The Apache Web Server, commonly referred to as Apache , is spider's web server software notable for playing a pivotal role in the introductory success of the Society Sizeable Web. In 2009 it became the ahead snare server software to pass beyond the 100 million website milestone. Apache was the chief feasible possibility to the Netscape Communications Corporation web server (currently known as Oracle iPlanet Network Server), and has since evolved to rival other snare servers in terms of functionality and performance. Typically Apache is escape on a Unix-like operating system.
Apache is developed and maintained by an unspoken for community of developers underneath the protection of the Apache Software Foundation. The application is ready 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 junior to the Apache License, 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 accommodate 63% of all websites and 66% of the million busiest.
Features

Apache supports a collection of features, tons implemented as compiled modules which augment the insides functionality. These can range from server-side programming lingo support to authentication schemes. Some common jargon interfaces support Perl, Python, Tcl, and PHP. In demand authentication modules classify mod_access, mod_auth, mod_pr‚cis, and mod_auth_r‚sum‚, the successor to mod_digest. A illustration of other features include SSL and TLS stick (mod_ssl), a representative module (mod_agent), a URL rewriter (also known as a rewrite engine, implemented under mod_rewrite), wont log files (mod_log_config), and filtering sustain (mod_contain and mod_ext_eliminate).
In demand compression methods on Apache take in the foreign augmentation module, mod_gzip, implemented to improve with reduction of the scope (weight) of web pages served over with HTTP. ModSecurity is an available rise intrusion detection and ban engine for cobweb applications. Apache logs can be analyzed from one end to the other a web browser using free scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows one Apache installation to one's duty uncountable different existent websites. For pattern, joined machine with joined Apache consecration could simultaneously serve www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and capacity negotiation. It is also supported next to disparate graphical operator interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search engine 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" trap server, Apache does play a joke on fulfilment comparable to other "high-performance" web servers. As contrasted with of implementing a individual architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which concede Apache to leg it in a process-based, combination (modify and thread) or event-hybrid look, to think twice blend the demands of each discriminating infrastructure. This implies that the choice of neutralize MPM and the traditional configuration is important. Where compromises in dispatch lack to be made, the conceive of Apache is to belittle latency and advance throughput, associated to simply handling more requests, thus ensuring in concordance and trusted processing of requests within judicious time-frames.
The Apache translation considered not later than the Apache Foundation as providing high-performance is the multi-threaded style which mixes the use of a handful processes and several threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads have a lower overhead than processes), it does not accord the performances of the event-based architecture provided sooner than other servers, uniquely when they prepare events with respective wage-earner threads.
This difference can be beyond explained by the skyward that one thread per interrelationship brings (as opposed to a couple of tradesman threads per CPU, each processing profuse interplay events). Each squeeze through needs to contend its own clamp, milieu, and switching from inseparable theme to another is also an high-priced censure for CPUs.