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Follow a keystroke from the keyboard through the CPU, memory and storage, and see where the operating system sits.
By the end of this lesson
A free account unlocks the full lesson, the five-question knowledge check, progress tracking, notes and the completion certificate.
Press a key and a character appears. It feels instant and simple. Underneath, a small factory has coordinated power, memory, storage and several layers of software without asking you for anything.
This lesson follows that path. You do not need to repair a motherboard afterwards, but you do need to know where each layer sits, because attacks and defences live at specific layers.
The CPU executes instructions. Its speed is not the whole story: how many cores it has, how much cache it holds, and what it is waiting on often matter more.
RAM is working memory. It holds the programs and data the CPU is using right now. It is fast, relatively expensive, and volatile: when power goes, its contents go too.
Storage (an SSD or hard drive) keeps data when the machine is off. It is much slower than RAM, so the OS constantly moves what is needed into memory.
The motherboard and bus connect everything and carry data between components. Peripherals such as keyboards, displays and network adapters turn the machine into something usable.
Before an operating system exists, the machine needs to know how to start. That job belongs to firmware, low-level software stored on the hardware itself.
On modern PCs the firmware is UEFI (Unified Extensible Firmware Interface), which replaced the older BIOS. It initialises hardware, finds a boot device and hands control to a bootloader.
Firmware is a security boundary. If an attacker can modify it, the compromise can survive reinstalling the operating system. That is why firmware updates and Secure Boot matter: Secure Boot checks the signature of each early boot stage before running it.