How Does A Computer Work?

This post will explain the work process of a Computer and its most common tools:

• Microprocessor
• RAM
• ROM
• Operating System
• HDD
• Graphics Card
• Screen

Step by Step:

When we sit at a Personal Computer (PC) we are very likely to be using an Operating System which allows us to access all the features of our unit. This OS is using something called G.U.I. or the Graphical User Interface which was the first step of personalizing the Computer. GUI takes whatever is processed by the microprocessor and visualizes so that we can understand what is happening by just looking at the screen. But what actually happens when we for example start an application on the PC?

Pinball Application on the Windows XP OS

Step 1: Input

Since the beginning of PCs we have used the mouse and keyboard to input information and select from a vast variety of options. This has not changed until today. Let's say in this case I want to start the very known Windows Application, Pinball. I use the mouse and select the application commanding the computer to start it. At this stage the OS tells the microprocessor to go to the HDD (Hard Disk Drive) and find the application i have selected. 

Step 2: Launch

At this stage the microprocessor loads all the data that will be needed for the application onto the RAM memory. The RAM memory is a storage space that stores files only temporary but can be accessed much faster than the HDD. Background processes also run on the RAM. Once the necessary files are loaded onto the RAM the Microprocessor can process the needed data in order to use the application. 

Step 3: Use

The application data is now on the RAM and the Microprocessor has processed its first appearance, or launch screen, and passed it on to the Graphics Card. This device then Converts the data it just received and passes it on through a variety of different possible Ports (VGA, HDMI, S-Video) to the Screen. We then see the the launch screen on the computer screen an are able to interact with it with the help of further input by using the mouse or keyboard. 

In the case of Pinball we wan to play the game in "full screen mode" so I press the "F4" button on the keyboard. The OS sends this information to the microprocessor that then checks the data on the RAM what this action does an receives and answer that it changes the appearance of the application from "window mode" to the full screen. So it sends this command to the graphic card that then enhances the picture on the screen an displays the game on the whole screen. 

Each further action has to go through the exact same loop and the outcome always depends on the kind of input that was given the OS, Microprocessor,... and so on. 

On a last note you may want to know that all these devices communicate with the same language which is known as the binary code, a mix of 1s and 0s. Each combination of those has a different meaning and is translated into a different command. 

Visualized example of a Binary Code