Von Neumann Architecture

• Program can be saved like data in the memory unit and can be accessed when needed. This approach is called ‘Stored Program Concept’ and was first adopted by John von Neumann.

• In this architecture, data and instructions are stored in a single set of main memory.
• Instruction fetch and data operation cannot occur at the same time because they share a common bus.
• The program control unit (PCU) reads program instruction, decodes instruction for ALU and determines the sequence of instruction to be executed.
• The ALU performs arithmetic and logical operations.
• It is a basic architecture of today’s computer.
• The another architecture like this is Harvard architecture in which instruction and data have separate memory space; and data & instruction can be accessed at the same time. This is newer approach to von Neumann architecture.