Difference Between Von Neumann Architecture and Harvard Architecture (With Table)

Von Neumann Architecture vs Harvard Architecture

The difference between Von Neumann architecture and Harvard architecture is that in Von Neumann there is a single memory for both, program and data. There is no separate memory for them, whereas in Harvard architecture there are both program memory and data memory and the CPU is connected with both of them separately.

The word architecture reminds us of building a house. In the same concept, computer architecture means building a computer. The term architecture in computers may seem complex, but it is quite easy.

It is basically a set of methods and rules that states how the computer’s hardware and software are linked together and how they make the computer function. Not only does it describe how a computer functions, but also determines the technologies that the computer is capable of.

Von Neumann architecture and Harvard architecture are the different types of computer architecture.

 

Comparison Table Between Von Neumann Architecture and Harvard Architecture (in Tabular Form)

Parameter of ComparisonVon Neumann ArchitectureHarvard Architecture
ArrangementIn this architecture, there is one memory for both, data and program memory. There are no separate memories.In this architecture, there are both program memory and data memory and the CPU is connected to them separately.
Requirement of spaceLess space is required in Von Neumann architecture.More space is required in Harvard architecture.
ControlIt is simple to control because either instructions or data are to be brought at a single time.It is complex to control because instructions and data are to be brought at once.
Execution speedThe execution speed is slow because the instructions and data cannot be fetched at one time. The execution speed is fast since the instructions and data can be fetched at the same time.
Requirement of hardwareIn this architecture, less hardware is required because there is a common memory.In this architecture, more hardware is required because there are different memory for data and program.

 

What is Von Neumann’s Architecture?

Von Neumann architecture is a computer architecture design that was proposed by Von Neumann in 1945. It comprised of a Logical Memory Unit, Control Unit, Registers, Arithmetic, and Inputs/Outputs.
It was formed on a concept, where program data and instruction data are kept in the same memory. This architecture is in use today also in most computers.

A Von Neumann architecture computer is one in which a single processor is used. In this, one memory is used for both data and instructions.
Von Neumann’s design is simpler and easier than Harvard’s architecture.

The components of the Von Neumann Model are:

  1. Central Processing Unit- It is the Central Processing Unit that carries out the processing operations of the bulk of data and it is often referred to as CPU.
  2. Buses- The modes through which the information is shared among the registers, are the Buses.
    Von Neumann Architecture is composed of 3 major bus systems for transferring data.
  3. Memory Unit- A group of storage cells along with related circuits required for transferring information back and forth of the storage is called the Memory Unit.
Von Neumann Architecture 1
 

What is Harvard Architecture?

A normal computer that obeys von Neumann architecture, both instructions, and data is stored in the same memory. This means the same buses are used to get instructions and data.

This becomes difficult as the CPU cannot perform both the tasks simultaneously i.e. read the instruction and read/write data.

Harvard Architecture is a type of computer architecture that contains unique storage and unique buses (signal path) for both instruction and data. This was primarily developed to get better than the Von Neumann Architecture.

The basic advantage of having different buses for instruction and data is that the CPU can understand instructions and read/write data simultaneously.

Structure of Harvard Architecture:

  1. Buses- These are used as signal pathways. There are different buses for both instruction and data.
  2. Operational registers- There are many types of registers required in it which are used for keeping address of different types of instructions.
  3. Program Counter- This contains the location of the following instruction to be carried out. It then passes this address to the memory address register.
  4. Arithmetic and logic unit- This unit is that part of the CPU that solves all the calculations needed.
  5. Control unit- This controls all processor control signals.
  6. Input/output system- Input devices read data into the main memory using the CPU input instruction. The Output devices give the information from a computer as output.

Harvard Architecture

Main Differences Between Von Neumann Architecture and Harvard Architecture

  • In Von-Neumann architecture, there is a single memory for both, program and data and there is a single CPU connection for both. In Harvard architecture, there are different program memory and data memory and the CPU is connected to them separately.
  • There is no wastage of space in Von Neumann architecture because the data memory space can be used by the instructions memory and vice-versa, whereas in Harvard architecture, space is wasted because the remaining space in the data memory cannot be used by the instructions memory and vice-versa.
  • It is simple to control Von Neumann architecture because either instructions or data are to be brought at a single time, whereas in Harvard architecture, it is complex to control it because instructions and data are to be brought at once.
  • Less space is required in Von Neumann architecture, whereas more space is required in Harvard architecture.
  • In Von Neumann architecture, less hardware is required because there is a common memory for data and program, whereas, in Harvard architecture, more hardware is required because there are different memory addresses for data and program.

 

Conclusion

In conclusion, it can be said that there is not much difference between Von Neumann architecture and Harvard architecture, except that Von Neumann uses a single bus to carry both data and instruction transfers.

On the contrary, the Harvard architecture uses different memory addresses for instructions and data, because of which execution speed is fast since the instructions and data can be fetched at the same time.

 

Word Cloud for Difference Between Von Neumann Architecture and Harvard Architecture

The following is a collection of the most used terms in this article on Von Neumann Architecture and Harvard Architecture. This should help in recalling related terms as used in this article at a later stage for you.

Difference Between Von Neumann Architecture and Harvard Architecture