Difference between Von Neumann and Harvard Architecture

Von Neumann and Harvard architectures are the two basic models in the field of computer architecture, explaining the organization of memory and processing units in a computer system. For those involved in Computer Science or working in companies providing computing technologies, it is essential to understand the characteristics of these architectures.

There are two models of multiprocessing architectures: Von Neumann and Harvard. While the former occupies a dominant position, this article will discuss its principal differences from the latter, along with their respective advantages and disadvantages, to help you understand which architecture is more suitable for a given application.

Von Neumann Architecture

Von Neumann Architecture is a digital computer architecture whose design is based on the concept of stored program computers where program data and instruction data are stored in the same memory. This architecture was designed by the famous mathematician and physicist John Von Neumann in 1945. 

Advantages of Von Neumann Architecture

• Simplicity: The fact that all data and instructions are stored in a single memory space helps the process of designing a computer system as there is no need to create complicated systems of routing since pathways may coincide.
• Cost-Effective: A smaller number of components is needed as compared to the other architectural designs hence more economical.
• Flexibility: A program can Always be changed or altered without experiencing a change in some underlying physical aspects such as the circuitry.

Disadvantages of Von Neumann Architecture

• Bottleneck Issues: The shared bus can be a problem because the data and control instructions cannot be obtained simultaneously and therefore it becomes slow.
• Memory Corruption: Since the data and instructions reside in the same memory, then there is a temptation of one erasing the other thereby producing system faults.

Harvard Architecture

Harvard Architecture is the digital computer architecture whose design is based on the concept where there are separate storage and separate buses (signal path) for instruction and data. It was basically developed to overcome the bottleneck of Von Neumann Architecture. 

Features

• Separate memory spaces
• Fixed instruction length
• Parallel instruction and data access
• More efficient memory usage
• Suitable for embedded systems
• Limited flexibility

Advantages of Harvard Architecture

• Faster Processing: The availability of two buses for data and instructions avoids a problem of contention where only one bus is used and this enhances the velocity of the system.
• Improved Security: In this way the chance of memory corruption is at least cut in half since data is not stored in the same locations as instructions.
• Efficient Use of Resources: It enables the use of different memory for data and for instructions of different sizes as this help in optimal utilization of the buses and other resources.

Disadvantages of Harvard Architecture

• Complexity: The design and the implementation of this type are more intricate, thus necessitating other hardware facilities.
• Higher Cost: Since the concept of Harvard architecture calls for two sets of memory and two separate buses, their implementation costs are comparatively high than Von Neumann architecture.
• Less Flexibility Competitors : Changing or even improving the system can also be a little tricky because of the different memory regions.

Difference between Von Neumann and Harvard Architecture