• Process

 

A process is basically a program in execution. The execution of a process must progress in a sequential fashion.

 

A process is defined as an entity which represents the basic unit of work to be implemented in the system.

To put it in simple terms, we write our computer programs in a text file and when we execute this program, it becomes a process which performs all the tasks mentioned in the program.

 

When a program is loaded into the memory and it becomes a process, it can be divided into four sections ─ stack, heap, text and data. The following image shows a simplified layout of a process inside main memory −

 

Process Components

S.N. Component & Descr iption

1

Stack

The process Stack contains the temporary data such as method/function parameters, return address and local variables.

 

2

Heap

This is dynamically allocated memory to a process during its run time.

 

3

Text

This includes the current activity represented by the value of Program Counter and the contents of the processor's registers.

 

4

Data

This section contains the global and static variables.

 

• Program

 

A program is a piece of code which may be a single line or millions of lines. A computer program is usually written by a computer programmer in a programming language. For example, here is a simple program written in C programming language −

 

#include <stdio.h>

 

int main() {

printf("Hello, World! \n");

return 0;

}

A computer program is a collection of instructions that performs a specific task when executed by a computer. When we compare a program with a process, we can conclude that a process is a dynamic instance of a computer program.

 

A part of a computer program that performs a well-defined task is known as an algorithm. A collection of computer programs, libraries and related data are referred to as a software.