The Httpd Web Server, commonly referred to as Apache , is cobweb server software notable for the purpose playing a timbre duty in the commencing broadening of the World Sizeable Web. In 2009 it became the principal web server software to best the 100 million website milestone. Apache was the beginning rapport alternative to the Netscape Communications Corporation web server (currently known as Seer iPlanet Network Server), and has since evolved to challenge other web 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 bare community of developers under the sanction of the Apache Software Foundation. The operation is available on a fully variety 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 conventional 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 extend the insides functionality. These can range from server-side programming language support to authentication schemes. Some conventional words interfaces buttress Perl, Python, Tcl, and PHP. Favoured authentication modules comprehend mod_access, mod_auth, mod_grasp, and mod_auth_digest, the successor to mod_digest. A illustration of other features include SSL and TLS help (mod_ssl), a proxy module (mod_proxy), a URL rewriter (also known as a rewrite appliance, implemented high mod_rewrite), wont log files (mod_log_config), and filtering reinforce (mod_contain and mod_ext_filter).
Popular compression methods on Apache take in the external height module, mod_gzip, implemented to servants with reduction of the area (ballast) of snare pages served during the course of HTTP. ModSecurity is an uncommitted rise intrusion detection and prevention apparatus exchange for cobweb applications. Apache logs can be analyzed help of a snare browser using delivered scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows one Apache station to serve uncountable unalike physical websites. Through despite example, a specific machine with one Apache installation could simultaneously be in the service of www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and content negotiation. It is also supported near respective graphical operator interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search locomotive and an HTML authorizing contraption and supports FTP.

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Although the foremost layout end of Apache is not to be the "fastest" spider's web server, Apache does entertain playing comparable to other "high-performance" network servers. A substitute alternatively of implementing a fix architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which deduct Apache to skip out in a process-based, composite (modify and motif) or event-hybrid way, to excel meet the demands of each thorough infrastructure. This implies that the realm of possibilities of neutralize MPM and the mark configuration is important. Where compromises in performance lack to be made, the stratagem of Apache is to reduce latency and advance throughput, dependent on to simply handling more requests, consequently ensuring predictable and secure processing of requests within reasonable time-frames.
The Apache reading considered by means of the Apache Endowment as providing high-performance is the multi-threaded adaptation which mixes the manipulate of very many processes and individual threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads set up a lower running costs than processes), it does not match the performances of the event-based architecture provided via other servers, uncommonly when they procedure events with respective hand threads.
This dissimilarity can be without even trying explained beside the high up that a man thread per connection brings (as opposed to a yoke of worker threads per CPU, each processing numberless drag relatives events). Each sequence needs to contend its own stack, milieu, and switching from inseparable plot to another is also an high-priced task after CPUs.