A Distributed computing is a model of computation that is firmly related to Distributed Systems, refers to as multiple computer systems located at different places linked together over a network and use to solve higher level computation without having to use an expensive supercomputer. Distributed system is called, When collection of various computers seems a single coherent system to its client, then it is called distributed system.
According to the definitions; All the computers are tied together in a network either a Local Area Network (LAN) or Wide Area Network (WAN), communicating with each other so that different portions of a Distributed applications run on different computers from any geographical location. Every node on the Distributed computing is autonomous machines (do not physically share memory or processors but thereby sharing resources such as printers and databases).
Distributed Systems have broken down into two parts: the front end and the back end. The front end, the part of the application that the user interacts with to determine what information she wants to examine and how to organise it, runs on the user's computer. The back end, the part of the application that finds and sorts the requested information, runs on a central computer somewhere else. This type of distributed computing also referred to as "client-server architecture," splits up the functioning of applications across some separate computers.
Grid computing is a based on distributed architecture and is the form of "distributed computing" or "peer-to-peer computing"that involving large numbers of computers physically connected to solve a complex problem.
Standalone applications are traditional applications(or 3-tier old systems) that run on a single system; distributed applications run on multiple systems simultaneously. Traditional applications need to be installed on every system and make it hard to maintain. However, In Distributed computing, applications run on both simultaneously. With distributed computing, if a workstation that goes down, another workstation can resume the jobs.
The advantages of distributed computing increased the speed with “absolute performance” and lower cost with more reliability than a non-distributed system. It is currently quite popular, and many businesses are converting to it as we speak.
Extremely well-known example of distributed systems and applications of distributed computing used in SETI@Home project of the University of California Berkley, Telecommunication networks, Telephone networks and cellular networks, Computer networks such as the Internet, Wireless sensor networks, Routing algorithms.