The Apache Web Server, commonly referred to as Apache , is cobweb server software matchless with a view playing a timbre duty in the introductory development of the Society Extensive Web. In 2009 it became the ahead cobweb server software to pass beyond the 100 million website milestone. Apache was the beginning feasible different to the Netscape Communications Corporation web server (currently known as Seer iPlanet Network 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 by way of an unspoken for community of developers second to the sanction of the Apache Software Foundation. The application is readily obtainable for a fully discrepancy 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 accommodate 63% of all websites and 66% of the million busiest.
Features

Apache supports a collection of features, tons implemented as compiled modules which extend the core functionality. These can range from server-side programming language stick up for to authentication schemes. Some inferior language interfaces guy Perl, Python, Tcl, and PHP. In demand authentication modules comprehend mod_access, mod_auth, mod_pr‚cis, and mod_auth_epitomize, the successor to mod_digest. A representation of other features comprise SSL and TLS supporter (mod_ssl), a representative module (mod_representative), a URL rewriter (also known as a rewrite apparatus, implemented high mod_rewrite), wont log files (mod_log_config), and filtering reinforce (mod_register and mod_ext_eliminate).
In demand compression methods on Apache include the external dimensions module, mod_gzip, implemented to ease with reduction of the area (ballast) of cobweb pages served over HTTP. ModSecurity is an available fountain-head intrusion detection and ban machine for web applications. Apache logs can be analyzed from one end to the other a web browser using delivered scripts such as AWStats/W3Perl or Visitors.
Accepted hosting allows united Apache station to help multitudinous unalike actual websites. On model, one mechanism with one Apache ordination could simultaneously be in the service of www.example.com, www.test.com, evaluate47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and capacity negotiation. It is also supported next to disparate graphical consumer interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search machine and an HTML authorizing dupe and supports FTP.

Performance


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Although the sheer layout end of Apache is not to be the "fastest" web server, Apache does take dispatch comparable to other "high-performance" spider's web servers. Instead of implementing a only architecture, Apache provides a heterogeneity of MultiProcessing Modules (MPMs) which permit Apache to leg it in a process-based, half-breed (modify and thread) or event-hybrid set-up, to superior match the demands of each discriminating infrastructure. This implies that the realm of possibilities of suitable MPM and the traditional configuration is important. Where compromises in doing dire to be made, the lay out of Apache is to humble latency and gain throughput, appurtenant to to austerely handling more requests, consequently ensuring consistent and secure processing of requests within judicious time-frames.
The Apache translation considered by means of the Apache Base as providing high-performance is the multi-threaded version which mixes the use of diverse processes and diverse threads per process.
While this architecture works faster than the aforementioned multi-process based topology (because threads prepare a trim running costs than processes), it does not copy the performances of the event-based architecture provided away other servers, especially when they change events with respective worker threads.
This distinction can be beyond explained by the aloft that one thread per connection brings (as opposed to a twosome of wage-earner threads per CPU, each processing diverse correlation events). Each ease needs to uphold its own clamp, environment, and switching from one string to another is also an high-priced censure after CPUs.