The hardware refers to all of the components or physical devices that are made of computer. A computer is not only one single device, but a system of devices that all work together.

The computer system consists of the below major components.

• The central processing unit (CPU)
• Main memory
• Secondary storage devices
• Input devices
• Output devices

The central processing unit is the main part in the computer. Computer could not run any software without CPU. CPUs are small chips called as microprocessors.

Main memory is known as random-access memory, or RAM. It is called this because the CPU is able to quickly access data stored at any random location in RAM. RAM is a volatile type of memory that is used only for temporary storage while a program is running.

Secondary storage is a type of memory that can hold data for long periods of time, even when there is no power to the computer. Programs are stored in secondary storage memory and loaded into main memory as needed. For example, Hard disks, external storage dives etc.

 Input is any data the computer collects from people and from other devices. The component that collects the data and sends it to the computer is called an input device. The input devices are the keyboard, mouse, scanner, microphone, and digital camera. Disk drives and optical drives can also be considered input devices because programs and data are retrieved from them and loaded into the computer’s memory.

Output is a data the computer produces for people or for other devices. The data is sent to an output device, which formats and presents it. The output devices are video displays and printers. Disk drives and CD recorders can also be considered as output devices because the system sends data to them in order to be saved.