The Httpd Web Server, commonly referred to as Apache , is cobweb server software outstanding for playing a timbre duty in the commencing success of the Set Big Web. In 2009 it became the principal web server software to surpass the 100 million website milestone. Apache was the beginning rapport alternative to the Netscape Communications Corporation web server (currently known as Augury iPlanet Snare Server), and has since evolved to rival other web servers in terms of functionality and performance. Typically Apache is run on a Unix-like operating system.
Apache is developed and maintained not later than an bare community of developers under the sanction of the Apache Software Foundation. The application is readily obtainable on 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 be accurate 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, many implemented as compiled modules which proffer the pit functionality. These can choice from server-side programming language stick up for to authentication schemes. Some inferior words interfaces guy Perl, Python, Tcl, and PHP. In demand authentication modules take in mod_access, mod_auth, mod_digest, and mod_auth_synopsis, the successor to mod_digest. A illustration of other features include SSL and TLS stick (mod_ssl), a factor module (mod_agent), a URL rewriter (also known as a rewrite appliance, implemented supervised mod_rewrite), custom log files (mod_log_config), and filtering support (mod_register and mod_ext_filter).
Sought-after compression methods on Apache categorize the superficial augmentation module, mod_gzip, implemented to improve with reduction of the size (weight) of snare pages served to HTTP. ModSecurity is an open rise intrusion detection and interception engine object of cobweb applications. Apache logs can be analyzed in the course a snare browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows everyone Apache consecration to fulfil many divers physical websites. Through despite pattern, one mechanism with harmonious Apache swearing-in could simultaneously favourable to www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and capacity negotiation. It is also supported near disparate graphical user interfaces (GUIs).
It supports password authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing tool and supports FTP.

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Although the main design object of Apache is not to be the "fastest" web server, Apache does play a joke on playing comparable to other "high-performance" network servers. A substitute alternatively of implementing a only architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which deduct Apache to leg it in a process-based, composite (function and filament) or event-hybrid mode, to think twice match the demands of each separate infrastructure. This implies that the select of chasten MPM and the mark configuration is important. Where compromises in dispatch lack to be made, the stratagem of Apache is to reduce latency and increase throughput, dependent on to austerely handling more requests, that reason ensuring accordant and trusted processing of requests within reasonable time-frames.
The Apache version considered past the Apache Base as providing high-performance is the multi-threaded translation which mixes the use of several processes and diverse threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads have a deign running costs than processes), it does not compare with the performances of the event-based architecture provided by other servers, uncommonly when they change events with a variety of hand threads.
This distinction can be without even trying explained beside the aloft that undivided thread per relevance brings (as opposed to a twosome of tradesman threads per CPU, each processing many drag relatives events). Each squeeze through needs to contend its own load, milieu, and switching from joke theme to another is also an valuable assignment for CPUs.