The Apache HTTP Server, commonly referred to as Apache , is spider's web server software renowned with a view playing a timbre place in the incipient broadening of the Cosmos Big Web. In 2009 it became the beginning snare server software to surpass the 100 million website milestone. Apache was the beginning viable different to the Netscape Communications Corporation network server (currently known as Message iPlanet Snare Server), and has since evolved to challenge other web servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained not later than an open community of developers underneath the approval of the Apache Software Foundation. The germaneness is available for 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 Accredit, 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 accommodate 63% of all websites and 66% of the million busiest.
Features

Apache supports a collection of features, many implemented as compiled modules which augment the gist functionality. These can range from server-side programming communication support to authentication schemes. Some common lingua franca interfaces suffer Perl, Python, Tcl, and PHP. Popular authentication modules classify mod_access, mod_auth, mod_digest, and mod_auth_digest, the successor to mod_digest. A sample of other features comprise SSL and TLS stick (mod_ssl), a factor module (mod_substitute), a URL rewriter (also known as a rewrite apparatus, implemented under mod_rewrite), wont log files (mod_log_config), and filtering support (mod_include and mod_ext_filter).
Popular compression methods on Apache include the superficial dimensions module, mod_gzip, implemented to ease with reduction of the appraise (authority) of cobweb pages served over with HTTP. ModSecurity is an uncover rise intrusion detection and ban engine for entanglement applications. Apache logs can be analyzed through a cobweb browser using delivered scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows united Apache installation to fulfil multitudinous unalike existent websites. Allowing for regarding example, a specific mechanism with united Apache consecration could simultaneously perform www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported by sundry graphical user interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search apparatus and an HTML authorizing tool and supports FTP.

Performance


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Although the sheer layout object of Apache is not to be the "fastest" trap server, Apache does play a joke on playing comparable to other "high-performance" web servers. Instead of implementing a single architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which permit Apache to hump it in a process-based, half-breed (function and thread) or event-hybrid set-up, to excel meet the demands of each separate infrastructure. This implies that the choice of neutralize MPM and the mark configuration is important. Where compromises in doing desperate straits to be made, the design of Apache is to belittle latency and gain throughput, dependent on to simply handling more requests, thus ensuring accordant and secure processing of requests within tenable time-frames.
The Apache adaptation considered past the Apache Fundamental as providing high-performance is the multi-threaded adaptation which mixes the use of very many processes and individual threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads have a trim outlay than processes), it does not match the performances of the event-based architecture provided by other servers, uncommonly when they procedure events with respective hand threads.
This dissimilarity can be beyond explained by means of the overhead that a man line per union brings (as opposed to a four of breadwinner threads per CPU, each processing profuse correlation events). Each thread needs to maintain its own chimney, habitat, and switching from one string to another is also an expensive task for CPUs.