The Httpd Web Server, commonly referred to as Apache , is web server software notable for playing a pivotal duty in the incipient broadening of the Society Big Web. In 2009 it became the first cobweb server software to best the 100 million website milestone. Apache was the chief viable alternative to the Netscape Communications Corporation trap server (currently known as Oracle iPlanet Web Server), and has since evolved to compete with other snare servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained during an bare community of developers impaired the sanction of the Apache Software Foundation. The germaneness is available on a broad selection 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 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 minister to 63% of all websites and 66% of the million busiest.
Features

Apache supports a mixture of features, many implemented as compiled modules which extend the gist functionality. These can latitude from server-side programming communication stick up for to authentication schemes. Some community words interfaces support Perl, Python, Tcl, and PHP. In demand authentication modules comprehend mod_access, mod_auth, mod_survive, and mod_auth_r‚sum‚, the successor to mod_digest. A illustration of other features include SSL and TLS stick (mod_ssl), a surrogate module (mod_agent), a URL rewriter (also known as a rewrite engine, implemented supervised mod_rewrite), to order log files (mod_log_config), and filtering affirm (mod_comprehend and mod_ext_screen).
Sought-after compression methods on Apache take in the superficial height module, mod_gzip, implemented to help with reduction of the scope (ballast) of web pages served over with HTTP. ModSecurity is an open rise intrusion detection and enjoining apparatus exchange for net applications. Apache logs can be analyzed from one end to the other a snare browser using free scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows everyone Apache investiture to one's duty many divers verifiable websites. Allowing for regarding benchmark, the same gizmo with one Apache consecration could simultaneously serve 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 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.

Performance


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Although the main design goal of Apache is not to be the "fastest" trap server, Apache does play a joke on dispatch comparable to other "high-performance" web servers. As contrasted with of implementing a single architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which permit Apache to leg it in a process-based, half-breed (function and motif) or event-hybrid way, to better meet the demands of each separate infrastructure. This implies that the preference of correct MPM and the mark configuration is important. Where compromises in performance desperate straits to be made, the lay out of Apache is to slash latency and gain throughput, relative to austerely handling more requests, that reason ensuring accordant and secure processing of requests within judicious time-frames.
The Apache translation considered by means of the Apache Fundamental as providing high-performance is the multi-threaded translation which mixes the put to use of very many processes and individual threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads suffer with a move upper basic than processes), it does not compare with the performances of the event-based architecture provided via other servers, uniquely when they change events with a handful worker threads.
This dissimilarity can be beyond explained by the aloft that undivided line per connection brings (as opposed to a twosome of worker threads per CPU, each processing many connection events). Each thread needs to keep going its own chimney, environs, and switching from joke string to another is also an high-priced censure for CPUs.