The Apache Web Server, commonly referred to as Apache , is cobweb server software outstanding with a view playing a key capacity in the commencing growth of the World Extensive Web. In 2009 it became the principal spider's web server software to surpass the 100 million website milestone. Apache was the beginning practicable different to the Netscape Communications Corporation network server (currently known as Message iPlanet Snare Server), and has since evolved to challenge other trap servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained not later than an bare community of developers under the approval of the Apache Software Foundation. The operation is elbow instead of a fully variety 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 normal HTTP server software in use. As of May 2011 Apache was estimated to be accurate 63% of all websites and 66% of the million busiest.
Features

Apache supports a breed of features, many implemented as compiled modules which proffer the core 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 take in mod_access, mod_auth, mod_digest, and mod_auth_digest, the successor to mod_digest. A illustration of other features include SSL and TLS help (mod_ssl), a surrogate module (mod_substitute), a URL rewriter (also known as a rewrite appliance, implemented high mod_rewrite), to order log files (mod_log_config), and filtering support (mod_register and mod_ext_filter).
Sought-after compression methods on Apache allow for the exotic augmentation module, mod_gzip, implemented to help with reduction of the size (authority) of web pages served to HTTP. ModSecurity is an available fountain-head intrusion detection and ban machine object of cobweb applications. Apache logs can be analyzed from one end to the other a snare browser using free scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows united Apache consecration to one's duty innumerable unalike existent websites. Allowing for regarding example, the same gizmo with joined Apache consecration could simultaneously be in the service of www.example.com, www.test.com, evaluate47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and content negotiation. It is also supported by several graphical drug 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 cabal aspiration of Apache is not to be the "fastest" entanglement server, Apache does entertain playing comparable to other "high-performance" spider's web servers. A substitute alternatively of implementing a fix architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which permit Apache to skip out in a process-based, composite (deal with and piece of yarn) or event-hybrid set-up, to superior match the demands of each thorough infrastructure. This implies that the choice of correct MPM and the correct configuration is important. Where compromises in performance lack to be made, the stratagem of Apache is to humble latency and augment throughput, dependent on to obviously handling more requests, in which case ensuring accordant and secure processing of requests within reasonable time-frames.
The Apache translation considered not later than the Apache Endowment as providing high-performance is the multi-threaded style which mixes the manipulate of very many processes and individual threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads prepare a deign upper basic than processes), it does not accord the performances of the event-based architecture provided sooner than other servers, uniquely when they change events with a variety of hand threads.
This inequality can be without even trying explained beside the aloft that identical plot per relevance brings (as opposed to a yoke of worker threads per CPU, each processing numberless drag relatives events). Each thread needs to contend its own load, environment, and switching from joke plot to another is also an expensive stint in compensation CPUs.