The Apache Web Server, commonly referred to as Apache , is spider's web server software notable seeking playing a level capacity in the incipient broadening of the Cosmos Extensive Web. In 2009 it became the ahead web server software to surpass the 100 million website milestone. Apache was the chief viable different to the Netscape Communications Corporation web server (currently known as Oracle 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 during an unspoken for community of developers impaired the auspices of the Apache Software Foundation. The operation is ready instead of a broad 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 License, Apache is open-source software.
Since April 1996 Apache has been the most conventional 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 mixture of features, tons implemented as compiled modules which on the gist functionality. These can class from server-side programming language support to authentication schemes. Some community language interfaces support Perl, Python, Tcl, and PHP. Trendy authentication modules take in mod_access, mod_auth, mod_grasp, and mod_auth_epitomize, the successor to mod_digest. A illustration of other features comprise SSL and TLS support (mod_ssl), a representative module (mod_substitute), a URL rewriter (also known as a rewrite engine, implemented under mod_rewrite), wont log files (mod_log_config), and filtering sustain (mod_register and mod_ext_filter).
Sought-after compression methods on Apache take in the foreign height module, mod_gzip, implemented to servants with reduction of the size (weight) of web pages served over with HTTP. ModSecurity is an uncover source intrusion detection and enjoining locomotive object of entanglement applications. Apache logs can be analyzed through a cobweb browser using delivered scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows song Apache installation to help uncountable different existent websites. Allowing for regarding example, the same machine with joined Apache swearing-in could simultaneously serve www.example.com, www.test.com, evaluate47.test-server.test.com, etc.
Apache features configurable error messages, DBMS-based authentication databases, and content negotiation. It is also supported not later than several 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 sheer layout aspiration of Apache is not to be the "fastest" entanglement server, Apache does entertain playing comparable to other "high-performance" spider's web servers. As contrasted with of implementing a individual architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which allow Apache to skip out in a process-based, composite (modify and filament) or event-hybrid way, to think twice meet the demands of each separate infrastructure. This implies that the realm of possibilities of suitable MPM and the correct configuration is important. Where compromises in performance desperate straits to be made, the stratagem of Apache is to belittle latency and increase throughput, dependent on to austerely handling more requests, in which case ensuring consistent and trusted processing of requests within tenable time-frames.
The Apache adaptation considered by the Apache Base as providing high-performance is the multi-threaded style which mixes the manipulate of diverse processes and various threads per process.
While this architecture works faster than the previous multi-process based topology (because threads suffer with a move overhead than processes), it does not accord the performances of the event-based architecture provided away other servers, especially when they process events with several wage-earner threads.
This distinction can be beyond explained by the overhead that a man thread per union brings (as opposed to a yoke of worker threads per CPU, each processing profuse interplay events). Each ease needs to uphold its own chimney, milieu, and switching from inseparable thread to another is also an priceless task after CPUs.