Computer hardware refers to the physical components that make up a computer system. It includes processing components like the CPU and memory, as well as input devices, output devices, and storage devices. The CPU fetches and executes instructions from memory. Memory comes in different types, including cache memory, RAM, and ROM. Input devices like keyboards and mice allow entering data. Output devices like monitors and printers display or print the output. Storage devices such as hard drives and optical discs store data for later use.