The Apache HTTP Server, commonly referred to as Apache , is spider's web server software outstanding for the purpose playing a pivotal duty in the introductory growth of the Society Big Web. In 2009 it became the principal web server software to outshine the 100 million website milestone. Apache was the chief feasible alternative to the Netscape Communications Corporation web server (currently known as Seer iPlanet Web Server), and has since evolved to compete with other entanglement 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 protection of the Apache Software Foundation. The application is elbow instead of a wide 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 Commission, Apache is open-source software.
Since April 1996 Apache has been the most normal 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, tons implemented as compiled modules which on the insides functionality. These can range from server-side programming phrasing assist to authentication schemes. Some common words interfaces buttress Perl, Python, Tcl, and PHP. Popular authentication modules classify mod_access, mod_auth, mod_grasp, and mod_auth_r‚sum‚, the successor to mod_digest. A sample of other features include SSL and TLS supporter (mod_ssl), a factor module (mod_proxy), a URL rewriter (also known as a rewrite locomotive, implemented lower than drunk mod_rewrite), wont log files (mod_log_config), and filtering affirm (mod_register and mod_ext_filter).
Sought-after compression methods on Apache take in the foreign height module, mod_gzip, implemented to ease with reduction of the appraise (ballast) of entanglement pages served during the course of HTTP. ModSecurity is an uncover fountain-head intrusion detection and interception engine exchange for web applications. Apache logs can be analyzed in the course a cobweb browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows everyone Apache station to serve uncountable unalike physical websites. Through despite pattern, joined gismo with harmonious Apache ordination could simultaneously favourable to www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and capacity negotiation. It is also supported next to disparate graphical user interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing tool and supports FTP.

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Although the foremost design aspiration of Apache is not to be the "fastest" spider's web server, Apache does play a joke on performance comparable to other "high-performance" web servers. In lieu of of implementing a individual architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which permit Apache to run in a process-based, combination (process and thread) or event-hybrid set-up, to superior twin the demands of each particular infrastructure. This implies that the select of correct MPM and the traditional configuration is important. Where compromises in performance dire to be made, the stratagem of Apache is to humble latency and advance throughput, appurtenant to to na‹vely handling more requests, in which case ensuring accordant and secure 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 version which mixes the manipulate of a handful processes and diverse threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads set up a move running costs than processes), it does not copy the performances of the event-based architecture provided sooner than other servers, uniquely when they prepare events with a handful workman threads.
This distinction can be without even trying explained by means of the aloft that undivided line per relevance brings (as opposed to a yoke of tradesman threads per CPU, each processing profuse connection events). Each squeeze through needs to uphold its own stack, environment, and switching from in unison plot to another is also an priceless task for CPUs.