boggerpiya: December 2021

1.operating system:

2.What is operating system??

The system software that manage computer hardware ,software resources ,and provides common services for computer program. operating system is system software .An operating system is a program that, after being initially loaded into the computer by a boot program , manage all of the other application program in a computer.

1.Batch processing operating system: A job which has predefined sequence of commands, program and data as a single unit. Users had no direct interface with the system , and job execution was done in a batch system and users have to prepare a job separately to execute it. The operating system keeps a number a jobs in memory and executes them without any manual information , jobs are processed in order of submission. First come first served fashion..

2.Multitasking or Time sharing operating system:

In time sharing operating system allows the user to performs more than one task at a time, each task getting the same amount of time to execute. The operating system performs time sharing through CPU scheduling and multiprogramming. It is the division of CPU time for each process when more than one task are given by the user..

3.Distributed operating system:

A distributed operating system is system software , over a collection of independent, networked, communicating ,and physically separate computational nodes. Distributed system use many central processors to serve multiple real -time applications and users. As a result, data processing jobs are distributed between the processors..

4.Networking operating system:

A networking operating system is a computer operating system that is designed primarily to support workstations, personal computer and in some instances, older terminals that are connected on a local area network. The role of the NOS is to than provide basic network services and features that support multiple input requests simultaneously in multiuser environment..

5.Real time operating system: A real time operating system for real-time applications that processes data and events that have critically defined time constraints. A real time operating system time interval to process and respond to inputs is very small. Event driven systems switch between tasks based on their priorities, while time sharing systems switch the task based on clock interrupt ..

3.Structure of operating system

An operating system is a construct that allows the user application programs to interact with the system hardware.

1.simple structure:

These started as small system and rapidly expanded much further than their scope . A common example of this is MS-DOS.it was designed simply for a niche amount for people .An image to illustrate the structure of MS-DOS is as follows.

An image to illustrate the structure of MS-DOS is as follows.

MS-DOS

2.Layered structure of operating system:

In this ,the bottom layer is the hardware and the topmost layer is the user interface.

Each upper layer is built on the bottom layer. All the layers hide some structure, operations etc. from their upper layers .One problem with the layered structure is that each layer needs to be carefully defined. This is necessary because the upper layers can only use the functionalities of the layers below them.

4. Example of operating system: