Computer Science – Computer architecture | e-Consult

The Von Neumann architecture is characterized by a single address space for both instructions and data. The key components and their purposes are:

• Control Unit (CU): The CU is the "brain" of the computer. Its primary role is to fetch instructions from memory, decode them to determine the operation to be performed, and control the execution of those instructions. It generates control signals that coordinate the activities of other components.
• Arithmetic Logic Unit (ALU): The ALU performs arithmetic (addition, subtraction, etc.) and logical (AND, OR, NOT, etc.) operations on data. It receives data from memory or registers, performs the requested operation, and stores the result back in memory or registers.
• Memory: Memory stores both instructions (the program) and data. It provides a location for the computer to retrieve instructions and data as needed. Memory is typically organized as a sequence of memory locations, each with a unique address.

Interaction during the fetch-decode-execute cycle:

1. Fetch: The CU fetches an instruction from memory. The address of the next instruction is stored in a special register called the Program Counter (PC).
2. Decode: The CU decodes the fetched instruction to determine the operation to be performed.
3. Execute: The CU sends control signals to the appropriate components (e.g., the ALU) to execute the instruction. This may involve fetching data from memory, performing calculations, and storing the result back in memory. The PC is then incremented to point to the next instruction.