The Httpd Web Server, commonly referred to as Apache , is web server software notable for the purpose playing a key place in the incipient success of the Cosmos Extensive Web. In 2009 it became the beginning web server software to surpass the 100 million website milestone. Apache was the chief practicable alternative to the Netscape Communications Corporation cobweb server (currently known as Oracle iPlanet Web Server), and has since evolved to compete with other web servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained by an unspoken for community of developers underneath the sanction of the Apache Software Foundation. The utilization is readily obtainable on a fully 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 Allow, Apache is open-source software.
Since April 1996 Apache has been the most fashionable 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 mixture of features, many implemented as compiled modules which extend the pit functionality. These can choice from server-side programming language assist to authentication schemes. Some community lingua franca interfaces support Perl, Python, Tcl, and PHP. Favoured authentication modules include mod_access, mod_auth, mod_pr‚cis, and mod_auth_r‚sum‚, the successor to mod_digest. A representation of other features embrace SSL and TLS support (mod_ssl), a factor module (mod_substitute), a URL rewriter (also known as a rewrite appliance, implemented supervised mod_rewrite), wont log files (mod_log_config), and filtering reinforce (mod_contain and mod_ext_filter).
Stock compression methods on Apache allow for the foreign dimensions module, mod_gzip, implemented to servants with reduction of the scope (ballast) of entanglement pages served over HTTP. ModSecurity is an available source intrusion detection and prevention machine object of entanglement applications. Apache logs can be analyzed in the course a cobweb browser using free scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows everyone Apache consecration to help uncountable divers verifiable websites. Through despite model, joined machine with one Apache ordination could simultaneously favourable to www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable boob messages, DBMS-based authentication databases, and content negotiation. It is also supported by sundry graphical operator interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing tool and supports FTP.

Performance


This section does not cite any references or sources. Content cure enhance this fraction by adding citations to sure sources. Unsourced fabric may be challenged and removed. (October 2009)
Although the sheer develop object of Apache is not to be the "fastest" web server, Apache does take dispatch comparable to other "high-performance" network servers. As contrasted with of implementing a individual architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which permit Apache to run in a process-based, composite (modify and piece of yarn) or event-hybrid mode, to superior blend the demands of each particular infrastructure. This implies that the select of neutralize MPM and the traditional configuration is important. Where compromises in dispatch desperate straits to be made, the conceive of Apache is to belittle latency and advance throughput, dependent on to simply handling more requests, that reason ensuring accordant and honourable processing of requests within reasonable time-frames.
The Apache version considered not later than the Apache Foundation as providing high-performance is the multi-threaded version which mixes the manipulate of diverse processes and diverse threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads prepare a trim outlay than processes), it does not accord the performances of the event-based architecture provided away other servers, uncommonly when they procedure events with respective workman threads.
This difference can be smoothly explained on the overhead that identical thread per interrelationship brings (as opposed to a twosome of breadwinner threads per CPU, each processing numberless drag relatives events). Each squeeze through needs to contend its own chimney, habitat, and switching from inseparable thread to another is also an priceless assignment in compensation CPUs.