Difference between Multiprocessing and Multiprogramming

Multiprocessing and Multiprogramming both strategies are designed to increase the efficiency of the system by managing multiple tasks but with different principles of their own. But they share the common goal which is improving resource utilization and system throughput. So, understanding which one to use in the modern computer system is necessary.

What is Multiprocessing?

Multiprocessing is a system that has two or more processors. In this, CPUs are added to increase the computing speed of the system. Because of Multiprocessing, many processes are executed simultaneously. This approach enhances performance by leveraging parallelism to handle more tasks at once. Multiprocessing is further classified into two categories: Symmetric Multiprocessing and Asymmetric Multiprocessing.

• Asymmetric multiprocessing: a specific task is allocated to a particular processor, not every processor can perform all the tasks. Typically, there are slave processors present that execute tasks based on the Master processor (who controls the system) assigning the tasks to the slave processors.
• Symmetric multiprocessing: all the processors have equal access to all resources and are capable of executing any task allocated to them. They share a common memory space which helps to communicate processors and data sharing between them.

Advantages of Multiprocessing

• Efficient Resource Utilization: Multiple processors improve efficiency and reduce the bottlenecks by better utilization of resources and can share the workload.
• Reliability is improved: If one processor fails, then others can continue that work which makes the system more robust.
• Increased Throughput: This leads to higher overall performance of the system as multiple CPUs are used, so a system can process more tasks simultaneously.

Disadvantages of Multiprocessing

• Complexity: As here multiple processors are used which makes the management or processors complex, so a sophisticated operating system and software are required to coordinate tasks.
• Cost: These types of systems are generally more expensive than single-processor systems.
• Resource Contention: There are multiple processors used which may compete for the shared resources and which causes conflicts between processors and reduced performance.

Now, let's discuss multiprogramming in detail

What is Multi-programming?

Multi-programming involves more than one process running at a time on a single processor system, it increases CPU utilization by organizing jobs (code and data) so that the CPU always has one to execute and maximize resource utilization as well. The motive is to keep multiple jobs in the main memory. If one job gets occupied with Input/output, the CPU can be assigned to other jobs. This ensures that the CPU is always in use and cannot be idle.

Advantages of Multiprogramming

• Increased CPU Utilization: The CPU idle or minimizes the idle time in multiprogramming as the CPU is busy with multiple programs or tasks to execute.
• Enhanced System Throughput: In a given time frame the system can handle more tasks if multiple programs are in memory.
• Efficient Resource Use: This helps in utilizing system resources effectively by overlapping the I/O operations with CPU processing.

Disadvantages of Multiprogramming

• Overhead and Reduced Performance: When the programs are switching then saving and restoring the state of each program is required, which consumes the time of CPU and can impact overall performance. Also, the time required to switch between programs leads to increased latency and affects the responsiveness of the system.
• Management is complex: Managing multiple programs requires complex scheduling algorithms to ensure fair and efficient allocation of CPU time. It is an overhead for the operating system which impacts overall system performance.
• Resource Contention: This creates memory conflicts, as multiple programs run simultaneously and compete for limited memory resources. This can cause memory fragmentation and reduced performance if not managed effectively.
• Overcommitted Resources: If the system is overloaded with too many programs at the same time can lead to resource exhaustion, where the system has a lot of workload and is not able to handle it, resulting in degraded performance.

Difference between Multiprocessing and Multiprogramming

Conclusion

Both Multiprogramming and Multiprocessing aim to improve the performance of the system, the both have different principles to work with. Multiprocessing focuses on parallel execution using multiple CPUs in a single system, while multiprogramming enhances CPU utilization and reduces CPU idle time by managing multiple programs on a single processor. Understanding these differences helps in choosing the right and necessary approach based on the specific needs and constraints of a computing environment.