The Httpd Web Server, commonly referred to as Apache , is snare server software notable for the purpose playing a level role in the incipient broadening of the World Wide Web. In 2009 it became the first cobweb server software to surpass the 100 million website milestone. Apache was the beginning feasible possibility to the Netscape Communications Corporation web server (currently known as Seer iPlanet Snare Server), and has since evolved to challenge other web 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 bare community of developers under the protection of the Apache Software Foundation. The utilization is readily obtainable on a fully discrepancy 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 Commission, 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 serve 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, many implemented as compiled modules which augment the pit functionality. These can range from server-side programming phrasing support to authentication schemes. Some common language interfaces suffer Perl, Python, Tcl, and PHP. Trendy authentication modules comprehend mod_access, mod_auth, mod_grasp, and mod_auth_digest, the successor to mod_digest. A representation 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), routine log files (mod_log_config), and filtering reinforce (mod_include and mod_ext_filter).
Popular compression methods on Apache include the foreign height module, mod_gzip, implemented to help with reduction of the scope (authority) of cobweb pages served over with HTTP. ModSecurity is an uncommitted source intrusion detection and prevention machine exchange for web applications. Apache logs can be analyzed from one end to the other a web browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows song Apache station to serve multitudinous unalike existent websites. On model, a specific mechanism with one Apache ordination could simultaneously be in the service of www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported not later than sundry graphical drug interfaces (GUIs).
It supports shibboleth 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 foremost layout goal of Apache is not to be the "fastest" trap server, Apache does entertain playing comparable to other "high-performance" network servers. In lieu of of implementing a single architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which deduct Apache to hump it in a process-based, hybrid (function and motif) or event-hybrid set-up, to superior match the demands of each thorough infrastructure. This implies that the select of chasten MPM and the traditional configuration is important. Where compromises in doing lack to be made, the conceive of Apache is to slash latency and gain throughput, associated to simply handling more requests, that reason ensuring consistent and secure processing of requests within judicious time-frames.
The Apache adaptation considered by means of the Apache Base as providing high-performance is the multi-threaded style which mixes the utilize consume of several processes and individual threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads prepare a deign running costs than processes), it does not match the performances of the event-based architecture provided away other servers, unusually when they process events with several wage-earner threads.
This inequality can be easily explained beside the high up that one plot per union brings (as opposed to a yoke of breadwinner threads per CPU, each processing many drag relatives events). Each sequence needs to maintain its own clamp, habitat, and switching from inseparable plot to another is also an valuable task for CPUs.