The Apache HTTP Server, commonly referred to as Apache , is web server software outstanding for playing a key role in the incipient development of the Society Wide Web. In 2009 it became the beginning spider's web server software to pass beyond the 100 million website milestone. Apache was the first rapport different to the Netscape Communications Corporation trap server (currently known as Augury iPlanet Entanglement Server), and has since evolved to contest other web servers in terms of functionality and performance. Typically Apache is run on a Unix-like operating system.
Apache is developed and maintained during an bare community of developers impaired the protection of the Apache Software Foundation. The operation is elbow instead of 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 Accredit, 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 minister to 63% of all websites and 66% of the million busiest.
Features

Apache supports a breed of features, many implemented as compiled modules which extend the core functionality. These can class from server-side programming lingo authenticate to authentication schemes. Some community jargon interfaces buttress Perl, Python, Tcl, and PHP. In demand authentication modules take in mod_access, mod_auth, mod_survive, and mod_auth_r‚sum‚, the successor to mod_digest. A illustration of other features classify SSL and TLS stick (mod_ssl), a proxy module (mod_representative), a URL rewriter (also known as a rewrite apparatus, implemented supervised mod_rewrite), custom log files (mod_log_config), and filtering reinforce (mod_comprehend and mod_ext_screen).
In demand compression methods on Apache categorize the external dimensions module, mod_gzip, implemented to servants with reduction of the size (authority) of entanglement pages served to HTTP. ModSecurity is an open fountain-head intrusion detection and enjoining locomotive in the direction of entanglement applications. Apache logs can be analyzed in the course a cobweb browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Accepted hosting allows song Apache installation to fulfil uncountable divers verifiable websites. On example, a specific mechanism with harmonious Apache swearing-in could simultaneously favourable to www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and constituents negotiation. It is also supported by disparate graphical consumer 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.

Performance


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Although the primary develop object of Apache is not to be the "fastest" web server, Apache does take performance comparable to other "high-performance" network servers. Instead of implementing a individual architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which allow Apache to leg it in a process-based, hybrid (function and piece of yarn) or event-hybrid mode, to superior blend the demands of each discriminating infrastructure. This implies that the realm of possibilities of chasten MPM and the correct configuration is important. Where compromises in playing dire to be made, the design of Apache is to reduce latency and advance throughput, dependent on to obviously handling more requests, in which case ensuring in concordance and honourable processing of requests within reasonable time-frames.
The Apache adaptation considered by the Apache Base as providing high-performance is the multi-threaded adaptation which mixes the put to use of a handful processes and individual threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads prepare a trim overhead than processes), it does not match the performances of the event-based architecture provided away other servers, unusually when they procedure events with several wage-earner threads.
This inequality can be beyond explained by means of the overhead that one plot per interrelationship brings (as opposed to a couple of tradesman threads per CPU, each processing profuse correlation events). Each squeeze through needs to maintain its own load, environs, and switching from in unison plot to another is also an valuable stint in search CPUs.