Operating System and It's Type


Today in this Computer Science Study Material for Gate Based tutorial I will tell you about what is an operating system and what are different types of an operating system.

What is an Operating System ?

Operating System: Operating system works as an interface between user and hardware. Operating System also works as a Resource manager.  It is a control program. It is a system software which provides the environment and platform to application software for their use. It provides support and services to application software.

Operating system is also known as resource allocator because it allocates the required resources such as memory, cpu, I/O, file etc to user process for its execution. 


Types of Operating System


(1)Batch Operating System :  Batch Processing means combining similar types of job in to a batch and executing those batch one after another. This is achieved by putting a list of commands required to start a job and placed these commands in a batch file now this batch file execute as a single program. It is the responsibility of the batch operating system to change the control from one job to another.

 Batch Operating system is a non interactive system it means user does not interacts with program during its execution.

To speed up processing, jobs with similar needs were batched together and were run through the computer as a group. Thus, the programmers would leave their programs with the operator. The operator would sort programs into batches with similar requirements and, as the computer became available, would run each batch. The output from each job would be sent back to the appropriate programmer. A special program monitor manages the execution of each program in batch. Monitor program is always in the main memory and available for the execution


batch operating system


(2) Multiprogramming Operating System : Multi Programming means loading more than one program in to memory and executing them by single cpu ( in case of single processor system) . Number of programs present in main memory at a time is known as degree of multiprogramming.
                     
Main advantage of multiprogramming system is that CPU does not become idle because it always have a process to execute. When CPU finish the execution of one program then it takes the next available program from memory and starts to execute that program.  It means multiprogramming Operating system increase the cpu utilization.


                                                  
operating system note

(3)  Multi Tasking Operating System. : Multi Tasking is the logical extension of multiprogramming system. Some authors says that multiprogramming and multi tasking are same but there is some difference between multiprogramming and multitasking system . Main difference in multi tasking and multi programming is that in case of multitasking system environment may be non preemptive. It means once the cpu is allocated to any process then it may switch to another program without executing it completely , program can be preempted during its execution. Multi tasking system is interactive system.

 A normal Multi programming System does not provide multi user support.


 (4) Time Sharing Operating System: In time sharing system round robin scheduling algorithm is used in which a equal amount of time quantum is shared among all the processes or users ( in case of multiuser system ). Once this time quantum is expired then cpu switch to the next process.

It provide quick response and reduce the cpu idle time. In time sharing system when multiple jobs are executed by the cpu then this switching occurs so frequently that user can interact with each program during its execution.


Time sharing operating system support multi user  environment. Multiuser operating system is an operating system that allow multiple user on different computer or terminals to access single computer system with one operating system. Some problems associated with time sharing system is problem of reliability and problem of data communication.


operating system notes


(5) Real Time System: In real time system there is a rigid time deadline to complete the given task. It is used in specific real time scenario like missile launching, aerospace . It is of two types

(a)    Hard real time system : It is purely deterministic and time constraints System In hard real time system meeting deadline is very important if deadline does not meets then system performance will fails.  Example: Flight control, rocket launching system.

     (b)Soft Real time system: Soft real time system is less restrictive as compare to hard real time system. In soft real time system if the given task dose not complete with in time deadline then it is not so much harmful. For example audio and video etc


Some other types of operating system are MultiProcessor System, Distributed System, Multithreaded System. Which I will discussed later in more detail.

I hope this gate study material for computer science will helps you in understanding the different types of operating system.