The Apache HTTP Server, commonly referred to as Apache , is snare server software matchless for the purpose playing a timbre place in the introductory success of the Society Extensive Web. In 2009 it became the ahead web server software to pass beyond the 100 million website milestone. Apache was the chief viable selection to the Netscape Communications Corporation web server (currently known as Augury iPlanet Entanglement Server), and has since evolved to compete with other web servers in terms of functionality and performance. Typically Apache is escape 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 for 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 be accurate 63% of all websites and 66% of the million busiest.
Features

Apache supports a mixture of features, tons implemented as compiled modules which proffer the gist functionality. These can range from server-side programming communication stick up for to authentication schemes. Some community words interfaces support Perl, Python, Tcl, and PHP. Favoured authentication modules include mod_access, mod_auth, mod_digest, and mod_auth_digest, the successor to mod_digest. A example of other features comprise SSL and TLS support (mod_ssl), a proxy module (mod_agent), a URL rewriter (also known as a rewrite locomotive, implemented high mod_rewrite), routine log files (mod_log_config), and filtering affirm (mod_contain and mod_ext_filter).
Popular compression methods on Apache allow for the external extension module, mod_gzip, implemented to servants with reduction of the appraise (weight) of cobweb pages served during the course of HTTP. ModSecurity is an available fountain-head intrusion detection and interception locomotive for cobweb applications. Apache logs can be analyzed through a cobweb browser using delivered scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows everyone Apache consecration to one's duty multitudinous diverse actual websites. Allowing for regarding example, the same machine with united Apache swearing-in could simultaneously serve www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and capacity negotiation. It is also supported near respective graphical consumer interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing tool and supports FTP.

Engagement


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Although the sheer cabal object of Apache is not to be the "fastest" web server, Apache does entertain performance comparable to other "high-performance" network servers. Instead of implementing a individual architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which deduct Apache to hump it in a process-based, hybrid (process and thread) or event-hybrid look, to excel blend the demands of each separate infrastructure. This implies that the select of chasten MPM and the nullify configuration is important. Where compromises in doing lack to be made, the stratagem of Apache is to slash latency and increase throughput, associated to simply handling more requests, in which case ensuring accordant and reliable processing of requests within reasonable time-frames.
The Apache translation considered by the Apache Foundation as providing high-performance is the multi-threaded style which mixes the put to use of very many processes and diverse threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads have a deign upper basic than processes), it does not match the performances of the event-based architecture provided via other servers, especially when they procedure events with respective worker threads.
This inequality can be easily explained on the high up that a man thread per connection brings (as opposed to a four of breadwinner threads per CPU, each processing numberless interplay events). Each ease needs to maintain its own load, milieu, and switching from one plot to another is also an valuable assignment for CPUs.