What is computer?

Good evening! This is TT who met my boss for the first time in a year last week!
Well, I like remote work because it’s more comfortable, but it’s nice to work in the same space for the first time in a while.

Let me talk about IT today as well!

In the first place, what do you think of when you think of IT?
In my case Computers are repsentative of IT!

The range is extremely wide when wrapped up in a computer, but as a Game Boy generation, game machines and personal computers have been familiar to us since we were young.

I think many people think that “IT or digital things are doing business with computers.” So today, I would like to unravel the question “What is a computer?”.

Definition of computer

If you look up the Iwanami Japanese dictionary on your computer, you will see the following.

1. Calculator.
2. Especially, counting type digital calculator.

You can see 1. is like number cruncher, but 2. is gibberish, isn’t it?

Admitting 2. is gibberish, but what I mentioned at the beginning as a synonym for IT corresponds to this 2.

The Japanese dictionary I mentioned earlier is kind and expained additionally on counting type digital calculator as following;

A computer that consists of control unit, arithmetic unit, storage unit, and input / output unit, and can perform complex data processing electronically at high speed by a program.

Being more specific. A computer is a machine in which software called a program commands hardware to perform calculations.

A computer is made up of various devices. In the dictionary, it was divided into control unit, arithmetic unit, storage unit, and input / output unit. However input / output unit is devided to input unit and output unit, and these 5 units are called 5 major units for computer. In the next section, let’s see roles of each unit one by one.

Roles of 5 major units

The general role of the 5 major unit is described in the diagram below;

Unit	Typical equipment	Roles
Control unit	CPU（Central Processing Unit)	Control computer overall by interpreting command from program
Arithmetic unit	ALU（Arithmetic and Logic Unit）	Calculate within computer
Storage unit	・Memory（Main storage） ・CD-ROM（Auxiliary storage）	Store necessary program and data for operating computer
Input unit	Keyboard/Mouse/Scanner	Input data computer
Output unit	Display/Printer	Output data computer

Let’s see how it works one by one.

1. Control unit(CPU)
   Control unit is a brain. It manages overall behavior of computer based on information sent from other units. Program is read from memory (main storage) and requested to arithmetic unit for calculation, or output to display (output unit).
2. Arithmetic unit (ALU)
   Communication within and between computers is based on calculation results. Arithmetic unit performs calculation processing in computer. It calculates data received from the control unit and sends result to memory.
3. Storage unit
   If you do not save calculation result of data in the computer, calculation result will be lost. Storage unit plays an active role in such situations. Storage unit can be generally divided into two types: main storage and auxiliary storage.
   Main memory can only store data temporarily because the data processing is fast. Therefore, if you turn off your computer, its contents will be discarded. You need to take care for using it.
   On the other, auxiliary storage can store data for a long period. Therefore, the contents are saved even if computer is turned off. However, data processing speed is slow, so overall computer’s calculation speed will slow down if only auxiliary storage device is used. Main storage device and the auxiliary storage device complement each other.
4. Input unit
   Input unit is a device used by a computer to enter information. Recently, there are various input methods such as voice and image, but we will cooperate after converting data into a form that can be saved in memory. This is an interface between computers and people.
5. Output unit
   Finally, output unit shows calculation results in computer in a human-visible form. This unit may not be necessary for non-personal computers, but what you want to achieve with an input unit will eventually be realized with an output unit.

The above are the roles of the five major computers. Even though it’s a single computer, various units are doing their bests inside. I persnally had an image of “craftsman” working silently and individually on a computer. However, when I studied this time, I felt that computer was working in team play, and felt a sense of sympathy.

Conclusion

That is general part of computer. What did you think? I am happy if you could share comment on what you felt for computer. In this article, the main points are following two;

1. Computer is composed by Control unit, Arithmetic unit, Storage unit, Input unit and Output unit.
2. These units are called 5 major unit for computer.

If you take a closer look at computer, it is considerably deep, so I will keep up with the details! Thank you for reading 🙂

1,362 days until 2025