What is Process / Task in operating system

Process: 

A process is an instance of a program running in a computer. It is close in meaning to task, a term used in some operating systems. Processes are one of the oldest and most important abstractions that operating systems provide. They turn a single CPU into multiple virtual CPUs. Without the process abstraction, modern computing could not exist.

Concepts-Process:

Operating system is a collection of programs to manage system resources, processor and memory, input and output device and file system. The operating system allocate resources to different processes based on certain policy, decide how long these resources and deal locate it.

Processor management is concerned with the management of physical processors (CPU).  A process is basically a programmed while it is being executed. A process is a running program with some specific tasks to do. Multiprogramming systems explicitly allow multiple processes to exist at any given time, where only one is using the CPU at any given moment, while the remaining processes are performing I/O or are waiting.

The process manager is of the four major parts of the operating system. It implements the process abstraction. It does this by creating a model for the way the process uses CPU and any system resources. Much of the complexity of the operating system stems from the need for multiple processes to share the hardware at the same time. As a consequence of this goal, the process manager implements CPU sharing (called scheduling), process synchronization mechanisms, and a deadlock strategy. In addition, the process manager implements part of the operating system's protection and security.

For example: In operating system command interpreter is also process, performing the task of listening to whatever is typed on a terminal. Every time we run a commend interpreter. When a process is created, it requires several resources such as CPU time for programmed. When CPU executes a programmed or command, a process is created. When one process stops running because it has taken its share of CPU time, another process starts.

            When process is temporary suspended, information about it is stored in a memory location so that it’s execution could start from the same location where from it was suspended. In many as all the information about each process is stored in a process table. This process table is called as process control block.(PCB).

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