Booting process by AROS

AROS boots in several stages. 

On a PC, the process is roughly: 
firmware → bootloader → AROS kernel → startup scripts → graphical desktop. 

How AROS OS boots on a PC 1. The PC firmware starts first When the computer is switched on, the firmware starts before AROS.

Depending on the machine, this is usually:
BIOS on older PCs
UEFI on newer PCs

The firmware initializes basic hardware such as CPU, memory, keyboard, graphics, and storage controllers. 

Then it looks for a bootable device, for example: 
hard disk
SSD
USB stick
CD/DVD
ISO image in a virtual machine

The boot device is selected 

The firmware checks the boot order and searches for a device that contains boot code. 

For AROS, this may be: 
an installed AROS hard disk
an AROS live CD/ISO
a USB stick with AROS
a virtual hard disk in a VM

If no bootable AROS device is found, the PC may show an error or continue to another operating system. 

The bootloader is loaded 

After the firmware finds a valid boot device, it loads a small boot program. This bootloader has one main task: load the AROS kernel and the required early system files. On x86 PCs, AROS usually needs a boot mechanism that can start its kernel from the selected disk or ISO. In many installations, the installer sets up this boot part automatically. 

The AROS kernel starts 

The kernel is the central part of the operating system. 

It begins to initialize: 
memory management
task scheduling
interrupt handling
basic hardware access
device detection
system libraries
low-level operating system services

At this stage, AROS changes from “just being loaded” into a running operating system. 5. Drivers and devices are initialized AROS then tries to detect and use the available hardware. 

This may include: 
graphics card or VESA display mode
keyboard
mouse
hard disk controller
CD/DVD drive
USB controller, depending on support
network adapter, if supported
audio hardware, if supported

On real PCs, hardware compatibility is important. In a virtual machine, AROS usually sees virtual hardware instead of the real host hardware. 

Volumes and assigns are created 

AROS uses Amiga-like volume names and logical paths.

Typical examples are: 
SYS: — the main system volume
C: — command directory
S: — script directory
Libs: — libraries
Devs: — device drivers
Prefs: — preferences
ENVARC: — permanent environment settings
ENV: — active environment settings
RAM: — temporary memory disk

During boot, AROS prepares these locations so programs and scripts can find the files they need. 

Startup scripts are executed 

After the kernel and basic system are running, AROS executes startup scripts. The most important startup file is usually: S:Startup-Sequence This script starts important system commands and prepares the desktop environment. 

It may do things such as: 
set environment variables
create assigns
load system components
start background services
prepare the graphical environment
run additional user startup commands

Another important file may be: S:User-Startup This file is normally used for user-specific additions. For example, it may contain extra assigns or commands for installed software. 

Preferences are loaded 

During startup, AROS loads saved preferences. Many permanent preferences are stored in: ENVARC: At boot time, they may be copied or applied to: ENV: 

This can affect: 
screen mode
fonts
input settings
locale and language
pointer appearance
audio configuration
Wanderer behavior

This is why saved preferences can change how AROS looks and behaves immediately after boot. 

The graphical system starts 

After the lower-level system is ready, the graphical user interface starts. 

Important parts include: 
Intuition — the Amiga-style windowing and user interface system
graphics system components
screens and windows
desktop-related services

Once the graphical layer is working, programs can open windows, screens, requesters, and menus. 

Wanderer desktop appears 

Finally, AROS starts Wanderer, the desktop environment. 

Wanderer shows: 
disk icons
drawer icons
program icons
desktop windows
mounted volumes such as SYS: and RAM:

At this point, the user can interact with AROS graphically. 

Typical first actions after boot are: opening SYS:
opening Prefs:
starting programs
checking screen mode
opening the Shell
browsing files with Wanderer

Booting from live ISO vs installed system 

Live ISO boot When AROS boots from an ISO or CD, most system files are loaded from the optical image. 

This is useful for: 
testing AROS
installing AROS
checking hardware compatibility
repairing or inspecting an installation

Changes may not be saved permanently unless another writable disk is used. Installed hard disk boot When AROS boots from an installed hard disk, it loads the system from the installed SYS: partition. 

This is better for daily use because: 
preferences can be saved
programs can be installed
files can be stored permanently
startup scripts can be customized
the system boots without the ISO

Typical boot sequence in simple form 

A beginner-friendly overview looks like this: 
Power on PC↓BIOS/UEFI starts↓
Boot device is selected↓Bootloader starts↓
AROS kernel is loaded↓
Drivers and devices are initialized↓
SYS:, RAM:, C:, S:, Libs:, Devs: and other assigns are prepared
S:Startup-Sequence is executed↓Preferences from ENVARC: are loaded
Graphical system starts
Wanderer desktop appears 

Common boot problems 

AROS does not start at all Possible causes: 
wrong boot order
disk or ISO is not bootable
installation was incomplete
bootloader was not installed correctly
unsupported firmware or hardware configuration
AROS starts but stops during boot Possible causes: missing system files
damaged S:Startup-Sequence
wrong assigns
missing libraries
incompatible drivers
AROS boots but the desktop does not appear Possible causes: graphics mode problem
Wanderer cannot start
missing GUI components
broken preferences
startup script error

AROS boots from ISO again after installation This usually means the ISO is still first in the boot order. Remove the ISO or set the hard disk as the first boot device. Short summary AROS booting on a PC starts with the BIOS or UEFI, which loads a bootloader from the selected disk, ISO, or USB medium. The bootloader loads the AROS kernel. The kernel initializes memory, devices, drivers, volumes, and assigns. Then AROS runs startup scripts such as S:Startup-Sequence, loads preferences from places like ENVARC:, starts the graphical system, and finally opens the Wanderer desktop.