Some of the most widely used types of Operating system.
- Simple Batch System
- Multiprogramming Batch System
- Multiprocessor System
- Distributed Operating System
- Clustered System
- Realtime Operating System
- Handheld System
1. Simple Batch System:
- In this type of system, there is no direct interaction between user and the computer.
- The user has to submit a job written on cards or tape to a computer operator.
- Then computer operator places a batch of several jobs on an input device.
- Jobs are batched together by type of languages and requirement.
- Then a special program, the monitor, manages the execution of each program in the batch.
- The monitor is always in the main memory and available for execution.
2. Multiprogramming Batch System:
- In this the OS picks up and begins to execute one of the jobs from memory.
- Once this job needs an I/O operation OS switches to another job (CPU and OS always busy).
- Jobs in the memory are always less than the number of jobs on disk.
- If several jobs are ready to run at the same time, then the system chooses which one to run using CPU Scheduling.
- In Non-multiprogrammed system, there are moments when CPU sits idle and does not do any work.
- In Multiprogramming system, CPU will never be idle and keeps on processing.
3. Multiprocessor System:
- A Multiprocessor system consists of several processors that share a common physical memory.
- Multiprocessor system provides higher computing power and speed.
- In multiprocessor system all processors operate under single operating system.
4. Distributed Operating System:
- In this type of OS multiple systems involved, user at one site can utilize the resources of systems at other sites.
Following are the two types of distributed operating systems used:
- Client-Server Systems
- Peer-to-Peer Systems
5. Clustered System:
- Clustered systems gather together multiple CPUs to accomplish computational work.
- Clustered computers share storage and are closely linked via LAN networking.
- Clustering is usually performed to provide high availability.
- A layer of cluster software runs on the cluster nodes.
- Each node can monitor one or more of the others.
6. Realtime Operating System:
- It is defined as an OS known to give maximum time for each of the critical operations that it performs, like OS calls and interrupt handling.
- The Real-Time Operating system which guarantees the maximum time for critical operations and complete them on time are referred to as Hard Real-Time Operating Systems.
- While the real-time operating systems that can only guarantee a maximum of the time, i.e. the critical task will get priority over other tasks, but no assurity of completeing it in a defined time. These systems are referred to as Soft Real-Time Operating Systems.
7. Handheld System:
- Handheld systems include Personal Digital Assistants(PDAs), such as Palm-Pilots or Cellular Telephones with connectivity to a network such as the Internet. They are usually of limited size due to which most handheld devices have a small amount of memory, include slow processors, and feature small display screens.