Title Unit 1.pdf ✅

Unit – 1 Introduction Software is a collection of instructions, data, or computer programs that are used to run machines and carry out particular activities. A device’s running programs, scripts, and applications are collectively referred to as “software” in this context. Types of s/w Operating System System a group of components or subsystems that integrate and function together in order to achieve a specific goal. Definition of OS • An operating system is a program that acts as an interface between the software and the computer hardware. • It is an integrated set of specialized programs used to manage overall resources and operations of the computer.
• It is a specialized software that controls and monitors the execution of all other programs that reside in the computer, including application programs and other system software. Objectives of operating system: • To make the computer system convenient to use in an efficient manner. • To hide the details of the hardware resources from the users. • To provide users a convenient interface to use the computer system. • To act as an intermediary between the hardware and its users, making it easier for the users to access and use other resources. • To manage the resources of a computer system. • To keep track of who is using which resource, granting resource requests, and mediating conflicting requests from different programs and users. • To provide efficient and fair sharing of resources among users and programs.
Functions of Operating System: 1. Process Management It includes various tasks like scheduling and termination of the process. It is done with the help of CPU Scheduling algorithms. 2. Memory Management Refers to the management of primary memory. The operating system has to keep track of how much memory has been used and by whom. It has to decide which process needs memory space and how much. OS also has to allocate and deallocate the memory space. 3. CPU Scheduling CPU scheduling refers to the switching between processes that are being executed. It forms the basis of multi-programed systems. This switching ensures that CPU utilization is maximized so that the computer is more productive. 4. File Management The process and act of creating an organized structure in which you store information for easy retrieval. 5. Security Privacy is also provided by the Operating system using passwords so that unauthorized applications can’t access programs or data. For example, Windows uses Kerberos authentication to prevent unauthorized access to data. 6. Coordination Between Other Software and Users − Coordination and assignment of compilers, interpreters, assemblers, and other software to the various users of the computer systems.
Evolution of operating system Overview In today's world, we can see that a user of the computer directly interacts with the computer. But in the past years, the users were not able to directly interact with the computer hardware. Initially, the users used to provide the instructions and the computer had to follow them. After some evolution, the users used to prepare their instructions in the form of jobs on an off-line device like punch cards and submit them to the computer operator. After that, users were able to communicate with the operating systems with the help of software called command-line interface or CLI. Nowadays, with the development of Graphical User Interface (in modern operating systems), the user experience is more convenient. Evolution of Operating System - OS Generations Before learning about the evolution of operating systems, let us first get a brief understanding of operating systems. An Operating System is nothing but a software program that acts as an interface between the hardware, the application software, and the users. The main aim of an operating system is to manage all the computer resources, security, file systems, etc. So, we can simply say that the operating system gives a platform to the application software and other system software to perform their task. Refer to the diagram below to understand the value and working of the operating system.