Multiprocessing Operating System

Multiprocessing operating system is desinged to have more than one processor which work simultaneously in a single computer system to perform the required operations. It allows the multiple processors, and they are connected with physical memory, computer buses, clocks, and peripheral devices. Or we can say that the main objective of using a multiprocessor operating system is to increase the execution speed of the system and consume high computing power.

The processor in multiprocessor system can communicate and cooperate at various levels of solving a given problem. The communications between the processors take place by sending messages from one processor to another, or by sharing a common memory.

Features of Multiprocessor Operating System

Following are some important features of the multiprocessor operating system which we must know about before using it−

• Parallel Computing This involves the simultaneous application of multiple processors. These processors are developed using a single architecture to execute a common task. In general, processors are identical and they work together in such a way that the users are under the impression that they are the only users of the system. In reality, however, many users are accessing the system at a given time.

• Distributed Computing This involves the usage of a network of processors. Each processor in this network can be considered as a computer in its own right and have the capability to solve a problem. These processors are heterogeneous, and generally, one task is allocated to a single processor.

• Supercomputing This involves the usage of the fastest machines to resolve big and computationally complex problems. In the past, supercomputing machines were vector computers but at present, vector or parallel computing is accepted by most people.

• Pipelining This is a method wherein a specific task is divided into several subtasks that must be performed in a sequence. The functional units help in performing each subtask. The units are attached serially and all the units work simultaneously.

• Vector Computing It involves the usage of vector processors, wherein operations such as multiplication are divided into many steps and are then applied to a stream of operands (vectors).

• Systolic This is similar to pipelining, but units are not arranged in a linear order. The steps in systolic are normally small and more in number and performed in a lockstep manner. This is more frequently applied in special-purpose hardware such as image or signal processors.

Type of Multiprocessing Operating System

The different fields of multiprocessor operating systems used are as follows−

• Asymmetric Multiprocessor: Every processor is given seeded tasks in this operating system, and the master processor has the power for running the entire system. In the course, it uses the master−slave relationship.

• Symmetric Multiprocessor: In this system, every processor owns a similar copy of the OS, and they can make communication in between one another. All processors are connected with peering relationship nature, meaning it wont be using master & slave relation.

• Shared memory Multiprocessor: As the name indicates, each central processing unit contains distributable common memory.

• Uniform Memory Access Multiprocessor (UMA): In this system, it allows accessing all memory at a consistent speed rate for all processors.

• Distributed memory Multiprocessor: A computer system consisting of a range of processors, each with its own local memory, connected through a network, which means all the kinds of processors consist of their own private memory.

• NUMA Multiprocessor: The abbreviation of NUMA is Non-Uniform Memory Access Multiprocessor. It entails some areas of the memory for approaching at a swift rate and the remaining parts of memory are used for other tasks.

Benifits of Multiprocessing Operating System

Following are the benefits of multiprocessor operating system−

• If there are multiple processors working at the same time, more processes can be executed parallel at the same time. Therefore the throughput of the system will increase.

• Multiprocessor systems are more reliable. Due to the fact that there are more than one processor, in case of failure of any one processor will not make the system come to a halt. Although the system will become slow if it happens but still it will work.

• Electricity consumption of a multiprocessor system is less than the single processor system. This is because, in single processor systems, many processes have to be executed by only one processor so there is a lot of load on it. But in case of multiple processor systems, there are many processors to execute the processes so the load on each processor will be comparatively less so electricity consumed will also be less.

• Multiple processors can handle more tasks simultaneously without degrading the performance.

Limitations of Multiprocessing Operating System

Following are the limitation of multiprocessor operating system−

• It requires a sophisticated design to manage multiple processors.

• Multiprocessing is some what expensive as comapred to single processing system.

• Not all the software supported multiprocessing system. So multiprocessing software faces software limitation problem.

• Multiprocessing systems require advance hardware so that they can easily manage multiple CPUs, or other processors, it rises the cost of multiprocessing systems.