ALU: Arithmetic and Logic Unit. This does the caluculations and logic, it’s part of the processor.It has direct input and output access to the processor controller, main memory (random access memory or RAM). The input consists of an instruction word (machine code instruction word) that contains an operation code. The operation code tells the ALU what operation to perform and the operands are used in the operation.
CPU: Central Processing Unit. Thisperforms the actual processing of data. The data it processes is obtained, via the system bus, from the main memory. Results from the CPU are then sent back to main memory via the system bus.
Rgister: The register is the storage. It temporary holds the date thats being processed and it’s very fast.