Classification or Evolution of Operating System

Classification of Operating System (Generation of OS/Evolution of OS):

In computer system Operating system is a main component, and there are following type of OS .

    1.Bare Machine:-

         In this type of machine there is no concept of os, and user can not interact directly with the machine they can submit their job though the programmer. Then programmer prepare environment for specific program.

Punch card and paper tape are use as input device and Line printer are use as a output device.                                                                

Example:

If there is need of execution of c program then programmer prepare the c programming environment .

Drawback of Bare Machine:

• Setup Time:    setup time is too large if failure occurs then whole setup is restarted from starting.

• Time Consuming:   Takes much time to execute the program.

• Scheduling

2. Batch Operating System:

In the Batch Machine Operating System we prepare batch (Group) of similar jobs, and programmer execute the one batch at a time. It maintains the batch of similar behaviour of jobs.

Batch System

  In batch processing user can not directly interact with computer machine. He submits the job to computer programmer and programmer takes one job and produces the batches of similar behavior jobs.

3. Spool :  

It is a concept of 2nd Generations Operating System, like Batch machine Operating System.

"Spooling is process of buffering". 

It stands for Simultaneous Peripheral Operation Online. It use to improve the speed mismatch between the devices, by which we can buffer the input and output process.

4. Multiprogramming:

multi programming is a technique by which we can increase CPU utilization by organizing the job In such way, CPU has always one job to execute.

"At the same time one program is executed but switching is very fast".

Multi Programming Operating System Diagram

Multi-Programming means execution of multiple-programs at the same time by context switching of the processes.

5. Multi Processing Operating System:

"Multiprocessor Operating System enable to support and utilized multiple processor on a single machine".

It is Divided into two part...

1.Uniprocessing

2. MultiProcessing

Uniprocessing:  

"computer system with one processor is called Uniprocessing" .

Uniprocessor system block diagram

Multi Processing:

"A computer system with two or more processors is called Multi processor system".

Multiprocessing operating systems are categories in two parts 

(A). Symmetric Multiprocessing (Tightly coupled system):

All processor used the shared memory. And each processor work independently.

(B). Asymmetric Multiprocessing (Loosely coupled system) :

In this system each processor have their own memory.

In Asymmetric multiprocessing there is master slave relationship between the processor that is one processor work as a master processor and remaining are all work as slave processor.

6. Multi Tasking or Time Sharing System:

Multi Tasking or Time Sharing System is a logical extension of Multiprogramming in which we divide the processing time into time slat and these time slat are assign to their client machine, and switching between machine is a round robin fashion.

7. Network Operating System:

There are two type of Network OS.

• Client Server OS
• Distributed OS

Client Server Operating System:

It is specially design to serve the client server architecture in which one of the machine is work as master machine and others are follows there instruction called slave machine.

E.g:    

windows NT, 2008,2003 and Unix

Distributed Operating System:

       Distributed operating system are scatted is separate geographical location and connected to an interconnected network. In distributed OS all the the machine are shared their resources(H/W as well as S/W resource) between all other machines which are in that network.

Advantage:

• Less cost
• Resource utilization

Disadvantage:

• Performance decrease
• Security less

8. Real Time Operating System:

It provide Quick response time by which a program executed in certain time period, secondary coherence of such OS to provide user interface and resource utilization.

These type of OS are used in ,

Missile launching,

Air traffic controlling,

Medical imaging system etc.

There are two type of Real Time Operating System.

1. Soft Real Time OS
2. Hard Real Time OS

1. Soft Real Time OS(SRT-OS):

In this types of OS if certain deadline are not meet than OS continuous there execution with degraded performance.

E.g:   Video, virtual reality system, video buffering

2. Hard Real Time OS(HRT-OS):

In this OS if certain deadlines are failed continuous there execution.

Ex: 

Missile launching

Air Traffic Controlling etc.