CPU

The CPU, or Central Processing Unit, of a computer is the component that performs all of the basic data processing operations of the system, including exchanging data with its memory and peripheral devices. It is sometimes described as the brain of a computer, and is the part responsible for processing and executing instructions from applications such as web browsers, games and productivity tools. CPUs are found in all types of computers from smartphones to supercomputers.

Brain Processor CPU by Max Pixel, CC 0

A CPU is a microprocessor, which means it is made up of billions of tiny transistors that can turn on and off very quickly to perform calculations. The more transistors a CPU has, the more powerful it is. Modern CPUs have billions of transistors packed onto a small piece of silicon, allowing them to perform complex tasks at incredible speeds.

The CPU is connected to other components of the computer, such as the memory and storage, via a 'bus system'. The bus system allows data to be transferred between the CPU and other components quickly.

The CPU has several components that work together to execute instructions. These include:

• The control unit, which fetches instructions from memory and decodes them into a form that the CPU can understand. The control unit then sends these instructions to the next component...
• the arithmetic and logic unit (ALU). The ALU performs mathematical calculations, such as addition, subtraction, multiplication, and division, as well as logical operations, such as AND, OR, and NOT. These operations are performed on data stored in registers, which are small, high-speed memory locations within the CPU. The CPU also has...
• cache memory, which is a small amount of high-speed memory located on the CPU chip itself. Cache memory is used to store frequently accessed data and instructions, allowing the CPU to access them quickly and reduce the time it takes to fetch data from main memory.

Modern CPUs also have multiple cores, which means they have several independent processing units within a single CPU. Each core can execute instructions independently, allowing the CPU to perform multiple tasks simultaneously. This is known as 'parallel processing' and can significantly improve the performance of programs that are designed to take advantage of multiple cores.

The clock speed of a CPU is another important factor in its performance. The clock speed refers to the number of cycles the CPU can execute per second, measured in gigahertz (GHz). A higher clock speed means the CPU can execute more instructions per second, resulting in faster overall performance.

Next Steps:

1. Read through this short section on CPUs, part of a longer course at Khan Academy.

Further Reading:

• Other glossary entries: Hardware
• Elsewhere on the internet: CPU (Wikipedia)