The illustration above shows the essential features of the Von Nuemann or stored-program architecture.
Memory
The computer will have memory that can hold both data and also the program processing that data. In modern computers this memory is RAM.
Control Unit
The control unit will manage the process of moving data and program into and out of memory and also deal with carrying out (executing) program instructions- one at a time. This includes the idea of a ‘register’ to hold intermediate values. In the illustration above the ‘accumulator’ is the one such register.
The ‘one-at-a-time’ phrase means that the von nuemann architecture is a sequential processing machine.
Input-Output
This architecture allows for an idea that a person needs to interact with a machine. Whatever the values that are passed to and forth are stored once again in some internal registers.
Arithmetic Logic Unit
This is the part of architecture that is solely involved with carrying out calculations upon data. All the usual Add, Multiply, Divide and Subtract calculations are available but also data comparisons such as ‘Greater than’, ‘Less than’, ‘Equal to’ will be available.
Bus
Notice the arrows between components? This implies that information should flow between various parts of the computer. In a modern computer built to the Von Nuemann architecture, information passes back and forth along a ‘bus’. There are buses to identify locations in memory – an ‘address bus’
And there are buses to allow the flow of data and program instructions- a ‘data bus’.
Conclusion
The Von Nuemann architecture has been incredibly successful, with most modern computers following the idea. You will find the CPU chip of a personal computer holding a control unit and arithmetic logic unit (along with some local data) and the main memory is is in the form of RAM sticks located on the motherboard.
But there are some basic problems with it and because of these problems, other architectures have been developed.
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