Security roles and how a computer boots
What I learned about three common cybersecurity roles, the main parts inside a computer, and what happens between pressing the power button and seeing the desktop.
This week I covered two topics: the different roles in cybersecurity, and how a computer actually works from the inside. Here's what I learned.
Three roles in cybersecurity
Penetration tester. Pen testers look for vulnerabilities and try to break in, with permission, before a real attacker does. Their job is to show where the weak points are so they can be fixed.
SOC analyst. SOC analysts work in a Security Operations Center. They use tools that raise alerts on suspicious activity, investigate each alert to decide whether it's normal or malicious, and take action if it turns out to be a real threat.
Security engineer. Security engineers design the protection plan and build it into the systems, making sure devices and networks are set up securely from the start.
One way I think about it: the pen tester attacks, the SOC analyst watches and responds, and the security engineer builds the defenses.
The parts inside a computer
- Motherboard: the main board that connects every other component together.
- CPU: the processor that runs instructions. The "brain" of the computer.
- GPU: the graphics processor that handles images, video, and other heavy parallel work.
- RAM: fast, temporary memory for whatever is running right now. It's cleared when the power goes off.
- Storage (SSD / HDD): where files and the operating system are kept permanently. SSDs use flash memory and are much faster; HDDs use spinning disks.
- Power supply (PSU): converts power from the wall into what the components need.
- Network adapter: connects the computer to a network, wired or Wi-Fi.
What happens when you press the power button
- Power on: the power supply sends power to the motherboard and components.
- BIOS/UEFI wakes up: the firmware on the motherboard starts first.
- POST (Power-On Self-Test): the firmware checks that the key components are present and working.
- Boot order: it looks through its boot priority list to find a drive with an operating system.
- Load the OS: the bootloader loads the operating system from storage into RAM.
- Hand over control: the operating system takes control of the computer, and you get your login screen.
Understanding this helps with security too. For example, protecting the boot process (like Secure Boot) stops malware from loading before the operating system even starts.