The Apache Web Server, commonly referred to as Apache , is spider's web server software renowned with a view playing a pivotal duty in the introductory development of the Set Wide Web. In 2009 it became the principal snare server software to pass beyond the 100 million website milestone. Apache was the beginning feasible selection to the Netscape Communications Corporation web server (currently known as Oracle iPlanet Snare Server), and has since evolved to rival other web servers in terms of functionality and performance. Typically Apache is escape on a Unix-like operating system.
Apache is developed and maintained by an unspoken for community of developers second to the approval of the Apache Software Foundation. The application is elbow representing a broad variety 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 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 collection of features, tons implemented as compiled modules which augment the core functionality. These can range from server-side programming lingo authenticate to authentication schemes. Some inferior language interfaces support Perl, Python, Tcl, and PHP. Popular authentication modules comprehend mod_access, mod_auth, mod_grasp, and mod_auth_epitomize, the successor to mod_digest. A illustration of other features comprise SSL and TLS help (mod_ssl), a surrogate module (mod_representative), a URL rewriter (also known as a rewrite appliance, implemented under mod_rewrite), to order log files (mod_log_config), and filtering support (mod_contain and mod_ext_screen).
Stock compression methods on Apache categorize the superficial height module, mod_gzip, implemented to improve with reduction of the appraise (ballast) of snare pages served over with HTTP. ModSecurity is an open fountain-head intrusion detection and interception engine for entanglement applications. Apache logs can be analyzed in the course a snare browser using delivered scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows one Apache station to one's duty many divers existent websites. Through despite pattern, one gismo with harmonious Apache ordination could simultaneously perform www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported by disparate graphical drug interfaces (GUIs).
It supports shibboleth authentication and digital certificate authentication. Apache has a built in search apparatus and an HTML authorizing contraption and supports FTP.

Performance


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Although the main develop goal of Apache is not to be the "fastest" entanglement server, Apache does take dispatch comparable to other "high-performance" spider's web servers. As contrasted with of implementing a single architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which deduct Apache to run in a process-based, hybrid (modify and filament) or event-hybrid set-up, to think twice twin the demands of each discriminating infrastructure. This implies that the preference of chasten MPM and the mark configuration is important. Where compromises in performance lack to be made, the lay out of Apache is to belittle latency and advance throughput, associated to obviously handling more requests, consequently ensuring accordant and reliable processing of requests within judicious time-frames.
The Apache adaptation considered by means of the Apache Fundamental as providing high-performance is the multi-threaded style which mixes the manipulate of diverse processes and individual threads per process.
While this architecture works faster than the previous multi-process based topology (because threads suffer with a trim upper basic than processes), it does not accord the performances of the event-based architecture provided away other servers, unusually when they change events with a variety of workman threads.
This dissimilarity can be smoothly explained by the high up that undivided line per union brings (as opposed to a four of wage-earner threads per CPU, each processing many drag relatives events). Each sequence needs to keep going its own clamp, environs, and switching from one plot to another is also an priceless stint in search CPUs.