Inside a Computer System

Nearly every computer system that you can think of includes, in one way or another, the same building blocks. Each part has its own job, and together they make the computer work. Let's have a look at each of these building blocks.

Throughout this task, we will use a very relatable analogy: the human body. The image above shows the different PC components and its human counterpart. To learn more about each component, open the "Static Site" by clicking on the green "View Site" button below. The static site should open in split-screen view.

Now that the core components are installed in the computer system, it is time to boot up the system. We can compare this to how we wake up in the morning and do a quick check to see if everything is working. Only when everything is OK, do we get up and start our day. The image below shows the steps a computer system goes through before it shows you a working interface (in the form of an Operating System).

Step 1: Press the Power Button
When we press the power button on our computer system, a signal is sent to the PSU to allow power to flow. Imagine our body being powered off when we sleep. Once we wake up and receive oxygen, our body starts pumping blood and boots up.

Step 2: Firmware starts
Continuing our analogy from step 1, once the body has started up, our core components are up and running, but our brain is not yet conscious. Like our bodies, a computer system contains firmware that allows all its components to start up. The central system that manages this is called the Unified Extensible Firmware Interface (UEFI). Note: We will often see the term BIOS mentioned instead of UEFI. BIOS does the same as UEFI, but has mainly been replaced by UEFI

Step 3: Power-On Self Test
Now that our body is up and running, it is time to test if everything is functioning as it should. If something isn't, there will be some alarm signals. One of the routines that the UEFI loads is the Power-On Self Test, which tests if every required component is present, configured correctly, and functioning.

Step 4: Select Boot Device
Once our body is up and running, configured correctly and fully functional, our system searches for the location of our bootup routine to start our consciousness. In our computer system the UEFI holds an ordered list which prioritizes on which device to look first for the boot up routine for the Operating System.

Step 5: Initiate Bootloader
Now that our system knows the part of our brain where our consciousness is located, it initiates the "load routine" to start it. Our computer systems follow a similar process: On the selected boot device, the bootloader is initiated. This bootloader transfers the Operating System from the selected boot device to the Random Access Memory. Once the OS is transferred, the UEFI gives control over the different components to the OS.

Now that we know how a computer system boots, let's have a little exercise. Open the static site in this task by clicking the green "Static Site" button and follow the instructions to answer the question below.

We have covered the core components of a computer system and how it boots up. At the moment, you won't realize this, but further on, when learning cyber security concepts, you will often need to recall the function of each of these core components and how they interact with each other. The boot process is a very important concept later on, as it is sometimes targeted by hackers.

Now that we know the insides of a computer, the next step is to see how the different combinations and specializations of these components lead to diverse types of computer systems. Continue to the next room Computer Types (coming soon) to find out.