The Apache Web Server, commonly referred to as Apache , is web server software notable for the purpose playing a key capacity in the introductory broadening of the Set Sizeable Web. In 2009 it became the first snare server software to outshine the 100 million website milestone. Apache was the beginning feasible different to the Netscape Communications Corporation trap server (currently known as Seer iPlanet Network Server), and has since evolved to compete with other entanglement 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 an unspoken for community of developers impaired the auspices of the Apache Software Foundation. The utilization is available for a wide selection 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 conventional 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 mixture of features, tons implemented as compiled modules which augment the core functionality. These can class from server-side programming language authenticate to authentication schemes. Some conventional jargon interfaces buttress Perl, Python, Tcl, and PHP. Favoured authentication modules comprehend mod_access, mod_auth, mod_grasp, and mod_auth_epitomize, the successor to mod_digest. A representation of other features classify SSL and TLS support (mod_ssl), a surrogate 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_comprehend and mod_ext_eliminate).
Sought-after compression methods on Apache allow for the foreign augmentation module, mod_gzip, implemented to help with reduction of the size (ballast) of snare pages served over HTTP. ModSecurity is an uncommitted source intrusion detection and enjoining engine for cobweb applications. Apache logs can be analyzed through a web browser using delivered scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows one Apache consecration to one's duty uncountable diverse physical websites. For benchmark, a specific mechanism with harmonious Apache consecration could simultaneously be in the service of www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable boob messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported by disparate graphical operator interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing contraption and supports FTP.

Performance


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Although the foremost design aspiration of Apache is not to be the "fastest" spider's web server, Apache does play a joke on performance comparable to other "high-performance" spider's web servers. A substitute alternatively of implementing a individual architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which concede Apache to leg it in a process-based, hybrid (deal with and filament) or event-hybrid set-up, to excel blend the demands of each separate infrastructure. This implies that the select of suitable MPM and the mark configuration is important. Where compromises in dispatch dire to be made, the design of Apache is to humble latency and advance throughput, dependent on to na‹vely handling more requests, thus ensuring accordant and secure processing of requests within logical time-frames.
The Apache reading considered by means of the Apache Endowment as providing high-performance is the multi-threaded style which mixes the use of a handful processes and diverse threads per process.
While this architecture works faster than the previous multi-process based topology (because threads set up a deign outlay than processes), it does not compare with the performances of the event-based architecture provided sooner than other servers, unusually when they procedure events with several wage-earner threads.
This distinction can be easily explained by means of the overhead that undivided filament per union brings (as opposed to a yoke of wage-earner threads per CPU, each processing diverse correlation events). Each squeeze through needs to uphold its own chimney, milieu, and switching from inseparable theme to another is also an priceless assignment after CPUs.