Von Neumann architecture

2. Von Neumann layout

A diagram of the Von Neumann architecture is shown below.

Note that a 'computer architecture' is not an actual computer - it is an idea of how a computer should be built.

The essential idea of the Von Neumann architecture is that both program and the data being used by that program are stored in a common memory block and they also share the same address and data bus.

What this means is that the operation of the computer can be changed immediately by simply running a different program in memory.

Modern computers have enough memory to support dozens of programs being held in memory but only one of them can execute instructions at any instant. A process scheduler handlies the switching between programs.