Central Processing Unit and Cooling Systems May 2016 | Page 9

On a technical level, there are three main components of a CPU:
1. Arithmetic Logic Unit (ALU)
The ALU is the part of a CPU that performs all arithmetic computations including addition, subtraction, multiplication, and division. The
Arithmetic Logic Unit also performs all logical operations. The ALU is a literally the fundamental building block of the CPU, and even the
simplest processors contain an ALU.
Today's modern CPUs and graphics processing units (GPUs) in graphic cards have very complex ALUs, and some contain a number of
ALUs.

2. Control Unit
The CPUs control unit is responsible for executing or storing the results coming out of the ALU. Within the CPU, the control unit
performs the functions of fetch, decode, execute, and store.
The control unit communicates with both the arithmetic logic unit (ALU) and memory, and literally directs the entire computer system
to carry out, or execute, stored program instructions.
In a nutshell here is how a control unit works. Basically a control unit fetches or retrieves an instruction from memory and then analyses
the instruction it fetched before deciding how it should be processed. Depending on the action required, the control unit will then send
segments of the original instruction to the appropriate section of the processor.