Phase 1.10
Firmware & The Boot Sequence
System software in ROM and the sequence of loading the OS.
Firmware
The low-level software permanently embedded in a hardware device.
- Storage: ROM, EPROM, or Flash.
- Purpose: Bridge between Hardware and the OS.
| Category | Software | Firmware |
|---|---|---|
| Scope | Broad application tasks (Apps/Games) | Specific to hardware control |
| Persistence | Stored on disk, loaded to RAM | Embedded in hardware chips |
| Interaction | direct user interaction | Limited / Background only |
| Updatability | Frequent (Weekly) | Rare / Critical risk |
The Boot Process
The sequence when you press power:
- POST (Power-On Self-Test): Check CPU, RAM, and essential chips.
- BIOS/UEFI Activation: Firmware loads basic hardware settings.
- Locate Bootloader: Search disk/USB for the Master Boot Record (MBR).
- Bootloader Execution: Runs code like GRUB or Windows Boot Manager.
- Kernel Loading: The core of the OS is loaded from Disk to RAM.
- Init System: Launches user services and the Login screen.
Types of Booting:
- Cold Boot: From a completely OFF state.
- Warm Boot: Restarting when the system is already ON (Reset).
Technical Terms Breakdown
UEFI
Unified Extensible Firmware Interface. Modern replacement for the legacy BIOS.
Embedded System
A purpose-built computer inside another device (e.g., washink machine firmware).
System Initialization
Setting initial hardware states and preparing the logic for the OS.
Kernel
The central core of an operating system with complete control over everything.