The Httpd Web Server, commonly referred to as Apache , is web server software renowned for the purpose playing a key duty in the commencing success of the Set Wide Web. In 2009 it became the first cobweb server software to outshine the 100 million website milestone. Apache was the chief feasible different to the Netscape Communications Corporation network server (currently known as Seer iPlanet Entanglement Server), and has since evolved to challenge other entanglement servers in terms of functionality and performance. Typically Apache is hop to it on a Unix-like operating system.
Apache is developed and maintained during an open community of developers underneath the approval of the Apache Software Foundation. The germaneness is available on a deviating variety 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 Allow, 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 variety of features, tons implemented as compiled modules which extend the core functionality. These can class from server-side programming communication stick up for to authentication schemes. Some conventional lingua franca interfaces guy Perl, Python, Tcl, and PHP. Trendy authentication modules include mod_access, mod_auth, mod_pr‚cis, and mod_auth_epitomize, the successor to mod_digest. A illustration of other features include SSL and TLS supporter (mod_ssl), a proxy module (mod_agent), a URL rewriter (also known as a rewrite engine, implemented high mod_rewrite), custom log files (mod_log_config), and filtering support (mod_contain and mod_ext_eliminate).
Sought-after compression methods on Apache allow for the superficial augmentation module, mod_gzip, implemented to servants with reduction of the size (strain) of snare pages served during the course of HTTP. ModSecurity is an available rise intrusion detection and enjoining apparatus in the direction of cobweb applications. Apache logs can be analyzed help of a entanglement browser using delivered scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows united Apache consecration to fulfil innumerable different physical websites. Allowing for regarding example, the same gizmo with one Apache installation could simultaneously favourable to www.example.com, www.test.com, evaluate47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and constituents negotiation. It is also supported near sundry graphical operator interfaces (GUIs).
It supports watchword authentication and digital certificate authentication. Apache has a built in search locomotive and an HTML authorizing gimmick and supports FTP.

Performance


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Although the main cabal goal of Apache is not to be the "fastest" trap server, Apache does take playing comparable to other "high-performance" trap servers. In lieu of of implementing a only architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which deduct Apache to hump it in a process-based, combination (process and thread) or event-hybrid mode, to excel match the demands of each thorough infrastructure. This implies that the realm of possibilities of chasten MPM and the nullify configuration is important. Where compromises in dispatch dire to be made, the stratagem of Apache is to slash latency and advance throughput, appurtenant to to austerely handling more requests, in which case ensuring consistent and honourable processing of requests within tenable time-frames.
The Apache version considered not later than the Apache Fundamental as providing high-performance is the multi-threaded version which mixes the use of a handful processes and various threads per process.
While this architecture works faster than the too soon multi-process based topology (because threads prepare a trim running costs than processes), it does not accord the performances of the event-based architecture provided away other servers, especially when they procedure events with several hand threads.
This inequality can be smoothly explained on the aloft that undivided line per connection brings (as opposed to a four of tradesman threads per CPU, each processing many correlation events). Each ease needs to uphold its own load, habitat, and switching from one plot to another is also an expensive censure in compensation CPUs.