Firmware stage 🧠

BIOS and UEFI (simple explanation)

Firmware is the first “brain” that wakes up your computer. It lives on a chip on the motherboard. Its job is to check basic hardware and then hand control to the next runner.

Hardware Firmware Boot Loader

What BIOS is

BIOS = Basic Input/Output System
Old-style firmware used for decades
Does basic checks, then looks for something to boot
Usually works with older “legacy” boot style

Click to see a simple analogy ▼

BIOS is like an older security guard who:

checks the doors (RAM, keyboard, disks)
then says “OK, start the store”

What UEFI is

UEFI = Unified Extensible Firmware Interface
Modern firmware replacing legacy BIOS on most PCs
Understands modern disks and has better features
Works well with security features like Secure Boot

Why modern systems use UEFI ▼

UEFI is more flexible and modern:

can boot from large drives more easily
supports more structured boot files
often boots faster
stronger security options

Where firmware is stored (BIOS chip)

Firmware is stored on a small non-volatile memory chip on the motherboard. It stays there even when the PC is off.

Hover these terms: firmware chip, startup checks.

Legacy BIOS vs UEFI (comparison table)

Feature	Legacy BIOS	UEFI
Age	Older	Modern
Boot method	Legacy boot style	Boots using structured boot files
Disk support	More limited	Better support for modern large disks
Security	Basic	Supports Secure Boot and stronger options
User interface	Often text-like	Often graphical and mouse-friendly

Visual handover diagram (click the boxes)

⚡ Power On

Hardware wakes up

🧠 BIOS/UEFI

First code that runs

🚀 Boot Loader

Next runner

Click each box. This is the “handover” (control transfer).

Next: TPM 🔒 Back: Roadmap