Purpose and components of the CPU

The Central Processing Unit (CPU) works like the brain of the computer and is responsible for carrying out instructions that make software and hardware work.
The CPU’s main responsibilities are to:
- Carry out instructions from programs
- Process data inputs from programs and storage
- Control the rest of the computer system using control signals

Component	Function
Arithmetic Logic Unit (ALU)	The ALU is responsible for calculations and logic. It performs calculation operations like addition, subtraction, multiplication, and division. It also makes logical comparisons, like checking if one number is greater than the other or if the two values are equal. When the CPU needs to decide between things or carry out a calculation, it uses the ALU.
Control Unit (CU)	The CU tells the rest of the computer how to respond to the instructions it receives. It manages the flow of data around the CPU and between the CPU and other components like memory or input/output devices. It sends control signals to other components to coordinate what happens and when, and helps to decode instructions so the CPU knows what action to take.
Cache	The cache is a small amount of very fast memory located close to or inside the CPU. It stores frequently used data and instructions, so the CPU doesn’t have to keep going back to RAM, which is much slower. This helps the CPU work faster and more efficiently. There are usually different levels of cache (L1, L2, L3) – the lower the number, the faster and smaller it is.
Registers	Registers are tiny memory locations within the CPU itself that store small amounts of data temporarily while instructions are being executed. Registers are the fastest type of memory. Different registers have different roles – for example, some store memory addresses, others store data being worked on.

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