Some of the most widely used different types of operating systems are:
- Simple Batch System
- Multiprogramming Batch System
- Multiprocessor System
- Desktop System
- Distributed Operating System
- Clustered System
- Realtime Operating System
- Handheld System
Simple Batch Systems
In this type of OS, there is no direct interaction between the user and the computer.
The user has to submit a job to the computer operator. Then the computer operator places a batch of several jobs on an input device. Jobs are batched together by requirement. Then a special program, the monitor, manages the execution of each program in that batch. The monitor is always in the main memory and available for execution of the program.
- Multiple users can share this operating systems.
- The idle time for simple batch system is very less.
- Managing large work repeatedly in batch systems becomes easy.
- The computer operators should be well known about the batch systems.
- These systems are very hard to debug.
- Sometimes it is costly.
- The other jobs need to wait for an unknown period of time if any job fails.
In this types the operating systems picks up and begins to execute one of the jobs from the memory. If any of this job needs an I/O operation then the operating system switches to another job (CPU and OS are always busy). Jobs in the memory are always less than the number of jobs on the disk. If several jobs are ready to run at the same time, then the OS chooses the job to run through the process of CPU Scheduling. In Non-multiprogrammed systems, there are moments when CPU becomes idle and does not do any work. Where as in Multiprogramming system, CPU(Central Processing Unit) will never be idle and keeps on processing the jobs.
- CPU is active all the time and never become idle.
- The system looks to be fast as all the tasks runs in parallel.
- Short time jobs are completed faster compared to long time jobs.
- Multiprogramming systems supports multiple users.
- Resources are used efficiently.
- It becomes difficult to program a system because of complicated schedule handling.
- Tracking all tasks/processes is difficult to handle.
- Due to high load of tasks, long time jobs have to wait for a long time.
Time-Sharing Operating Systems
Each task is given some time to execute, so that all the tasks work smoothly. Each user gets time of CPU as they use single system. These systems are also known as Multitasking Systems. The task can be from single user or from different users also. The time that each task gets to execute is called quantum. After this time interval is over OS switches over to next task.
Advantages of Time-Sharing OS:
- Each task gets an equal opportunity.
- Chances of duplication of software is less.
- Idle time of CPU can be reduced.
Disadvantages of Time-Sharing OS:
- Reliability problem.
- One must have to take care of security and integrity of user programs and data.
- Data communication problem.
Distributed Operating System
These types of operating systems is a recent advancement in the world of computer technology. These are being widely accepted all-over the world and, that too, with a great pace. Different autonomous interconnected computers communicate with each other using a shared communication network. Independent systems possess their own memory unit and CPU. These are referred as a loosely coupled system or distributed system. This system’s processors differ in size and function. The major benefit of working with these types of operating system is that it is always possible that one user can access the files or software which are not actually present on their system but on some other system connected within this network i.e., remote access is enabled within the devices connected in that network. Different types of distributed operating system are:
- Client-Server Systems
- Peer-to-Peer Systems
Advantages of Distributed Operating System:
- Failure of one will not affect the other network communication, as all the systems are independent from each other.
- Electronic mail increases the data exchange speed.
- Since resources are being shared, computation is highly fast and durable.
- Load on host computer becomes less.
- Delay in data processing reduces.
Disadvantages of Distributed Operating System:
- Failure in the main network will stop the entire communication.
- To establish distributed systems the languages which are used are not well defined yet.
- These types of systems are not readily available as they are very costly.
In parallel processing the task/job is divided into different sub tasks and then these sub tasks are distributed to the processors available in the system. It requires more than one processer(multiple processors) to complete the task and all the processors work simultaneously. It completes the task in very less time.
All the processors in the parallel processing are tightly coupled and are present in one casing. All processors in a parallel processing system should work on same operating system. As the tasks are initiated and stored in secondary storage devices, all the processers share a common secondary storage devices(hard disk…).
The user interaction with the system does not make him feel that he/she is a multiprocessor system and they feel like using a single processor system.
Advantages of parallel processing:
- The maintenance cost is low as the components are commercially available.
- If any one of the processor fails then the tasks are rescheduled to another processor for execution.
- If the need of computing is increased then the no of processors are also increased.
- Increase in no of processors will increase the throughput of the system.
A Real time operating system(RTOS) is subjected to work in real time i.e. the output is produced within a given time or the system should meet the specified deadline.
Example: real time monitors, flight control system, radars etc…
Types of real time systems based on timing constraints:
Hard real time system
A hard real time operating system will complete the tasks in the given time. Example: Flight controller system.
Soft real time system
Real-time operating systems that only guarantees a maximum of the time, i.e. the critical task will get priority over the other tasks, but no guarantee of completing it in pre defined time. These systems are referred to as Soft Real-Time Operating Systems.
Example: Telephone switches.
References: Operating System Concepts
Frequently Asked Questions
What are the different types of operating systems?
Simple Batch System.
Multiprogramming Batch System.
Distributed Operating System.
Realtime Operating System.
What is simple batch system?
In this type of OS, there is no direct interaction between the user and the computer. The user has to submit a job to the computer operator. Then the computer operator places a batch of several jobs on an input device.
What is Time-Sharing Operating Systems?
Each task is given some time to execute, so that all the tasks work smoothly. Each user gets time of CPU as they use single system. These systems are also known as Multitasking Systems. The task can be from single user or from different users also.
What is Distributed Operating System?
These are being widely accepted all-over the world and, that too, with a great pace. Different autonomous interconnected computers communicate with each other using a shared communication network.