The Apache Web Server, commonly referred to as Apache , is cobweb server software matchless for the purpose playing a level capacity in the commencing development of the Society Extensive Web. In 2009 it became the principal web server software to best the 100 million website milestone. Apache was the first viable possibility to the Netscape Communications Corporation cobweb server (currently known as Message iPlanet Network Server), and has since evolved to challenge other web servers in terms of functionality and performance. Typically Apache is escape on a Unix-like operating system.
Apache is developed and maintained during an bare community of developers second to the approval of the Apache Software Foundation. The germaneness is elbow representing a wide 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 License, 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 collection of features, divers implemented as compiled modules which augment the insides functionality. These can latitude from server-side programming phrasing assist to authentication schemes. Some conventional words interfaces buttress Perl, Python, Tcl, and PHP. In demand authentication modules comprehend mod_access, mod_auth, mod_pr‚cis, and mod_auth_r‚sum‚, the successor to mod_digest. A representation of other features comprise SSL and TLS stick (mod_ssl), a factor module (mod_agent), a URL rewriter (also known as a rewrite appliance, implemented high mod_rewrite), routine log files (mod_log_config), and filtering affirm (mod_register and mod_ext_eliminate).
Popular compression methods on Apache categorize the foreign dimensions module, mod_gzip, implemented to ease with reduction of the area (ballast) of web pages served to HTTP. ModSecurity is an uncover fountain-head intrusion detection and enjoining engine object of cobweb applications. Apache logs can be analyzed through a snare browser using free scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows one Apache station to serve many unalike verifiable websites. Allowing for regarding example, a specific mechanism with one Apache consecration could simultaneously perform www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and content negotiation. It is also supported by several graphical user interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search locomotive and an HTML authorizing dupe and supports FTP.

Performance


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Although the sheer layout aspiration of Apache is not to be the "fastest" entanglement server, Apache does have dispatch comparable to other "high-performance" spider's web servers. Instead of implementing a fix architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which permit Apache to run in a process-based, half-breed (process and piece of yarn) or event-hybrid look, to think twice twin the demands of each particular infrastructure. This implies that the choice of neutralize MPM and the mark configuration is important. Where compromises in doing lack to be made, the design of Apache is to belittle latency and increase throughput, relative to obviously handling more requests, consequently ensuring in concordance and trusted processing of requests within reasonable time-frames.
The Apache adaptation considered by means of the Apache Foundation as providing high-performance is the multi-threaded version which mixes the put to use of diverse processes and diverse threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads suffer with a deign overhead than processes), it does not match the performances of the event-based architecture provided via other servers, unusually when they change events with a variety of wage-earner threads.
This difference can be without even trying explained on the aloft that a man line per connection brings (as opposed to a couple of wage-earner threads per CPU, each processing numberless interplay events). Each ease needs to contend its own clamp, environs, and switching from one thread to another is also an high-priced stint after CPUs.