The central processing unit

index > 2.1.2 computer hardware


Hardware is the physical components of a computer system. It is anything that can be seen or touched.

Hardware components include input, output, storage and processing devices.

The central processing unit (cpu)

CPU stands for Central Processing unit. It is often described as the brain of the computer as it is responsible for processing data. The purpose of the CPU is to carry out a computer’s processing (to fetch, decode and execute instructions).

The CPU is made up of 2 major parts:

The ALU (Arithmetic and Logic Unit) is responsible for logical calculations and arithmetic equations.

The control unit controls the flow of data. It takes an instruction, processes it, and produces an output which is sent to be used/run by other hardware in the computer.

The different parts of the CPU work together to carry out the fetch-decode-execute cycle. This is how processors function and control the computer.

The speed of the CPU is effected by:

A computer’s clock speed, or number of fetch-decode-execute cycles per second is measured in Hertz (Hz). Nowadays, most processors clock speeds are measured in Gigahertz (GHz) due to the huge number of cycles.

Cache memory is the lowest level of memory, meaning it is closest to the CPU. The bigger the processor’s cache, the faster it is as more information can be stored there. It is used to store frequently accessed data, for faster access speeds. If the required data is not in the cache memory the CPU will search the system memory and add it to the cache memory and then process it.

Multiple processor cores make a computer better at multitasking, as different cores can carry out different operations simultaneously. However, carrying out individual instructions does not get any quicker with multiple cores.