Computer Organization

The classic description of a computer's organization is attributed to John von Neumann (1903-1957), though his original description of a machine named the EDVAC was far more complex. The von Neumann model is characterized by:

Five major subsystems:

1. Memory

2. Input
3. Output

4. Arithmetic-logic unit (ALU)

5. Control unit

Note: the ALU and control unit together are usually referred to as the central processing unit (CPU) or simply, the processor.

The stored program concept:

instructions are represented in binary and stored in the memory, from which they are fetched, decoded, and executed by the CPU. The concept of the stored program is also commonly attributed only to John von Neumann, but in fact it was the original design of the members of the ENIAC project.