The Apache Web Server, commonly referred to as Apache , is cobweb server software matchless seeking playing a pivotal capacity in the incipient success of the Society Wide Web. In 2009 it became the principal web server software to surpass the 100 million website milestone. Apache was the chief practicable possibility to the Netscape Communications Corporation network server (currently known as Message iPlanet Entanglement 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 during an public community of developers impaired the auspices of the Apache Software Foundation. The germaneness is ready instead of a broad multiplicity 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 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 accommodate 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 gist functionality. These can latitude from server-side programming communication assist to authentication schemes. Some common lingua franca interfaces buttress Perl, Python, Tcl, and PHP. In demand authentication modules comprehend mod_access, mod_auth, mod_pr‚cis, and mod_auth_synopsis, the successor to mod_digest. A example of other features classify SSL and TLS supporter (mod_ssl), a factor module (mod_representative), a URL rewriter (also known as a rewrite apparatus, implemented supervised mod_rewrite), wont log files (mod_log_config), and filtering support (mod_register and mod_ext_eliminate).
In demand compression methods on Apache include the exotic extension module, mod_gzip, implemented to ease with reduction of the scope (weight) of snare pages served to HTTP. ModSecurity is an uncommitted source intrusion detection and enjoining apparatus for entanglement applications. Apache logs can be analyzed through a web browser using free scripts such as AWStats/W3Perl or Visitors.
Accepted hosting allows one Apache station to fulfil many different verifiable websites. For model, one gismo with joined Apache consecration could simultaneously favourable to www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and capacity negotiation. It is also supported next to several graphical operator interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing contraption and supports FTP.

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Although the sheer cabal end of Apache is not to be the "fastest" web server, Apache does have dispatch comparable to other "high-performance" web servers. Instead of implementing a fix architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which allow Apache to leg it in a process-based, combination (deal with and thread) or event-hybrid way, to excel blend the demands of each separate infrastructure. This implies that the select of chasten MPM and the mark configuration is important. Where compromises in performance dire to be made, the conceive of Apache is to humble latency and advance throughput, associated to simply handling more requests, thus ensuring predictable and reliable processing of requests within judicious time-frames.
The Apache reading considered not later than the Apache Endowment as providing high-performance is the multi-threaded translation which mixes the manipulate of a handful processes and diverse threads per process.
While this architecture works faster than the previous multi-process based topology (because threads set up a lower overhead than processes), it does not accord the performances of the event-based architecture provided away other servers, especially when they procedure events with several workman threads.
This inequality can be without even trying explained by the skyward that one plot per interrelationship brings (as opposed to a couple of tradesman threads per CPU, each processing numberless connection events). Each thread needs to keep going its own load, environs, and switching from one string to another is also an priceless censure in compensation CPUs.