OPERATING SYSTEM: AN OVERVIEW syst… · Multiprogramming Operating System: A multiprogramming operating system is a system that allows more than one active user program to be stored

Ms. Ima Hussain

Visiting Faculty

Department of Computer Application

Gautam Buddha Mahila College, Gaya

OPERATING SYSTEM:

AN OVERVIEW

OPERATING SYSTEM :

An Operating System (OS) is a collection of programs that acts as an interface

between a user of a computer and the computer hardware.

The purpose of an operating system is to provide an environment in which a

user may execute the programs.

The Main Resource is the computer hardware in the form of processors,

storage, input/output devices, communication devices, and data.

02-May-20Ima Hussain

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User 1 User 2 User 3 User n

Application Programs

Operating System

Computer Hardware

Abstract View of Components of a Computer System02-May-20Ima Hussain

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MAIN FUNCTION OF AN OPERATING SYSTEM:

• Process Management

• Memory Management

• Secondary Storage Management

• I/O Management

• File Management

• Protection

• Networking Management

• Command Interpretation


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OPERATING SYSTEM

Process Management

Memory Management

File Management

Protection and Security

User Interface

I/O Management

Communication

Management

Networking

Secondary Storage


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Types of the Operating System:

• Batch Processing Operating System

• Time Sharing /Multitasking Operating System

• Multiprogramming Operating System

• Multiprocessing Operating System

• Network Operating System

• Distributed Operating System

• Real Time Operating System(RTOS)


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Batch Operating System:

• User Submits their jobs to the central place/operator where similar jobs are collected

into a batch.

• Operator sort jobs as a deck of punch cards into batch with similar needs.

• In this case, has no interaction with the job during its processing and the

computer’s response time is the turnaround time-the time from submission of the

job until execution is complete .

• Example: FORTAN batch, Cobol batch etc.


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Operator

CPUJob 7

Job3

Job2

Job 5

Job 1

Job 4

O.S

User

Program

Batch Operating System

Job 1

Job 2

Job n

Job 3

Multitasking Or Time Sharing Operating System:

❖ Multitasking is also known as multiprogramming with time sharing operating system.

❖ At one instance of time,only one process will run.But the speed is so high that it gives an illusion that all processes

are running together.

❖ The task in multitasking may refer to multiple threads of the some program.

❖ The main idea is better response time and executing multiple process together.

❖ In this approach time quantum is fixed.


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MULTITASKING OR TIME SHARING OPERATING SYSTEM:

WORD

E-MAIL

BROWSER

OPERATING

SYSTEMCPU


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Multiprogramming Operating System:

❖ A multiprogramming operating system is a system that allows more than one active

user program to be stored in main memory simultaneously.

❖ If running process perform I/O or some other event which do not require CPU then

instead of sitting idle, CPU make a context switch and picks some other process and

this idea will continue.

❖ In Multiprogramming, CPU never sit idle unless there is no process ready to execute

or at the time of context switch.

❖ It has a high CPU utilization and less waiting time and response time.

❖ Main memory management is required all the time and memory fragmentation will

also happen.


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Multiprocessing Operating Sytem :

• A multiprocessing system is a computer hardware configuration that includes more than one

independent processing unit.

CPU 2CPU 1 CPU n

MEMORY


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In Multiprocessing operating system ,different process may run at the same time because of multiple CPU.

Therefore, True Parallel Execution happens.

Advantages of Multiprocessing:1. It increased the throughput(per unit time execution of process)

2. It increased the reliability.

3. It has a better efficiency and under the cost saving scheme.

Disadvantages of Multiprocessing:1. It has a complex structure used in major scientific or commercial applications.

2. Main memory should be large enough.


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Distributed Operating System:

➢ A distributed operating system consists of a number of computers that are connected and managed so that

they automatically share the job processing load among the constituent computers, or separate the job load

as appropriate particularly configured processors.

➢ The networked and distributed computing environments and their respective operating system are

designed with more complex functional capabilities.

➢ In a network operating system ,the users are aware of the existence of multiple computers and can log in to

remote machines and copy files from one machine to another.Each machine runs its own local operating

system and has its own user.

➢ A distributed operating system, in contrast, is one that appears to its users as a traditional uniprocessor

system ,even though it is actually composed of multiple processors. In true distributed system,users should

not be aware of where their programs are being run or where their files are located; that should all be

handled automatically and efficiently by the operating system.


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Real Time Operating System:

• Real Time Operating system are designed to service those applications where response time is

of the essence in order to prevent error , misrepresentation or even disaster.

• Example of real time operating system are those which handle airlines reservation, machine

tool control and monitoring of a nuclear power station.

• A RTOS has very little user-interface capability, and no end-user utilities.

• A very important part of an RTOS is managing resources of the computer so that a particular

operation executes in precisely the same amount of time every time it occurs.

• The RTOS are used to control machinery, scientific instruments and industrial system.


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References:

1. Madnick and Donovan, Operating Systems – Concepts and design, McGraw-Hill Intl.

Education

2. Milan Milenkovic, Operating Systems, Concepts and Design, TMGH,2000.

3. D.M.Dhamdhere, Operating Systems, A concept-based approach,TMGH,2002

4. Abraham Silberschatz and James L, Operating System Concepts. Peterson, Addition

Wesley Publishing Company.

5. Harvay M.Deital, Introduction to Operating System, Addition Wesley Publication

Company.

6. Andrew S.Tanenbaum, Operating System Design and Implementation, PHI.


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OPERATING SYSTEM: AN OVERVIEW syst… · Multiprogramming Operating System: A multiprogramming operating system is a system that allows more than one active user program to be stored

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