The document discusses the different components that make up a computer system. It begins by defining a computer as an electronic device that can store and process data according to programmed instructions. It then describes the main components of a computer which include hardware, software, and firmware. The document goes into detail about the various hardware components such as the central processing unit, memory, mass storage devices, input devices like keyboards and mice, and output devices like monitors and printers. It also discusses different types of software and input/output peripherals.