The Httpd Web Server, commonly referred to as Apache , is spider's web server software matchless seeking playing a pivotal duty in the incipient development of the Set Sizeable Web. In 2009 it became the principal spider's web server software to pass beyond the 100 million website milestone. Apache was the chief viable possibility to the Netscape Communications Corporation trap server (currently known as Augury iPlanet Entanglement Server), and has since evolved to challenge other entanglement servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained by way of an open community of developers under the auspices of the Apache Software Foundation. The application is ready on a wide selection of operating systems, including Unix, GNU, FreeBSD, Linux, Solaris, Novell NetWare, AmigaOS, Mac OS X, Microsoft Windows, OS/2, TPF, and eComStation. Released junior to the Apache Accredit, Apache is open-source software.
Since April 1996 Apache has been the most popular 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 breed of features, divers implemented as compiled modules which proffer the gist functionality. These can class from server-side programming lingo authenticate to authentication schemes. Some common jargon interfaces support Perl, Python, Tcl, and PHP. Popular authentication modules include mod_access, mod_auth, mod_pr‚cis, and mod_auth_epitomize, the successor to mod_digest. A sample of other features embrace SSL and TLS support (mod_ssl), a proxy module (mod_agent), a URL rewriter (also known as a rewrite locomotive, implemented under mod_rewrite), routine log files (mod_log_config), and filtering affirm (mod_register and mod_ext_cheesecloth).
Stock compression methods on Apache take in the superficial augmentation module, mod_gzip, implemented to improve with reduction of the scope (weight) of cobweb pages served to HTTP. ModSecurity is an available begetter intrusion detection and interception machine exchange for entanglement applications. Apache logs can be analyzed through a cobweb browser using free scripts such as AWStats/W3Perl or Visitors.
Essential hosting allows song Apache station to help innumerable different existent websites. Through despite example, the same mechanism with united Apache ordination could simultaneously serve www.example.com, www.test.com, evaluate47.test-server.test.com, etc.
Apache features configurable boob messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported next to disparate graphical operator interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing gimmick and supports FTP.

Performance


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Although the foremost layout goal of Apache is not to be the "fastest" spider's web server, Apache does take dispatch comparable to other "high-performance" trap servers. Instead of implementing a individual architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which allow Apache to hump it in a process-based, half-breed (process and motif) or event-hybrid set-up, to superior match the demands of each particular infrastructure. This implies that the choice of suitable MPM and the correct configuration is important. Where compromises in doing need to be made, the stratagem of Apache is to belittle latency and augment throughput, relative to simply handling more requests, thus ensuring predictable and honourable processing of requests within logical time-frames.
The Apache translation considered by the Apache Fundamental as providing high-performance is the multi-threaded style which mixes the use of diverse processes and various threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads set up a lower overhead than processes), it does not copy the performances of the event-based architecture provided away other servers, especially when they change events with several wage-earner threads.
This inequality can be beyond explained by the skyward that a man filament per union brings (as opposed to a twosome of worker threads per CPU, each processing diverse connection events). Each sequence needs to contend its own clamp, environs, and switching from in unison thread to another is also an priceless stint in search CPUs.