Layered View of Operating System | User View | Hardware View

We can categorized view of Operating System:

(i) User View: It various according to the interface being used. User interface with monitor, keyboard, mouse and system unit. They uses for maximize the work that the user is performing. OS provides the services, execution of program, control access to files, access to I/O devices, error detection etc.

(ii) Hardware View: According to hardware view OS acts as resources managers, e.g. allocation of resources, protection of resources etc.

(iii) System View: Operating System is the program most intimately involved with the hardware. It is set of instructions that are executed by the processor.


History of Operating System

First generation(1940’s): The earliest computers had no operating systems. There were no programming languages. Machines of the time were pure mechanical. They introduced Vacuum tubes in first time.

Second generation(1950’s): The routine had improved somewhat with the introduction of punch cards and batch system. They introduced Transistors and Batch Systems. The basic physical layout of batch system:
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Third generation(1960’s): Operating system designer developed concept of multiprogramming as used in spooling batch system. Another feature present in this generation was time-sharing technique, that is a variant of multiprogramming technique. They introduced ICs and Multiprogramming.



Fourth generation(1970’s-present): LSI(large scale integration) circuits, chips, operating system entered in the personal computer and the workstation age. MS-DOS and UNIX were introduced in this stage.They introduced Operating System for Personal Computers.

Real time, Embedded, parallel, Network programming were introduced between 1980-2000. Today's, we have parallel computer architectures(2000-present) and high speed operating systems.

Fifth generation(1990’s-present): In era Operating System for Mobile Computers invented.

What is Operating System?

Operating system provides a basis for application programs and acts as an intermediary between the computer user and the computer hardware, because it is a program that manages a computer’s hardware. we can explore operating systems from two viewpoints: that of the user and that of the system.

From the system’s point of view, it is the program most intimately involved with the hardware, therefore we operating system acts as a resource allocator.


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Operating system allows the compute system in more convenient and efficient resource utilization.


Structure of Computer System

A computer system consists user, application programs (e.g, video games, database system, web browser), system program (e.g., shell, editor, compiler ), operating system and hardware (e.g., CPU, disk memory, I/O devices).
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Where Users and application programs are user end. Utilities and operating system are system . Machine language, micro-architecture, and physical-device are hardware.