What is a Multiprocessing Operating System?

An operating system is a crucial part of any computer system. Without an operating system, it can become difficult for a normal user to interact with the system. 

There are multiple types of operating systems available and one of the most popular among them is a multiprocessing operating system.

This type of operating system helps to perform parallel operations in a system as it allows different processors to run different processes at the same time. This results in increased throughput of the system. 

Here, we will be discussing multiprocessing operating systems in detail to give you an idea of how these systems work and why you need one.

What Is A Multiprocessing Operating System?

A multiprocessing operating system is used to enhance the performance of your system by incorporating multiple CPUs in a single system. Different CPUs are connected to a single system so that one job can be divided among them and can be executed faster.

After completion of the job, it will compile the outputs of all CPUs and then provide you with the desired output. Not only this, but a multiprocessing operating system also allows you to run different processes at the same time. 

The most common example of this type of operating system is Unix.

For employing such an operations system, your system must have the following things:

  • The motherboard of your system must be able to handle all the processors at the same time present in the multiprocessing operating system.
  • The processors you choose must be compatible to be used in a multiprocessing system.

Need For Multiprocessing Operating System

What is the need of incorporating a multiprocessing operating system? How is it better than other types of operating systems?

If you are wondering the same, we have come up with some crucial reasons why you need to get a multiprocessing operating system.

  • Increased Throughput: With the increased number of processors, even complex jobs can be done in a small amount of time.
  • Increased Reliability: Now that multiple processors are available, the required task will be divided among different processors. Therefore, if any one of the processors fails, the task can be assigned to another processor which increases the reliability of the whole system.
  • Economical Scalability: The infrastructure used in a multiprocessing operating system is a lot cheaper because different processors will share the same set of resources. Whereas in single-processor systems, each processor will use a separate infrastructure. 

However, besides all these reasons to use a multiprocessing OS, there is no doubt that such systems are complex to manage and handle.

Types of Multiprocessing OS

Multiprocessing operating systems are divided into two major categories. They are

  • Symmetrical multiprocessing OS
  • Asymmetrical multiprocessing OS

Here, we will be discussing the two in detail.

Symmetrical Multiprocessing OS

In a symmetrical operating system, every processor present in the OS will run on the same version of the operating system. Every processor is responsible for making its own decision and collaborating with other processes to help the system run smoothly.

In this type of system, CPU scheduling is also done in a very systematic way. Whenever a new job is given by the user, it will be assigned to the processor which has the least burden. Simply said, the system ensures that all the processors present in the system are equally burdened or taxed.

Now that in this system, processors are using shared memory including the I/O bus, this type of system is also called a “Shared everything” type of system. However, one thing you need to know here is that normally these systems have a maximum of 16 processors. 

Characteristics of Symmetrical OS

  • Every processor runs independently and can run any job or process.
  • This allows any CPU to perform the input and output jobs.

Advantages of Symmetrical Multiprocessing Operating System

  • These systems are fault tolerant. Therefore, if any of the processors fails, there will be no effect on the whole system.
  • All processors use same versions of operating system which makes it easier to distribute processes equally. 

Disadvantages Of Symmetrical OS

  • It can become quite difficult to equally manage the workload among all the processors.
  • To handle so many processors, synchronization algorithms will be needed.

Asymmetric Multiprocessing Operating System

In an asymmetric system, a master-slave relationship is followed. Here, one processor works as a master processor while other processors will be treated as slave processors. 

In such systems, every processor will have a specific task to perform and the operations being performed by other processors are monitored by the master processor.

To understand better, consider that you have a maths coprocessor that is responsible for handling all the mathematical operations whereas an MMX processor is used to handle multimedia operations of the system. 

Other than this, consider that there is a graphics processor that is responsible for handling the graphics-related tasks.

In such a way, each processor is designed to perform a specific task. Now, whenever the user will assign a job to the system, the operating system will choose which task is perfect for which processor and the task will be assigned to that processor. The operations system here becomes the control and master of the system.

Whereas, all the other processors present in the system wait for getting instructions from the master to perform a task. 

Advantages of Asymmetric OS

  • Since there are multiple processors available to perform a single task, there are times when the input and output execution is faster in these systems.
  • Different processors can be used to perform different tasks. 

Disadvantages of Asymmetric Multiprocessing OS

  • There is an unequal burden on all the processors available in the system. In such a case, one CPU may have a lot of processes in the queue, another one may be idle. Other than this, there are also high chances of facing thrashing in an Operating System of this type as the same processor may get stuck at page faults for a long time.


A Multiprocessing operating system allows you to run multiple processors at the same time which in turn reduces the throughput of the system. There are two types of multiprocessing OS available that you can use and each of them has its pros and cons. 

However, before implementing such systems, you need to know that such systems are quite complex and can be difficult to install and manage at times. 

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