The Apache Web Server, commonly referred to as Apache , is web server software matchless with a view playing a timbre place in the commencing success of the World Sizeable Web. In 2009 it became the principal spider's web server software to best the 100 million website milestone. Apache was the beginning viable alternative to the Netscape Communications Corporation network server (currently known as Seer iPlanet Snare Server), and has since evolved to rival other entanglement 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 open community of developers impaired the sanction of the Apache Software Foundation. The utilization is ready representing 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 supervised 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 collection of features, tons implemented as compiled modules which proffer the pit functionality. These can range from server-side programming communication stick up for to authentication schemes. Some conventional lingua franca interfaces suffer Perl, Python, Tcl, and PHP. Trendy authentication modules classify mod_access, mod_auth, mod_grasp, and mod_auth_synopsis, the successor to mod_digest. A representation of other features embrace SSL and TLS support (mod_ssl), a representative module (mod_representative), a URL rewriter (also known as a rewrite locomotive, implemented high mod_rewrite), routine log files (mod_log_config), and filtering sustain (mod_contain and mod_ext_filter).
In demand compression methods on Apache include the exotic height module, mod_gzip, implemented to ease with reduction of the area (strain) of cobweb pages served to HTTP. ModSecurity is an available source intrusion detection and interception locomotive in the direction of net applications. Apache logs can be analyzed help of a entanglement browser using sprung scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows everyone Apache investiture to help innumerable unalike physical websites. For benchmark, one machine with harmonious Apache installation could simultaneously perform www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable boob messages, DBMS-based authentication databases, and capacity negotiation. It is also supported next to sundry graphical consumer interfaces (GUIs).
It supports watchword 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 primary develop goal of Apache is not to be the "fastest" web server, Apache does play a joke on fulfilment comparable to other "high-performance" web servers. A substitute alternatively of implementing a fix architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which concede Apache to hump it in a process-based, hybrid (process and filament) or event-hybrid look, to superior blend the demands of each discriminating infrastructure. This implies that the choice of chasten MPM and the nullify configuration is important. Where compromises in doing need to be made, the conceive of Apache is to reduce latency and augment throughput, dependent on to obviously handling more requests, that reason ensuring in concordance and reliable processing of requests within tenable time-frames.
The Apache reading considered not later than the Apache Base as providing high-performance is the multi-threaded adaptation which mixes the use of very many processes and diverse threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads set up a deign running costs than processes), it does not match the performances of the event-based architecture provided by other servers, especially when they process events with respective workman threads.
This difference can be easily explained by means of the aloft that a man filament per relevance brings (as opposed to a twosome of breadwinner threads per CPU, each processing profuse interplay events). Each thread needs to maintain its own stack, habitat, and switching from in unison theme to another is also an expensive task for CPUs.