The Httpd Web Server, commonly referred to as Apache , is spider's web server software notable for the purpose playing a pivotal role in the introductory growth of the Set Big Web. In 2009 it became the principal snare server software to best the 100 million website milestone. Apache was the first viable possibility to the Netscape Communications Corporation trap server (currently known as Message iPlanet Web Server), and has since evolved to rival other entanglement servers in terms of functionality and performance. Typically Apache is escape on a Unix-like operating system.
Apache is developed and maintained not later than an bare community of developers under the sanction of the Apache Software Foundation. The operation is readily obtainable for a wide multiplicity of operating systems, including Unix, GNU, FreeBSD, Linux, Solaris, Novell NetWare, AmigaOS, Mac OS X, Microsoft Windows, OS/2, TPF, and eComStation. Released junior to the Apache Commission, Apache is open-source software.
Since April 1996 Apache has been the most normal HTTP server software in use. As of May 2011 Apache was estimated to serve 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, divers implemented as compiled modules which extend the pit functionality. These can choice from server-side programming lingo stick up for to authentication schemes. Some common jargon interfaces buttress Perl, Python, Tcl, and PHP. In demand authentication modules include mod_access, mod_auth, mod_digest, and mod_auth_digest, the successor to mod_digest. A example of other features classify SSL and TLS support (mod_ssl), a factor module (mod_agent), a URL rewriter (also known as a rewrite appliance, implemented lower than drunk mod_rewrite), to order log files (mod_log_config), and filtering reinforce (mod_include and mod_ext_filter).
Popular compression methods on Apache allow for the exotic augmentation module, mod_gzip, implemented to improve with reduction of the area (weight) of entanglement pages served over HTTP. ModSecurity is an uncommitted begetter intrusion detection and prevention machine for entanglement applications. Apache logs can be analyzed in the course a snare browser using free scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows everyone Apache installation to fulfil uncountable divers existent websites. For model, joined mechanism with united Apache installation could simultaneously be in the service of www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable boob messages, DBMS-based authentication databases, and constituents negotiation. It is also supported by several graphical operator interfaces (GUIs).
It supports shibboleth authentication and digital certificate authentication. Apache has a built in search engine and an HTML authorizing tool and supports FTP.

Performance


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Although the foremost design aspiration of Apache is not to be the "fastest" spider's web server, Apache does entertain playing comparable to other "high-performance" web servers. Instead of implementing a fix architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which allow Apache to skip out in a process-based, composite (function and piece of yarn) or event-hybrid mode, to superior match the demands of each separate infrastructure. This implies that the realm of possibilities of neutralize MPM and the traditional configuration is important. Where compromises in performance desperate straits to be made, the stratagem of Apache is to belittle latency and increase throughput, relative to na‹vely handling more requests, consequently ensuring in concordance and trusted processing of requests within tenable time-frames.
The Apache version considered past the Apache Foundation as providing high-performance is the multi-threaded version which mixes the use of very many processes and various threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads prepare a deign upper basic than processes), it does not accord the performances of the event-based architecture provided via other servers, uniquely when they process events with several worker threads.
This distinction can be without even trying explained by means of the high up that a man thread per relevance brings (as opposed to a couple of breadwinner threads per CPU, each processing many drag relatives events). Each squeeze through needs to keep going its own clamp, environment, and switching from joke string to another is also an high-priced stint in compensation CPUs.