The Apache HTTP Server, commonly referred to as Apache , is spider's web server software outstanding for playing a pivotal role in the introductory growth of the Cosmos Sizeable Web. In 2009 it became the first web server software to pass beyond the 100 million website milestone. Apache was the chief practicable alternative to the Netscape Communications Corporation cobweb server (currently known as Message iPlanet Snare Server), and has since evolved to rival other entanglement servers in terms of functionality and performance. Typically Apache is run on a Unix-like operating system.
Apache is developed and maintained by an unspoken for community of developers under the sanction of the Apache Software Foundation. The application is readily obtainable on 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 impaired the Apache Accredit, 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 breed of features, tons implemented as compiled modules which proffer the gist functionality. These can class from server-side programming language assist to authentication schemes. Some common words interfaces support Perl, Python, Tcl, and PHP. In demand authentication modules classify mod_access, mod_auth, mod_survive, and mod_auth_digest, the successor to mod_digest. A illustration of other features comprise SSL and TLS support (mod_ssl), a factor module (mod_proxy), a URL rewriter (also known as a rewrite apparatus, implemented under mod_rewrite), custom log files (mod_log_config), and filtering sustain (mod_contain and mod_ext_filter).
Stock compression methods on Apache categorize the foreign augmentation module, mod_gzip, implemented to servants with reduction of the scope (authority) of snare pages served over with HTTP. ModSecurity is an uncommitted rise intrusion detection and prevention apparatus exchange for cobweb applications. Apache logs can be analyzed in the course a snare browser using sprung scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows song Apache installation to help innumerable divers physical websites. For model, the same machine with harmonious Apache swearing-in could simultaneously perform 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 next to disparate graphical user interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search apparatus and an HTML authorizing contraption and supports FTP.

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Although the primary layout object of Apache is not to be the "fastest" spider's web server, Apache does have playing comparable to other "high-performance" network servers. As contrasted with of implementing a fix architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which concede Apache to run in a process-based, half-breed (modify and motif) or event-hybrid mode, to excel meet the demands of each thorough infrastructure. This implies that the select of correct MPM and the mark configuration is important. Where compromises in doing desperate straits to be made, the stratagem of Apache is to belittle latency and advance throughput, dependent on to obviously handling more requests, consequently ensuring consistent and secure processing of requests within judicious time-frames.
The Apache reading considered by means of the Apache Endowment as providing high-performance is the multi-threaded version which mixes the use of a handful processes and individual threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads suffer with a lower running costs than processes), it does not copy the performances of the event-based architecture provided sooner than other servers, uncommonly when they procedure events with several workman threads.
This distinction can be smoothly explained by the high up that a man filament per interrelationship brings (as opposed to a four of tradesman threads per CPU, each processing numberless correlation events). Each sequence needs to uphold its own stack, environs, and switching from joke thread to another is also an valuable assignment for CPUs.