The Apache HTTP Server, commonly referred to as Apache , is web server software notable seeking playing a level place in the introductory growth of the Set Big Web. In 2009 it became the first web server software to surpass the 100 million website milestone. Apache was the first feasible different to the Netscape Communications Corporation cobweb server (currently known as Oracle iPlanet Snare Server), and has since evolved to contest other entanglement 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 underneath the approval of the Apache Software Foundation. The utilization is readily obtainable representing a wide 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 Allow, Apache is open-source software.
Since April 1996 Apache has been the most normal 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 mixture of features, varied implemented as compiled modules which proffer the core functionality. These can latitude from server-side programming language stick up for to authentication schemes. Some community lingua franca interfaces support Perl, Python, Tcl, and PHP. Popular authentication modules comprehend mod_access, mod_auth, mod_pr‚cis, and mod_auth_digest, the successor to mod_digest. A sample of other features classify SSL and TLS supporter (mod_ssl), a representative module (mod_substitute), a URL rewriter (also known as a rewrite engine, implemented high mod_rewrite), routine log files (mod_log_config), and filtering reinforce (mod_register and mod_ext_eliminate).
Stock compression methods on Apache allow for the external dimensions module, mod_gzip, implemented to improve with reduction of the area (weight) of web pages served to HTTP. ModSecurity is an available fountain-head intrusion detection and enjoining machine exchange for net applications. Apache logs can be analyzed through a cobweb browser using delivered scripts such as AWStats/W3Perl or Visitors.
Essential hosting allows united Apache installation to help uncountable unalike verifiable websites. On benchmark, the same gismo with harmonious Apache ordination could simultaneously be in the service of www.example.com, www.test.com, evaluate47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and constituents negotiation. It is also supported not later than sundry graphical drug interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search locomotive and an HTML authorizing dupe and supports FTP.

Performance


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Although the sheer cabal goal of Apache is not to be the "fastest" entanglement server, Apache does entertain performance comparable to other "high-performance" network servers. Instead of implementing a fix architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which allow Apache to skip out in a process-based, composite (process and thread) or event-hybrid look, to think twice blend the demands of each discriminating infrastructure. This implies that the select of neutralize MPM and the mark configuration is important. Where compromises in performance need to be made, the design of Apache is to reduce latency and increase throughput, relative to na‹vely handling more requests, in which case ensuring predictable and secure processing of requests within logical time-frames.
The Apache version considered past the Apache Foundation as providing high-performance is the multi-threaded version which mixes the manipulate of diverse processes and several threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads have a deign outlay than processes), it does not copy the performances of the event-based architecture provided via other servers, uniquely when they procedure events with a handful workman threads.
This difference can be easily explained by means of the skyward that a man filament per interrelationship brings (as opposed to a yoke of tradesman threads per CPU, each processing numberless interplay events). Each squeeze through needs to uphold its own clamp, habitat, and switching from one plot to another is also an priceless assignment for CPUs.