Types of Operating System Tutorial

What is an Operating System ?

Operating System is system software that works as an interface between user and hardware. Operating System also works as a Resource manager. It is a control program.

Operating System is system software that provides the environment and platform to application software for their use.

It provides support and services to application software.The operating system is also known as a resource allocator because it allocates the required resources such as Memory, CPU, I/O, file, etc., to the user process for its execution.

Types of Operating System

In this section we will study about types of operating system with diagrams or how many types of operating system are there? Operating can be classified in following ways –

 

In a simple Batch Processing environment, we combine similar types of jobs into 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 executes as a single program.

 

This is the responsibility of the batch operating system to change the control from one job to another automatically during the execution.

 

Batch Operating system is a non-interactive system. It means the user does not interact with the 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 particular program monitor manages the execution of each program in batch. Monitor Program is always in the main memory and available for the execution

Multi Programming means loading more than one program into memory and executing them by a single CPU ( in the case of a single processor system). A number of programs present in main memory at a time are known as Degree of Multiprogramming.

 

The main advantage of a multiprogramming system is that the CPU does not become idle because it always has a process to execute.

 

When the CPU finishes 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 increases CPU Utilization.

 

 

Multitasking is the logical extension of a multiprogramming system. Some authors say that multiprogramming and multitasking are the same, but there is some difference between multiprogramming and multitasking systems.

 

The main difference between multitasking and multi programming is that in the case of a multitasking system, the environment may be preemptive. It means once the CPU is allocated to any process, then it may switch to another program without executing it thoroughly; the program can be preempted during its execution.

 

A multitasking system is an interactive system. A normal Multiprogramming System does not provide multiuser support.

In time sharing system Overall CPU time is shared among the  each process or user. Round Robin CPU Scheduling Algorithm is used in time sharing operating system. A  fixed time quantum is shared among all the processes or users( in case of multiuser syste

m ). 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.

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

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.

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

Next Tutorial – Process Management in OS