Context

This room covers the basic components of a computer system.

Trying to defend what you don't understand is like defending a castle you have never seen.

In this room, we will explore our "castle". We will cover what a computer is, its building blocks, and how they are connected. After completing this room, you will have a general idea of how the components of a computer system interact with each other to provide services to its users. Don't worry about too much technical jargon or depth; we'll take this nice and easy and focus on the fundamentals.

Starting hypothesis

Being able to recognize and understand the functions of various computing components.

Method / Used Tools

Inside a Computer System

Nearly every computer system, whether it is a laptop, a server, or even a smartphone, is built around the same fundamental components. Each element has a specific role, and together they form a coherent system capable of processing, storing, and transmitting information.

At the center of everything is the motherboard. It acts as both the skeleton and the nervous system of the computer. Physically, it holds all the critical components in place. Logically, it allows them to communicate with each other through circuits and buses. Without the motherboard, none of the internal components could interact.

The CPU (Central Processing Unit) is often described as the brain of the computer. It executes instructions, performs calculations, and makes decisions based on program logic. Every command you run, every application you open, and every script you execute in a pentesting context ultimately gets processed by the CPU.

Working closely with the CPU is the RAM (Random Access Memory), which acts as short-term memory. RAM temporarily stores data that the CPU needs immediate access to. For example:

• Running programs
• Open files
• Temporary computation results

RAM is fast but volatile, meaning its contents are lost when the system powers off.

For graphics and parallel processing tasks, the GPU (Graphics Processing Unit) plays a crucial role. Originally designed to handle visual rendering, it can also perform large-scale parallel computations. In cybersecurity, GPUs are often used in password cracking because they can compute hashes much faster than CPUs.

The HDD or SSD serves as long-term memory. This is where the operating system, applications, and files are permanently stored. Unlike RAM, storage devices retain data even when the computer is turned off. SSDs are generally faster than HDDs because they use flash memory instead of spinning disks.

Powering all of these components is the PSU (Power Supply Unit). It converts electrical power from a wall outlet into the appropriate voltages required by internal components. Without stable power delivery, the system cannot function reliably.