How software works in 4 steps

(I would like to thank professor Mrs. Natasa Milic-Frayling for explaining the functioning of software - the backbone of our digital information society - so well to me).

We can read books with our eyes but to read digital files we need special “glasses”. These glasses are software applications. Software is created by humans to instruct their machines (computers) to do what the application is supposed to do, like enable us to write, calculate, draw, play a game, etc. But how does software work? How do we get from an idea “what the computer needs to do” to having an application, installed on our computer, that we can use to do the job?

Step 1

First a human (a programmer) writes instructions in the form of a source code. These instructions are written in a well-defined and highly structured form that is still human readable. The source code is written in a textual form. This is the basis for the software and it looks like this:

Source code: how a programmer formulates what the computer needs to do, using human language in a special and logical way.

Step 2

At this stage the code cannot be understood by computers, which only understand machine code – the computer’s language. So the source code is translated into machine code using a compiler. The resulting machine code looks something like this when displayed to humans:

Compiled code: machine language (commands) a computer can understand.

 

Step 3

The next step is called linking. This is where all the pieces (components) of the compiled code are linked together. Examples are components that enable the program to manage memory, accept input from the keyboard or mouse, display information on the computer monitor, etc. All of that needs to be correctly connected, to work together. The end result of the linking phase is the famous .exe file (short for “compiled executable”) that we are all familiar with. It’s the file you have to download to make a new software application work on your computer, like in this picture: 

The "magical" .exe file that will bring the software to life on your computer so you can use it.

Step 4

To “communicate” the .exe file to the computer it needs to be installed. The installation is executed by an installer, which is an application that is often called setup.exe. The installer contains all the information needed to set up the application on your computer. It “tells” the computer where all the components of the software are, and how to run them. For example, the installer may put a button on the start menu so that you can easily start the application. Or it configures the application to your own preferences in terms of language, colors, etc..

The end result is an installed software application that you can click on and use, like Microsoft Word or Excel, for example.

And there you go!

The end of the process: the software up and running as we know it.

 (Twitter: @Oosterenvan, #UnescoPERSIST)