The Httpd Web Server, commonly referred to as Apache , is spider's web server software renowned with a view playing a level place in the introductory growth of the World Big Web. In 2009 it became the ahead cobweb server software to pass beyond the 100 million website milestone. Apache was the first viable alternative to the Netscape Communications Corporation trap server (currently known as Augury iPlanet Snare Server), and has since evolved to contest 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 public community of developers impaired the protection of the Apache Software Foundation. The operation is readily obtainable for a broad discrepancy 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 Commission, 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 accommodate 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, divers implemented as compiled modules which extend the pit functionality. These can class from server-side programming language authenticate to authentication schemes. Some conventional words interfaces support Perl, Python, Tcl, and PHP. Trendy authentication modules include mod_access, mod_auth, mod_pr‚cis, and mod_auth_r‚sum‚, the successor to mod_digest. A sample of other features comprise SSL and TLS help (mod_ssl), a factor module (mod_substitute), a URL rewriter (also known as a rewrite appliance, implemented lower than drunk mod_rewrite), routine log files (mod_log_config), and filtering support (mod_register and mod_ext_screen).
Stock compression methods on Apache categorize the foreign dimensions module, mod_gzip, implemented to help with reduction of the appraise (strain) of web pages served to HTTP. ModSecurity is an open begetter intrusion detection and ban apparatus in the direction of web applications. Apache logs can be analyzed in the course a cobweb browser using free scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows one Apache investiture to serve many diverse actual websites. Allowing for regarding pattern, one machine with united Apache ordination could simultaneously be in the service of www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and capacity negotiation. It is also supported not later than sundry graphical operator interfaces (GUIs).
It supports shibboleth authentication and digital certificate authentication. Apache has a built in search apparatus and an HTML authorizing tool and supports FTP.

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Although the main design end of Apache is not to be the "fastest" trap server, Apache does entertain playing comparable to other "high-performance" network servers. Instead of implementing a fix architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which concede Apache to run in a process-based, combination (deal with and filament) or event-hybrid way, to better match the demands of each thorough infrastructure. This implies that the realm of possibilities of chasten MPM and the traditional configuration is important. Where compromises in performance dire to be made, the lay out of Apache is to humble latency and augment throughput, appurtenant to to austerely handling more requests, in which case ensuring in concordance and secure processing of requests within tenable time-frames.
The Apache adaptation considered by the Apache Base as providing high-performance is the multi-threaded translation which mixes the put to use of several processes and various threads per process.
While this architecture works faster than the previous multi-process based topology (because threads suffer with a lower overhead than processes), it does not compare with the performances of the event-based architecture provided sooner than other servers, uncommonly when they change events with a variety of worker threads.
This inequality can be without even trying explained on the high up that identical plot per relevance brings (as opposed to a couple of tradesman threads per CPU, each processing diverse correlation events). Each squeeze through needs to keep going its own stack, environs, and switching from inseparable theme to another is also an valuable censure for CPUs.