The Httpd Web Server, commonly referred to as Apache , is snare server software renowned with a view playing a key role in the incipient growth of the Cosmos Extensive Web. In 2009 it became the principal cobweb server software to best the 100 million website milestone. Apache was the beginning rapport possibility to the Netscape Communications Corporation network server (currently known as Seer iPlanet Network Server), and has since evolved to challenge other trap servers in terms of functionality and performance. Typically Apache is escape on a Unix-like operating system.
Apache is developed and maintained not later than an bare community of developers under the protection of the Apache Software Foundation. The application is elbow for a wide discrepancy 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 Accredit, 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 minister to 63% of all websites and 66% of the million busiest.
Features

Apache supports a breed of features, varied implemented as compiled modules which augment the pit functionality. These can class from server-side programming lingo stick up for to authentication schemes. Some conventional lingua franca interfaces guy Perl, Python, Tcl, and PHP. Favoured authentication modules comprehend mod_access, mod_auth, mod_survive, and mod_auth_epitomize, the successor to mod_digest. A representation of other features embrace SSL and TLS stick (mod_ssl), a proxy module (mod_proxy), a URL rewriter (also known as a rewrite apparatus, implemented lower than drunk mod_rewrite), wont log files (mod_log_config), and filtering sustain (mod_contain and mod_ext_eliminate).
Popular compression methods on Apache include the exotic extension module, mod_gzip, implemented to servants with reduction of the appraise (authority) of cobweb pages served over with HTTP. ModSecurity is an open begetter intrusion detection and prevention apparatus object of net applications. Apache logs can be analyzed help of a entanglement browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows song Apache station to fulfil many different physical websites. Through despite benchmark, joined gizmo with harmonious Apache consecration could simultaneously be in the service of www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and content negotiation. It is also supported next to disparate graphical user interfaces (GUIs).
It supports shibboleth 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 main layout aspiration of Apache is not to be the "fastest" entanglement server, Apache does entertain playing comparable to other "high-performance" web servers. In lieu of of implementing a individual architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which permit Apache to leg it in a process-based, half-breed (deal with and filament) or event-hybrid way, to think twice twin the demands of each discriminating infrastructure. This implies that the choice of chasten MPM and the nullify configuration is important. Where compromises in performance desperate straits to be made, the lay out of Apache is to reduce latency and increase throughput, dependent on to simply handling more requests, thus ensuring predictable and secure processing of requests within reasonable time-frames.
The Apache adaptation considered past the Apache Base as providing high-performance is the multi-threaded translation which mixes the utilize consume of diverse processes and diverse threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads set up a lower upper basic than processes), it does not copy the performances of the event-based architecture provided by other servers, uniquely when they change events with a variety of wage-earner threads.
This distinction can be beyond explained on the aloft that undivided filament per union brings (as opposed to a twosome of wage-earner threads per CPU, each processing diverse drag relatives events). Each thread needs to contend its own chimney, milieu, and switching from in unison string to another is also an high-priced task for CPUs.