Operating Systems can be divided into different manner such as as per their features, tasks etc. Here I have listed out some important types of operating system:
1. Batch Operating System:
- In olden day computers were large machines.
- Common input devices were card readers, tap drives.
- Common output devices were tap drives, line printers and punch cards.
- Operating system was very simple.
- Operating system was normally laid into main memory.
- Programmers would generate programs and submit to the operator.
- After that operator would sort such programs into batch as per the requirements.
- Whenever any computer system would be available, operator run that program batch wise.
- After some days or some hours computer system would generate the result. Such result had the output of the program and error information.
- Programmers had to wait for some time to get the result of their jobs or we can say programs.
- After that programmers would collect the output from the operator.
- Here in this type of operating systems, memory is divided into two parts i.e. jobs (programs) and operating system.
- At a time only one job of a batch can be executed.
2. Multi Programming Operating System:
- Multi programming operating system is that OS which allows users to run more than one program at the same time.
- Multi programming operating system overcomes the main disadvantage of the batch operating system.
- In batch operating system only one job can be executed at a time while in multi programming operating system, more than one jobs can be executed at a same time so that computer resources such as CPU can be used at a maximum level.
3. Time Sharing Operating System:
- Time sharing operating system is a logical extension of Multi programming operating system.
- In this operating system, CPU is multiplexed by time among several jobs or programs laid on the disk.
- Time sharing operating system works in primitive manner.
- Here a specific time period is allocated for the execution of a particular program.
- After completion of that time period, CPU is taken away and allocated to another programs.
- Here the response time to the user is very fast.
- This type of operating system is also known as Multi tasking operating system where users can work on more than one programs at a same time.
- In today's era, most of the operating systems running on the personal computers are of this category.
4. Real Time Operating System:
- In Real time operating system, time is the key parameter.
- Real time operating system strictly process input data in a pre-defined time duration.
- Here output is greatly affected by input.
- In practical world, this type of operating system can be seen in Nuclear power plant, Oil refining industries, Air traffic control system, Air defense systems etc.
- There are mainly two types of Real time operating system i.e. Hard real time operating system and Soft real time operating system.
- In Hard real time operating system, all critical tasks must get completed within pre-defined time period.
- While in Soft real time operating systems, there is also the chances of missing an occasional dead line.
5. Multi User Operating System:
- Multi user operating system is totally different from single user operating system.
- In Multi user operating system, more than one users can use the computer system with the use of Terminal of Computer.
- Terminal is a inter mediate device between user and computer system.
- Terminal can have only two devices i.e. keyboard and monitor.
- Example of such terminal is ATM machine.
- Multiple users can access the single computer system through time-sharing and multi programming systems.
- Examples of multi user operating system are Unix, VMS and mainframe operating systems such as MNS.
- Multi user operating system is more complex than single user operating system.
- This operating system is more costly than single operating system.
- Moreover, when number of users increases, performance also decreases in this system.
- No doubt, many costly resources like printers can be shared in this operating system.
6. Multi Processing Operating System:
- The operating system that supports multiple processors is known as Multi processing operating system.
- Multiprocessing operating system is connected with Multi programming operating system.
- Multiprocessing operating system allows to run more than one program at the same time.
- As per the architecture of computer system, Multiprocessing operating system is classified into two categories i.e. AMP (Asymmetric Multiprocessing) and SMP (Symmetric Multiprocessing)
7. NOS (Network Operating System):
- Network operating system allows you to interconnect different computer systems into a network.
- In this operating system, users can access resources from the remote computer and/or also can transfer data/file from the remote computer into their own system.
- In each computer system, there is separate operating system.
- If user wants to access from the remote machine then he/she has to login to that remote machine.
- Different resources like printers, scanners etc can be shared in this system.
- NOS requires NIC (Network Interface Card) and some drivers to provide networking functionalities.
- Windows 2000 and Novel Netware are single user operating systems that supports networking.
8. DOS (Distributed Operating System):
- Distributed operating system distributes tasks among different processors.
- In this system, users are not aware about the existence of other machines.
- When there is a high load on a processor then this system automatically distributes tasks or computations to another machines with idle processor.
- Distributed operating system is more complex than Network operating system.
9. Multi Threading Operating System:
- Multi threading operating system supports the concept of multiple threads into single environment.
- This system supports to run different thread of a single software at the same time.
- Thread is a part of process that can be executed independently from the another part of process.
- Thread is also said as a flow of control of a process.
- A process which has many threads are known as multi threaded process.
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