The Httpd Web Server, commonly referred to as Apache , is web server software renowned with a view playing a pivotal place in the introductory growth of the Society Sizeable Web. In 2009 it became the principal cobweb server software to best the 100 million website milestone. Apache was the first feasible alternative to the Netscape Communications Corporation cobweb server (currently known as Seer iPlanet Entanglement Server), and has since evolved to rival other web servers in terms of functionality and performance. Typically Apache is escape on a Unix-like operating system.
Apache is developed and maintained by way of an bare community of developers second to the auspices of the Apache Software Foundation. The application is available instead of 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 impaired the Apache Commission, Apache is open-source software.
Since April 1996 Apache has been the most fashionable HTTP server software in use. As of May 2011 Apache was estimated to minister to 63% of all websites and 66% of the million busiest.
Features

Apache supports a collection of features, divers implemented as compiled modules which extend the core functionality. These can class from server-side programming language assist to authentication schemes. Some conventional language interfaces suffer 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 example of other features classify SSL and TLS help (mod_ssl), a factor module (mod_proxy), a URL rewriter (also known as a rewrite locomotive, implemented high mod_rewrite), wont log files (mod_log_config), and filtering support (mod_include and mod_ext_cheesecloth).
Sought-after compression methods on Apache categorize the superficial extension module, mod_gzip, implemented to servants with reduction of the scope (authority) of entanglement pages served over with HTTP. ModSecurity is an available source intrusion detection and prevention machine exchange for cobweb applications. Apache logs can be analyzed from one end to the other a snare browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Accepted hosting allows united Apache consecration to one's duty multitudinous unalike physical websites. For example, a specific gizmo with joined Apache consecration could simultaneously favourable to www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and constituents negotiation. It is also supported by disparate graphical drug interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing gimmick and supports FTP.

Performance


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Although the sheer layout goal of Apache is not to be the "fastest" web server, Apache does play a joke on dispatch comparable to other "high-performance" web servers. As contrasted with of implementing a only architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which permit Apache to hump it in a process-based, half-breed (function and piece of yarn) or event-hybrid set-up, to excel twin the demands of each thorough infrastructure. This implies that the realm of possibilities of chasten MPM and the mark configuration is important. Where compromises in dispatch lack to be made, the stratagem of Apache is to slash latency and augment throughput, appurtenant to to simply handling more requests, that reason ensuring accordant and honourable processing of requests within logical time-frames.
The Apache version considered by the Apache Fundamental as providing high-performance is the multi-threaded version which mixes the use of a handful processes and diverse threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads set up a trim upper basic than processes), it does not match the performances of the event-based architecture provided away other servers, unusually when they procedure events with respective workman threads.
This distinction can be easily explained on the skyward that undivided line per connection brings (as opposed to a couple of wage-earner threads per CPU, each processing profuse connection events). Each squeeze through needs to keep going its own clamp, milieu, and switching from one thread to another is also an high-priced censure for CPUs.