An operating system is a program that acts as a link between the user and the computer system. The presence of an OS is very important as without it other programs can’t run. Thus, it manages the resources on a system and they cannot function when the OS is absent. It has existed since the first generation of computers and has been evolving with time. Learn about various types of the operating system.
Types of Operating System
One of the important parts of this evolution is the types of operating system. There are five major types of OS, namely:
1. Batch Operating System
2. Time-Sharing Operating System
3. Distributed Operating System
4. Network Operating System
5. Real-Time Operating System
1. Batch Operating System
In this type of operating system, users didn’t interact with the OS directly. Jobs were prepared on an offline device such as a punch card and were then submitted to the computer operator. To speed up processing, the users left their programs with the operator. This operator took the jobs with similar requirements and grouped them into batches and then ran them as a group.
- The time required for a job to complete is predictable as the jobs are in a queue.
- Multiple jobs can share the systems.
- Reduced idle time.
- It is easy to process and manage a large workload.
Disadvantages of Batch Operating System:
- Zero interaction between the user and the system.
- Debugging is harder as the operator needs to be thorough with the batch systems which is difficult.
- It is costly.
- If one job fails, the OS puts the other jobs on a stand-by for an unknown time period.
- CPU is often left idle during processing as the speed of the mechanical I/O devices is slower as compared to the CPU.
2. Time-Sharing Operating System (Multitasking Operating System)
In this type of Operating System, the user directly gives instructions to an OS, and the OS executes multiple tasks at a time. The computer memory stores these programs and they share a single processor. The tasks switch rapidly from one to another giving immediate response to the user(s). It is an interactive system at a reasonable price.
It uses the concept of CPU scheduling and multiprogramming so that the time of the CPU is divided equally among the tasks. This allows all the tasks to work smoothly. As the interactive I/O is slower as compared to the CPU, this OS also increases CPU utilization as there is always a spare job to execute.
This OS focuses on decreasing the response time of a task. The time taken to execute a single task is called quantum. Once this time interval is over the OS switches to the next task.
Advantages of Multitasking Operating System:
- Each program receives equal time to use the CPU.
- Software duplication is difficult.
- CPU is no longer left idle.
Disadvantages of Multitasking Operating System:
- Due to multiple sharing, it is unreliable.
- Data integrity and security are threatened.
- Data communication is difficult.
3. Distributed Operating System
In this type of operating system, multiple CPUs are used to serve multiple processes and users. All the computers have their own memory unit and CPU, and are interconnected and communicate with each other over a shared communication network. The processors differ in size and function and remote access is enabled within the devices connected to a network. The job of data processing is distributed among various processors which makes the jobs more efficient.
Advantages of Distributed Operating System:
- If one system collapses the others are not affected by it as they are independent of each other.
- Increased data exchange speed and reduced load on the host computer.
- Computation is highly fast and durable due to shared resources.
- It is easily scalable due to the attachment of multiple systems.
- Reduced delay in the data processing.
Disadvantages of Distributed Operating System:
- A single system failure might not affect the entire communication but the failure of the main network can crash it.
- Languages used to establish distributed operating systems are not well established.
- It is not readily available as it is very expensive and complex.
4. Network Operating System
This OS runs on a server allowing it to manage data, users, groups, security, applications, and other networking functions. It allows shared access of files, printers, security, applications, and other networking functions over a small private network or a LAN. Users are well aware of its underlying configuration, making it a tightly coupled system.
Advantages of Network Operating System:
- It has stable and centralized servers that can handle security concerns well.
- Integration of new technologies and hardware up-gradation is easier.
- Remote server access is possible.
Disadvantages of Network Operating System:
- High cost of servers.
- Most operations could only be performed through a central location.
- It requires regular maintenance and updating.
5. Real-Time Operating System
In this type of operating system, the time required to process and respond to inputs is very small. This time taken by the system to respond to an input and display the response is known as response time. This is often used when there are rigid time requirements or in control devices. This has defined time constraints for the system to run smoothly.
There are two types of Real-Time Operating systems:
a. Hard Real-Time Systems: Have highly strict time constraints to make sure that critical tasks are completed on time. There is limited secondary storage and the data is often stored in ROM with no virtual memory.
b. Soft Real-Time Systems: They have a less strict time constraint and critical tasks are given priority above others until they are completed and have limited utility.
Advantages of Real-Time Operating System:
- More output from resources is received due to the maximum utilization of devices and systems.
- Less time is required for task shifting.
- It focuses more on running applications.
- Due to the small size of programs, they can be used in embedded systems.
- It is error-free.
- The best management of memory allocation.
Disadvantages of Real-Time Operating System:
- Very few tasks run at the same time in order to avoid errors.
- The system resources are usually very expensive.
- Complex algorithms that are difficult to write on.
- It needs specific interrupts signals and device drivers to respond earliest to interrupts.
- Thread priority can’t be set as these systems don’t usually switch tasks.
Above were the major types of Operating System. These are usually used in devices like desktops, PCs, etc… Apart from these five, there are some other types of Operating System too that are more familiar to people. These include:
1. Mobile Operating System
2. Embedded Operating System
3. Multiprogramming Operating System
4. Multiprocessor Operating System
5. Desktop Operating System
6. Clustered Operating System
7. Handheld Operating System
1. Mobile operating system
This OS is designed especially for powering smartphones, tablets, and wearables devices. Some common OS are Android, iOS, BlackBerry, Web, and watchOS.
2. Embedded Operating System
This OS performs a specific task for a particular device but this device can be anything but not a computer. Some common examples of this are elevators, GPS systems, fitness trackers, etc… It allows the device hardware to access the software running on the OS. Though only one task can be performed on this OS, it is fast, cheap and consumes less memory and resources.
3. Multiprogramming Operating System
In this, the multiple tasks are stored in the system memory that are acquired from the job pool and the OS picks one task and starts executing it. Then, when the current job requires an I/O, the OS fetches another job from the memory. In the case of multiple jobs in ready state, which job to choose is decided through the process of CPU Scheduling. It makes sure that the CPU is never left idle and focuses on maximizing the CPU usage.
Time-Sharing OS is an extension to the multiprogramming operating system. The only difference between these two is that this OS focuses on increasing processor use whereas the other focuses on decreasing the response time.
4. Multiprocessor Operating System
As the name suggests, this OS consists of multiple processors that share a common physical memory and that operate under a single OS. The system divides a task into subtasks which are executed parallely in different processors. It provides high computing power and increased system throughput and speed. Working of these processors is transparent to the users.
5. Desktop Operating System
This OS focuses on increasing user convenience and system responsiveness. Microsoft Windows and the Apple Macintosh are two examples of this OS. This helped the microcomputers adapt some of the technologies developed for larger operating systems and also reduced the hardware costs.
6. Clustered Operating System
In this OS, a cluster of CPUs is formed to accomplish computational work. The systems share storage and are closely linked through a LAN network. A cluster software runs on nodes where each node monitors one or more other nodes. If any failure occurs in the monitored machine, the monitoring machine takes ownership of its storage, and restarts the application(s) running on that node.
There are three types of clustering. Asymmetric clustering where one machine(host) monitors the active server while the other is running the applications. If the running machine fails, the host machine takes over the active server. Symmetric clustering where two or more hosts run applications while monitoring each other. It uses all the available hardware. Parallel clustering where multiple hosts access the same data on the shared storage.
7. Handheld Operating System
Handheld systems are usually cellular phones with connection to a network like the Internet, bluetooth with limited size, small physical memory, slow processors, and small display screens. The memory size usually being between 512 KB and 8 MB, the OS needs to manage the memory efficiently and return the allocated memory back to the memory manager when not in use. These are usually used for sending emails and web browsing.
Summary
An OS is an interface that helps the user communicate with a system. We have seen various types of Operating systems and their features.
Hope the article was useful to you.
