Introduction to

 
Key Terms
Bus: a distinct set of conductors carrying data 
and control signals within a computer system, to 
which pieces of equipment may be connected 
in parallel.
Control Signal: A pulse or frequency of 
electricity or light that represents a control 
command as it travels over a network. 

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Computer System
37
Learning Activity: The Von Neumann Architecture
Introduction
Over the years computer architecture has undergone incredible changes. One thing that 
has been preserved in the influx of changes over the year is the Von Neumann concept of 
computer design. The v
on Neumann architecture
, also known as the von
 Neumann 
model 
and 
Princeton architecture
, is the first model to represent the stored-program 
concept that has fundamentally changed computing[1,2,3]. In the 1940s, a mathematician 
called John Von Neumann described the basic arrangement (or architecture) of a computer 
system. Most computers in use are designed based on the concept described by him although 
there are other types of architecture. 
The following are characteristics of a Von Neumann-based computer:
√ It uses a single processor.
√ It uses one memory for both instructions and data.
√ It cannot distinguish between data and instructions in a memory location
√ It distinguishes between data and instructions only because of the location of a 
particular bit pattern in RAM.
√ Executes programs by doing one instruction after the next in a serial manner 
using a fetch-decode-execute cycle.
Components of the Von Neumann Architecture
Figure 1- The Von Neumann Architecture (Source: Computer 
Architecture and Organization by M. Murdocca & V. Heuring
Fig 1-14 page 10)
The above figure, Figure 1, depicts the essential features of the 
Von Neumann or stored-program architecture

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