Parallel processing:

 The operating system that is used to operate, control and manage a parallel computer system is called parallel processing operating system. Any system that has more than one CPU can perform parallel processing, as well as multi-core processors which are commonly found on computers today. Multi-core processors are IC chips that contain two or more processors for better performance, parallel processing is commonly used to perform complex tasks and computations. The parallel execution can be achieved by executing multiple processes on different processors in parallel.

In parallel processing operating system the task of a program that required many calculations is divided into many smaller tasks and these are processed by multiple processors at the same time

   

 

 

Distributed Operating system Book:

A distributed operating system is an operating system that manage a group of independent computers and makes them appear to the users as a single computer

When independent computer are networked together in such a way to work in a co-operative manner then they give rise to a distributed system. In a distributed environment, for performing a task, the computers communicate with each other and perform operations in such a way that the users don not feel that the computations are taking place on more than one machine.

In distributed environment, the resources should be shared; the process should be scheduled on different machines,

Distributed operating system:

A distributed operating system is an operating system that manage a group of independent computers and makes them appear to the users as a single computer

in distributed operating system  several computer systems connected through a single communication channel. Moreover, these systems have their individual processors and memory. These processors communicate through high-speed buses or telephone lines. These individual systems that connect through a single channel are considered as a single unit. We can also call them loosely coupled systems. The individual components or systems of the network are nodes.

Examples of Distributed Operating System

Few examples of a distributed OS are as follows:

AIX operating system for IBM RS/6000 computers.

Solaris operating system for SUN multiprocessor workstations.

Mach/OS is a multitasking and multithreading UNIX compatible operating system.

OSF/1 operating system

Features/Characteristics of Distributed Operating System

1. Resource Sharing The main important feature of this system is that it allows users to share resources. Moreover, they can share resources in a secure and controlled manner. Resources can be of any type. For example, some common resources which are shared can be printers, files, data, storage, web pages, etc.

3. Concurrency It means that several tasks take place at different nodes of the system simultaneously. Moreover, these tasks can also interact with each other. It results in increasing the efficiency of the system.

6. Transparency

It is the most important feature of the system. The main goal of a distributed OS is to hide the fact that the resources are being shared. Furthermore, transparency means that the user should not know that the resources he is using are shared. Moreover, for the user, the system should be a separate individual unit.

Advantages of Distributed OS

The load on the system decreases.

If one system stops it will not affect the other.

The system shares a workload that makes calculations easy.

The size of the system can be set according to requirements.

Disadvantages of Distributed OS

·         The cost for set up is more.

·         Failure of the main system will affect the whole system.

·         Programming is complex.