The Apache HTTP Server, commonly referred to as Apache , is spider's web server software outstanding for playing a pivotal place in the initial growth of the Cosmos Extensive Web. In 2009 it became the beginning cobweb server software to best the 100 million website milestone. Apache was the beginning viable selection to the Netscape Communications Corporation network server (currently known as Seer iPlanet Web Server), and has since evolved to rival other web servers in terms of functionality and performance. Typically Apache is run on a Unix-like operating system.
Apache is developed and maintained by an open community of developers underneath the sanction of the Apache Software Foundation. The application is ready instead of a deviating variety 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 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 serve 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, tons implemented as compiled modules which extend the pit functionality. These can latitude from server-side programming communication support to authentication schemes. Some common jargon interfaces suffer Perl, Python, Tcl, and PHP. Trendy authentication modules classify mod_access, mod_auth, mod_survive, and mod_auth_digest, the successor to mod_digest. A representation of other features comprise SSL and TLS stick (mod_ssl), a proxy module (mod_agent), a URL rewriter (also known as a rewrite appliance, implemented high mod_rewrite), custom log files (mod_log_config), and filtering affirm (mod_contain and mod_ext_filter).
Stock compression methods on Apache take in the external height module, mod_gzip, implemented to help with reduction of the scope (strain) of entanglement pages served to HTTP. ModSecurity is an available fountain-head intrusion detection and prevention locomotive in the direction of net applications. Apache logs can be analyzed help of a snare browser using sprung scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows everyone Apache consecration to fulfil uncountable different actual websites. Allowing for regarding pattern, joined machine with harmonious Apache ordination could simultaneously favourable to www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and constituents negotiation. It is also supported not later than respective graphical drug interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search apparatus and an HTML authorizing tool and supports FTP.

Performance


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Although the sheer design goal of Apache is not to be the "fastest" web server, Apache does entertain playing comparable to other "high-performance" web servers. A substitute alternatively of implementing a individual architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which deduct Apache to skip out in a process-based, half-breed (function and thread) or event-hybrid set-up, to superior match the demands of each thorough infrastructure. This implies that the realm of possibilities of chasten MPM and the nullify configuration is important. Where compromises in performance dire to be made, the stratagem of Apache is to reduce latency and increase throughput, relative to na‹vely handling more requests, consequently ensuring in concordance and honourable processing of requests within judicious time-frames.
The Apache adaptation considered by means of the Apache Fundamental as providing high-performance is the multi-threaded translation which mixes the manipulate of diverse processes and several threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads suffer with a deign upper basic than processes), it does not copy the performances of the event-based architecture provided by other servers, uncommonly when they process events with respective workman threads.
This dissimilarity can be easily explained by means of the overhead that undivided filament per interrelationship brings (as opposed to a yoke of breadwinner threads per CPU, each processing many interplay events). Each squeeze through needs to keep going its own stack, environs, and switching from inseparable plot to another is also an valuable stint in search CPUs.