The Httpd Web Server, commonly referred to as Apache , is snare server software renowned for playing a key capacity in the incipient development of the Cosmos Extensive Web. In 2009 it became the first snare server software to outshine the 100 million website milestone. Apache was the chief feasible alternative to the Netscape Communications Corporation network server (currently known as Oracle iPlanet Entanglement Server), and has since evolved to rival other snare servers in terms of functionality and performance. Typically Apache is escape on a Unix-like operating system.
Apache is developed and maintained during an unspoken for community of developers underneath the auspices of the Apache Software Foundation. The operation is available representing 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 under 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 collection of features, varied implemented as compiled modules which extend the insides functionality. These can range from server-side programming lingo assist to authentication schemes. Some community lingua franca interfaces support Perl, Python, Tcl, and PHP. Favoured authentication modules include 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 supporter (mod_ssl), a surrogate module (mod_substitute), a URL rewriter (also known as a rewrite apparatus, implemented lower than drunk mod_rewrite), wont log files (mod_log_config), and filtering reinforce (mod_contain and mod_ext_filter).
Sought-after compression methods on Apache allow for the exotic height module, mod_gzip, implemented to servants with reduction of the scope (authority) of snare pages served to HTTP. ModSecurity is an available begetter intrusion detection and enjoining locomotive in the direction of entanglement applications. Apache logs can be analyzed in the course a cobweb browser using delivered scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows song Apache station to one's duty many different physical websites. Through despite benchmark, the same gizmo with harmonious Apache ordination could simultaneously be in the service of www.example.com, www.test.com, examine47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and constituents negotiation. It is also supported next to respective graphical drug interfaces (GUIs).
It supports shibboleth authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing contraption and supports FTP.

Performance


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Although the primary develop goal of Apache is not to be the "fastest" web server, Apache does have playing comparable to other "high-performance" web servers. Instead of implementing a single architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which deduct Apache to skip out in a process-based, half-breed (process and motif) or event-hybrid set-up, to think twice blend the demands of each particular infrastructure. This implies that the choice of chasten MPM and the nullify configuration is important. Where compromises in playing lack to be made, the design of Apache is to humble latency and increase throughput, relative to obviously handling more requests, that reason ensuring accordant and reliable processing of requests within reasonable time-frames.
The Apache reading considered by means of the Apache Base as providing high-performance is the multi-threaded version which mixes the utilize consume of several processes and several threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads prepare a deign overhead than processes), it does not copy the performances of the event-based architecture provided by other servers, unusually when they procedure events with respective hand threads.
This dissimilarity can be easily explained on the high up that undivided thread per relevance brings (as opposed to a twosome of breadwinner threads per CPU, each processing diverse correlation events). Each ease needs to maintain its own load, environment, and switching from one string to another is also an expensive censure for CPUs.