Computing Devices are the electronic devices that take inputs, process the inputs and then calculate results from the inputs. One of the most common computing devices is computer which we all know about it. Some of the computing devices use today are shown in the following figure. any electronic equipment controlled by a CPU, including desktop and laptop computers, smartphones and tablets. It usually refers to a general-purpose device that can accept software for many purposes in contrast with a dedicated unit of equipment such as a network switch or router. This is the vast field and it covers huge amount of devices today which we are using in one or another form and these devices ranging from simple Calculators, Printers, Digital Cameras, Mobile phones, Smart phones, PC Desktops, Laptops and many more. These all do the math calculations on the streams of binary digits (bits i.e. 0 and 1 ) and produce the results in different forms that we need. They simply take inputs from the users and process the inputs by doing calculations and then produce outputs. Let us take the example of a computer, we enter the inputs to the computer (like pressing the keys from the keyboard or clicking through the mouse), it processes them and produces the output data on the screen of the monitor in Bangladesh.