Before writing this article, I thought to myself, but why am I so often asked to describe how a computer works? There must be tons of articles that explain this?
Indeed, there are many, but I admit that by reading them I understand better. Indeed, most really go into detail by telling you about cores, PCI slots or even binary codes which makes it incomprehensible to the uninitiated.
I’m not saying I’m going to do better, but I’m going to try to do things differently by focusing only on the essentials and avoiding all too technical terms as much as possible.
The easiest way to understand is always a small drawing:
Here are the essential components of a computer (and still screen, keyboard and mouse could be removed).
I told you I was going to keep it simple! (I think that at the same time that I will have to write part 2 of this article by developing a little more).
Before looking at how it works, let’s now take a look at the role of each:
The hard drive is a piece of equipment that will allow data to be recorded. We can compare it to a notepad or school notebook where we would come to write and read the information we would like to keep. We will come back to that. (The hard drive is sometimes referred to as mass memory.) Data written to the hard drive remains even when the computer is turned off.
RAM is the computer’s (non-permanent) memory, we could compare it to our memory (yes, we don’t record everything for life!). This memory is erased when we turn off the computer.
And finally, the processor, also called CPU, is the brain. It is he who controls the whole and it is he who will calculate and process the various incoming or outgoing information.
These components are all inside the computer and rarely accessible. They are all plugged into a large electronic card the size of the computer: this card is called a “motherboard”.
Here is an example of a motherboard:
Keyboard and mouse, I won’t dwell on this, but be aware that we call this input peripherals. (I give the explanation on the concept of peripheral just a little lower). The information always goes from the periphery to the processor.
The screen is an output device. The information always goes in the direction processor towards peripheral. (for example, the printer is also an output device). (Be careful, the new touch screens are also input devices because information is given to the computer by tapping on the screen).
A device is as the name suggests something that is around. (think of the ring road around large cities). In computing we could say a piece of equipment connected to the computer. The keyboard and screen are around the heart of the computer (although they often come with, or even included in, laptops).
Role of a computer.
Before we talk about how it works, let’s talk a bit about the role and what we expect from it. If you have bought a computer, you are expecting something from it:
Surf the Internet,
Work (enter text, do calculations, …)
Save and sort your photos,
In fact, every time you do something yourself: you have to use software.
What is software?
A software (or program) is a file that contains a series of operations (or instructions) that your computer must perform.
Let’s take an example in everyday life and compare our software to working in a factory. You are a worker in a factory that produces parts, and your manager describes your job to you, which consists of:
Take part A from the box,
drill a hole in part A,
take part B in another box,
screw part A on part B,
if the 2 pieces fit correctly then
place the assembly of 2 parts A and B on the treadmill.
throw the 2 coins in the trash
end of work.
All your work is described in the instruction manual. This manual is written in a language you understand (better!)
You can compare the software to this instruction manual, everything is described there. As you can see, it is a series of operations and the work can take different directions by answering the different questions (in the example: “if the 2 pieces fit correctly then…”).
As for you, the software is written in a language understandable by the one who will perform the operations. And so in this case, the software is written in a language understandable by the computer. (This is binary code, a sequence of 0 and 1).
But developers (those who make software) do not write software with 0 and 1. They write in a development language, and a translator tool (compiler) will convert this language into 0 and 1)
And for your culture, to learn a new language, developers often start with a little program called “hello world”
Here is the list of instructions for this little program:
Display “hello world” on the screen,
Close the program.
It may seem ridiculous to you, but depending on the languages and especially when you are starting out, it is not always easy to do.