Distributed system
In computer science, a distributed system is an application that consists of components running on different computers concurrently. These components communicate via some telecommunications network. Together, they provide some service to users.
An example of a distributed system is the World Wide Web. As you are reading a web page, you are actually using a distributed system.
As you are browsing the web, your web browser running on your own computer communicates with different web servers that provide web pages. Possibly, your browser uses a proxy server to access the web contents stored on web servers faster and more securely. To find these servers, it also uses the DNS system, which is itself a distributed system running on yet another set of computers. Your web browser communicates with all of these servers over the Internet, via a system of routers which are themselves part of a large distributed routing system using the BGP protocol.
Together, web servers, proxies, and browsers, DNS servers and Internet routers comprise a very-large-scale distributed system that provides access to information (web pages and other content) that is spread all over the world.
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