In the easiest of terms, a computer is a machine that can compute. The extremely capable and versatile machines that we know as computers today had humble beginnings; to understand what a computer is, we must know its origins.
Some of us may have read in school that abacus, which was initially used for counting purposes and arithmetic tasks, may be considered as the earliest form of computing devices. While an abacus may help to keep count, it certainly is not the computing device that we are familiar with today. Charles Babbage, whom you may know as the father of computer, invented the first mechanical computer. The machine had in input, an output, and an arithmetic logic unit along with an integrated memory. His machine, the Difference Engine, created the framework that modern computers are based on. Modern computers can be classified into three generations.
First generation of computers were built using vacuum tubes for processing. These machines were huge, weighed tons, had no operating system and could perform only a single task at a time. For example, ENIAC had 18000 vacuum tubes and weighed 30 tons.
The second generation of computers used transistors instead of vacuum tubes. These were way more reliable and versatile. Machines like UNIVAC 1, IBM 650 and 700 series were notable machines of this era.
We are using the third generation of computers today. These machines use Integrated Circuit (IC), they are power efficient, compact, reliable, versatile. These are the computers we know and love. Our desktops, laptops, phones, all are examples of third generation computers.
So, this was a simple introduction to the history of computer. Now, how modern computers actually work? It is simple. A user, i.e. you, gives input, the machine processes that data, and gives an output. For example, let’s say you are reading this on a computer. You must have clicked your mouse, typed something on your keyboard. Or, if you are using a mobile device, you are touching your screen. Your touchscreen, keyboard, mouse, everything is input for your computing device. Whenever you press something, an instruction or a set of instructions have been sent to the processing unit, i.e. processor, of your device. Then your device processes the information or follows the instructions, and produces a result. You see that result through your screen or hear that through your speakers. Let’s look at a simple example. You press A on your keyboard and it shows up on your screen. When you press the key ‘A’, the computer is being told that the user has pressed ‘A’ and it has to display the correct response, then the computer shows A on your screen. This is a very simple example of input, processing, output.
An input device is something that you use to give your device data; keyboard, mouse, mic, touchscreen etc are examples of input device: and the computer gives you results through output devices, such as display, speaker, printer, etc.
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