The Apache HTTP Server, commonly referred to as Apache , is cobweb server software matchless seeking playing a level role in the initial development of the Society Wide Web. In 2009 it became the first cobweb server software to pass beyond the 100 million website milestone. Apache was the first rapport different to the Netscape Communications Corporation network server (currently known as Message iPlanet Web Server), and has since evolved to rival other trap 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 second to the approval of the Apache Software Foundation. The germaneness is ready instead of a deviating multiplicity 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 accommodate 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, divers implemented as compiled modules which on the pit functionality. These can class from server-side programming lingo authenticate to authentication schemes. Some inferior language interfaces guy Perl, Python, Tcl, and PHP. Trendy authentication modules include mod_access, mod_auth, mod_pr‚cis, and mod_auth_synopsis, the successor to mod_digest. A example of other features embrace SSL and TLS support (mod_ssl), a surrogate module (mod_agent), a URL rewriter (also known as a rewrite apparatus, implemented under mod_rewrite), to order log files (mod_log_config), and filtering sustain (mod_contain and mod_ext_filter).
Popular compression methods on Apache allow for the foreign height module, mod_gzip, implemented to improve with reduction of the area (strain) of entanglement pages served over HTTP. ModSecurity is an open begetter intrusion detection and interception apparatus object of web applications. Apache logs can be analyzed in the course a snare browser using free scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows one Apache investiture to serve multitudinous divers existent websites. On pattern, a specific machine with harmonious Apache ordination could simultaneously perform www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and content negotiation. It is also supported by disparate graphical user interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search locomotive and an HTML authorizing gimmick and supports FTP.

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Although the primary layout aspiration of Apache is not to be the "fastest" web server, Apache does take playing comparable to other "high-performance" web servers. As contrasted with of implementing a single architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which allow Apache to run in a process-based, combination (function and thread) or event-hybrid look, to excel blend 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 dispatch lack to be made, the design of Apache is to humble latency and augment throughput, associated to austerely handling more requests, consequently ensuring in concordance and reliable processing of requests within reasonable time-frames.
The Apache version considered past the Apache Foundation as providing high-performance is the multi-threaded translation which mixes the put to use of a handful processes and individual threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads suffer with a move running costs than processes), it does not match the performances of the event-based architecture provided sooner than other servers, uniquely when they process events with several wage-earner threads.
This inequality can be easily explained by the overhead that identical thread per connection brings (as opposed to a yoke of wage-earner threads per CPU, each processing numberless connection events). Each thread needs to keep going its own load, milieu, and switching from one plot to another is also an expensive task in search CPUs.