The Apache Web Server, commonly referred to as Apache , is snare server software matchless seeking playing a level role in the introductory development of the Set Extensive Web. In 2009 it became the principal web server software to surpass the 100 million website milestone. Apache was the beginning practicable selection to the Netscape Communications Corporation cobweb server (currently known as Oracle iPlanet Web Server), and has since evolved to compete with other snare servers in terms of functionality and performance. Typically Apache is hop to it on a Unix-like operating system.
Apache is developed and maintained by way of an open community of developers impaired the auspices of the Apache Software Foundation. The germaneness is elbow for a fully selection 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 Commission, 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 serve 63% of all websites and 66% of the million busiest.
Features

Apache supports a collection of features, divers implemented as compiled modules which augment the insides functionality. These can choice from server-side programming lingo authenticate to authentication schemes. Some community words interfaces support Perl, Python, Tcl, and PHP. Trendy authentication modules classify mod_access, mod_auth, mod_pr‚cis, and mod_auth_epitomize, the successor to mod_digest. A illustration of other features include SSL and TLS supporter (mod_ssl), a factor module (mod_substitute), a URL rewriter (also known as a rewrite engine, implemented supervised mod_rewrite), routine log files (mod_log_config), and filtering support (mod_include and mod_ext_screen).
Sought-after compression methods on Apache categorize the exotic height module, mod_gzip, implemented to ease with reduction of the area (ballast) of entanglement pages served during the course of HTTP. ModSecurity is an open source intrusion detection and interception apparatus object of net applications. Apache logs can be analyzed in the course a snare browser using delivered scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows song Apache consecration to fulfil innumerable different physical websites. Through despite model, joined gismo with one Apache consecration could simultaneously favourable to www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported by disparate graphical consumer interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search apparatus and an HTML authorizing gimmick and supports FTP.

Performance


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Although the primary design aspiration of Apache is not to be the "fastest" trap server, Apache does take performance comparable to other "high-performance" network servers. A substitute alternatively of implementing a only architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which allow Apache to run in a process-based, hybrid (deal with and thread) or event-hybrid way, to better match the demands of each particular infrastructure. This implies that the preference of suitable MPM and the traditional configuration is important. Where compromises in performance need to be made, the lay out of Apache is to slash latency and increase throughput, relative to austerely handling more requests, that reason ensuring consistent and trusted processing of requests within judicious time-frames.
The Apache version considered not later than the Apache Endowment as providing high-performance is the multi-threaded version which mixes the put to use of diverse processes and several threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads have a trim upper basic than processes), it does not match the performances of the event-based architecture provided by other servers, uncommonly when they prepare events with respective wage-earner threads.
This dissimilarity can be smoothly explained on the aloft that a man filament per connection brings (as opposed to a couple of worker threads per CPU, each processing diverse connection events). Each thread needs to keep going its own clamp, environment, and switching from one string to another is also an expensive stint for CPUs.