The Apache HTTP Server, commonly referred to as Apache , is snare server software outstanding seeking playing a timbre capacity in the introductory broadening of the Society Extensive Web. In 2009 it became the beginning snare server software to outshine the 100 million website milestone. Apache was the beginning rapport possibility to the Netscape Communications Corporation web server (currently known as Augury iPlanet Entanglement 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 by an open community of developers underneath the sanction of the Apache Software Foundation. The germaneness is readily obtainable for 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 supervised the Apache Commission, 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 accommodate 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, varied implemented as compiled modules which augment the gist functionality. These can range from server-side programming phrasing authenticate to authentication schemes. Some conventional jargon interfaces guy Perl, Python, Tcl, and PHP. In demand authentication modules take in mod_access, mod_auth, mod_digest, and mod_auth_digest, the successor to mod_digest. A representation of other features comprise SSL and TLS support (mod_ssl), a factor module (mod_agent), a URL rewriter (also known as a rewrite apparatus, implemented lower than drunk mod_rewrite), custom log files (mod_log_config), and filtering affirm (mod_register and mod_ext_eliminate).
Popular compression methods on Apache include the superficial height module, mod_gzip, implemented to servants with reduction of the size (authority) of entanglement pages served during the course of HTTP. ModSecurity is an uncommitted rise intrusion detection and enjoining engine exchange for web applications. Apache logs can be analyzed through a cobweb browser using free scripts such as AWStats/W3Perl or Visitors.
Essential hosting allows united Apache consecration to serve innumerable unalike existent websites. For pattern, a specific gizmo with harmonious Apache swearing-in could simultaneously favourable to 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 operator interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search engine and an HTML authorizing tool and supports FTP.

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Although the main layout object of Apache is not to be the "fastest" trap server, Apache does entertain performance comparable to other "high-performance" web servers. In lieu of of implementing a individual architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which allow Apache to hump it in a process-based, half-breed (function and piece of yarn) or event-hybrid mode, to better blend the demands of each discriminating infrastructure. This implies that the choice of chasten MPM and the traditional configuration is important. Where compromises in performance desperate straits to be made, the lay out of Apache is to humble latency and advance throughput, associated to obviously handling more requests, consequently ensuring in concordance and secure processing of requests within reasonable time-frames.
The Apache translation considered by means of the Apache Foundation as providing high-performance is the multi-threaded style which mixes the put to use of very many processes and individual threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads suffer with a lower overhead than processes), it does not accord the performances of the event-based architecture provided via other servers, uniquely when they process events with a variety of hand threads.
This difference can be smoothly explained on the aloft that one plot per union brings (as opposed to a couple of worker threads per CPU, each processing profuse interplay events). Each ease needs to contend its own stack, environs, and switching from joke string to another is also an expensive censure in search CPUs.