The Httpd Web Server, commonly referred to as Apache , is cobweb server software outstanding with a view playing a pivotal place in the initial success of the World Extensive Web. In 2009 it became the ahead spider's web server software to best the 100 million website milestone. Apache was the beginning practicable different to the Netscape Communications Corporation trap server (currently known as Message iPlanet Network Server), and has since evolved to compete with other trap servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained by way of an public community of developers second to the auspices of the Apache Software Foundation. The germaneness is elbow on a broad discrepancy 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 Allow, 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 pit functionality. These can choice from server-side programming phrasing authenticate to authentication schemes. Some conventional language interfaces suffer Perl, Python, Tcl, and PHP. In demand authentication modules classify mod_access, mod_auth, mod_survive, and mod_auth_synopsis, the successor to mod_digest. A illustration of other features include SSL and TLS support (mod_ssl), a representative module (mod_agent), a URL rewriter (also known as a rewrite locomotive, implemented supervised mod_rewrite), to order log files (mod_log_config), and filtering affirm (mod_register and mod_ext_screen).
Stock compression methods on Apache allow for the external extension module, mod_gzip, implemented to help with reduction of the appraise (weight) of entanglement pages served to HTTP. ModSecurity is an uncover rise intrusion detection and enjoining locomotive object of web applications. Apache logs can be analyzed in the course a web browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Accepted hosting allows everyone Apache station to one's duty multitudinous unalike verifiable websites. Allowing for regarding benchmark, joined gismo with united Apache installation could simultaneously serve www.example.com, www.test.com, evaluate47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported next to respective graphical operator interfaces (GUIs).
It supports shibboleth authentication and digital certificate authentication. Apache has a built in search apparatus and an HTML authorizing contraption and supports FTP.

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Although the foremost develop goal of Apache is not to be the "fastest" entanglement server, Apache does entertain playing comparable to other "high-performance" web servers. Instead of implementing a fix architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which allow Apache to leg it in a process-based, half-breed (process and thread) or event-hybrid look, to superior match the demands of each separate infrastructure. This implies that the select of suitable MPM and the traditional configuration is important. Where compromises in performance dire to be made, the design of Apache is to humble latency and advance throughput, appurtenant to to austerely handling more requests, in which case ensuring consistent and secure processing of requests within tenable time-frames.
The Apache adaptation considered by the Apache Foundation as providing high-performance is the multi-threaded adaptation which mixes the manipulate of diverse processes and various threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads have a deign outlay than processes), it does not match the performances of the event-based architecture provided by other servers, uniquely when they process events with respective worker threads.
This dissimilarity can be smoothly explained on the high up that identical plot per relevance brings (as opposed to a couple of worker threads per CPU, each processing numberless connection events). Each sequence needs to keep going its own chimney, milieu, and switching from inseparable string to another is also an valuable stint after CPUs.