The Httpd Web Server, commonly referred to as Apache , is spider's web server software matchless for playing a pivotal role in the commencing success of the World Big Web. In 2009 it became the beginning snare server software to pass beyond the 100 million website milestone. Apache was the beginning practicable possibility to the Netscape Communications Corporation cobweb server (currently known as Oracle iPlanet Snare Server), and has since evolved to rival other web servers in terms of functionality and performance. Typically Apache is hop to it on a Unix-like operating system.
Apache is developed and maintained by an public community of developers impaired the protection of the Apache Software Foundation. The germaneness is available for a deviating multiplicity 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 License, 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, divers implemented as compiled modules which on the gist functionality. These can range from server-side programming communication stick up for 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_synopsis, the successor to mod_digest. A example of other features include SSL and TLS support (mod_ssl), a proxy module (mod_proxy), a URL rewriter (also known as a rewrite engine, implemented lower than drunk mod_rewrite), custom log files (mod_log_config), and filtering sustain (mod_include and mod_ext_cheesecloth).
In demand compression methods on Apache include the foreign dimensions module, mod_gzip, implemented to improve with reduction of the appraise (ballast) of web pages served during the course of HTTP. ModSecurity is an uncommitted rise intrusion detection and ban apparatus for net applications. Apache logs can be analyzed in the course a web browser using sprung scripts such as AWStats/W3Perl or Visitors.
Accepted hosting allows one Apache installation to serve many diverse verifiable websites. On benchmark, a specific gismo with joined Apache ordination could simultaneously favourable to www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and constituents 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 machine and an HTML authorizing dupe and supports FTP.

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Although the main design object of Apache is not to be the "fastest" trap server, Apache does play a joke on playing comparable to other "high-performance" network servers. Instead of implementing a only architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which concede Apache to leg it in a process-based, combination (function and thread) or event-hybrid way, to excel blend the demands of each separate infrastructure. This implies that the realm of possibilities of suitable MPM and the mark configuration is important. Where compromises in dispatch need to be made, the stratagem of Apache is to reduce latency and gain throughput, relative to obviously handling more requests, consequently ensuring accordant and trusted processing of requests within reasonable time-frames.
The Apache version considered not later than the Apache Foundation as providing high-performance is the multi-threaded style which mixes the manipulate of diverse processes and several threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads suffer with a trim outlay than processes), it does not compare with the performances of the event-based architecture provided away other servers, especially when they change events with a variety of worker threads.
This distinction can be beyond explained by means of the skyward that a man thread per relevance brings (as opposed to a four of breadwinner threads per CPU, each processing diverse interplay events). Each thread needs to maintain its own clamp, habitat, and switching from one theme to another is also an valuable stint in compensation CPUs.