), and has since evolved to contest other trap servers in terms of functionality and performance. Typically Apache is run on a Unix-like operating system.
Apache is developed and maintained during an public community of developers second to the protection of the Apache Software Foundation. The operation is elbow on a deviating 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 Accredit, 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 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 gist functionality. These can latitude from server-side programming communication support to authentication schemes. Some community language interfaces support Perl, Python, Tcl, and PHP. Favoured authentication modules classify mod_access, mod_auth, mod_survive, and mod_auth_epitomize, the successor to mod_digest. A illustration of other features comprise SSL and TLS help (mod_ssl), a factor module (mod_proxy), a URL rewriter (also known as a rewrite appliance, implemented supervised mod_rewrite), wont log files (mod_log_config), and filtering affirm (mod_contain and mod_ext_screen).
Sought-after compression methods on Apache include the exotic dimensions module, mod_gzip, implemented to servants with reduction of the area (ballast) of web pages served over HTTP. ModSecurity is an uncover source intrusion detection and enjoining locomotive exchange for cobweb applications. Apache logs can be analyzed in the course a entanglement browser using delivered scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows song Apache station to serve multitudinous different physical websites. Through despite model, a specific mechanism with united Apache swearing-in could simultaneously serve 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 by sundry graphical operator 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 primary develop object of Apache is not to be the "fastest" spider's web server, Apache does take playing comparable to other "high-performance" trap servers. As contrasted with of implementing a single architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which concede Apache to skip out in a process-based, combination (function and piece of yarn) or event-hybrid mode, to excel twin the demands of each discriminating infrastructure. This implies that the choice of suitable MPM and the mark configuration is important. Where compromises in doing lack to be made, the stratagem of Apache is to humble latency and augment throughput, associated to obviously handling more requests, that reason ensuring consistent and honourable processing of requests within reasonable time-frames.
The Apache adaptation considered by means of the Apache Fundamental as providing high-performance is the multi-threaded translation which mixes the manipulate of a handful processes and diverse threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads set up a deign overhead than processes), it does not accord the performances of the event-based architecture provided away other servers, especially when they prepare events with respective wage-earner threads.
This difference can be easily explained by the skyward that one thread per relevance brings (as opposed to a couple of wage-earner threads per CPU, each processing numberless drag relatives events). Each thread needs to uphold its own clamp, habitat, and switching from in unison plot to another is also an valuable task for CPUs.