Introduction to Parallel/ distributed computing, Grid Computing and Cloud computing

What are Parallel and Distributed Computing?

Both terms Parallel Computing and Distributed Computing have a lot of overlaps and there is no clear distinction between them. The same system can be characterized both as Parallel and Distributed.

In general Parallel Computing/ Distributed Computing is study of Parallel/ Distributed Systems. Parallel Systems refer Networked Systems where individual computer systems are distributed within some geographical area. And a distributed System is a system whose components are located on different networked computers, in which computers communicate by message passing.
In broad manner Distributed Computing refers to the use of distributed systems to solve computational problems.In distributed computing, a computational problem is divided into many tasks, each task is solved bu one or more computers which communicate with each other via message passing.

while there is no clear cut distinction between parallel and distributed systems we can roughly make distinction between them
  • In Parallel Computing all processors may have access to a shared memory to exchange information among processors.
  • In Distributed Computing each processor has its own private memory.Information is exchanged among the processors by message passing.

Examples of Distributed/ Parallel Computing:

Followings are the example of distributed systems and application of distributed computing:
  • Telephone and cellular networks, computer networks as internet, wireless sensor networks, routing algorithms.
  • Distributed database and distributed database management system and network file system.
  • Distributed information processing systems such as airline reservation systems.
  • Real time processing control such as missile control systems, aircraft control systems.
  • Parallel computing such as scientific computing, cluster computing and grid computing.

What is Grid Computing?

A computing grid interconnects resources such as high performance computers, scientific databases etc each of which is autonomous.The Globus project ( defined grid computing as: "An infrastructure that enables the integrated, collaborative use of high-end computers, networks, databases, and scientific instruments owned and managed by multiple organizations". In an overview we can define Grid Computing as it is a facility, infrastructure that put together multiple computer systems from different domains to reach a common goal to solve a single task.

In the Grid Computing the grids may be any distributed system with large numbers of files. Grid Computers are more heterogeneous and geographically dispersed. The numbers of systems in grid mar vary from small to large. A small Grid may be like a network of computer workstations within a corporation and a large grid my be something like public collaborations across many companies and networks.

What is Cloud Computing?

The best definition from the dictionary."The practice of using a network of remote servers hosted on the internet to store, manage and process data, rather than a local server or a personal computer."
Microsoft defines Cloud Computing as "cloud computing is the delivery of computing services-servers,storage, databases, networking, software,analytics, intelligence and more- over the Internet
(the cloud) to offer faster innovation, flexible resource and economies of scale." You typically pay only for cloud services you use helping lower your operating costs, run your infrastructure more efficiently and scale as your business needs change.