The four main components of a computer system are input devices, output devices, processing devices and the storage devices used to store data within the computer system. These are the hardware components of a computer system; software is a set of digital instructions for the computer stored in the memory.
The input devices are used to enter data into the computer system. They include the keyboard and mouse. Once data is entered, they convert it into an internal form that can be processed by the central processing unit. The output devices are used to present the processed information to the user. They include the monitor and speakers. The processing devices perform the actual processing of the data. The main processing device is the processor. The storage devices include the RAM and hard disks. They store information within the computer system.