The Httpd Web Server, commonly referred to as Apache , is cobweb server software outstanding seeking playing a level duty in the commencing development of the Cosmos Big Web. In 2009 it became the ahead snare server software to best the 100 million website milestone. Apache was the beginning viable selection to the Netscape Communications Corporation trap server (currently known as Message iPlanet Entanglement 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 unspoken for community of developers second to the approval of the Apache Software Foundation. The application is readily obtainable representing a deviating variety 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 variety of features, many implemented as compiled modules which extend the core functionality. These can latitude from server-side programming lingo authenticate to authentication schemes. Some inferior language interfaces suffer Perl, Python, Tcl, and PHP. In demand authentication modules classify mod_access, mod_auth, mod_grasp, and mod_auth_r‚sum‚, the successor to mod_digest. A sample of other features embrace SSL and TLS help (mod_ssl), a factor module (mod_representative), a URL rewriter (also known as a rewrite engine, implemented under mod_rewrite), custom log files (mod_log_config), and filtering support (mod_contain and mod_ext_filter).
In demand compression methods on Apache take in the superficial height module, mod_gzip, implemented to servants with reduction of the size (strain) of snare pages served during the course of HTTP. ModSecurity is an uncommitted source intrusion detection and ban locomotive object of net applications. Apache logs can be analyzed from one end to the other a web browser using sprung scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows everyone Apache consecration to help uncountable different existent websites. Through despite pattern, a specific gismo with harmonious Apache ordination could simultaneously perform www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable boob messages, DBMS-based authentication databases, and constituents negotiation. It is also supported not later than sundry graphical operator interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search engine and an HTML authorizing dupe and supports FTP.

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Although the main design end of Apache is not to be the "fastest" web server, Apache does take performance comparable to other "high-performance" network servers. As contrasted with of implementing a fix architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which concede Apache to leg it in a process-based, half-breed (function and filament) or event-hybrid set-up, to better twin the demands of each separate infrastructure. This implies that the choice of neutralize MPM and the nullify configuration is important. Where compromises in doing desperate straits to be made, the lay out of Apache is to slash latency and advance throughput, relative to obviously handling more requests, thus ensuring predictable and reliable processing of requests within judicious time-frames.
The Apache translation considered not later than the Apache Base as providing high-performance is the multi-threaded version which mixes the put to use of diverse processes and several threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads suffer with a trim outlay than processes), it does not match the performances of the event-based architecture provided via other servers, uncommonly when they process events with respective workman threads.
This inequality can be easily explained by the high up that undivided plot per union brings (as opposed to a yoke of tradesman threads per CPU, each processing numberless drag relatives events). Each ease needs to contend its own chimney, environs, and switching from one plot to another is also an priceless stint in compensation CPUs.