Distributed Systems
A distributed computer system consists of multiple software components on multiple computers, but which run as a single system. The computers in a distributed system can be physically close together and connected by a local network, or they can be geographically distant and connected by a wide area network. A distributed system can consist of any number of possible configurations, such as mainframes, personal computers, workstations, minicomputers, and so on. The goal of distributed computing is to make such a network operate as a single computer.
Distributed systems offer many benefits over centralized systems, including the following:
Scalability
The system can easily be expanded by adding as many machines as needed.
Redundancy
Several machines can provide the same services, so if one is unavailable, the work does not stop. Additionally, as many smaller machines can be used, this redundancy is not necessarily expensive.
Distributed computing systems can operate on hardware that is provided by many vendors, and use a variety of standard-based software components. Such systems are independent of the underlying software. They can run on various operating systems, and use various communication protocols. Some hardware might use UNIX or Linux as the operating system, while the other hardware might use Windows operating systems. For intermachine communications, this hardware can use SNA or TCP/IP on Ethernet or Token Ring.