ChaOS

What is ChaOS?

ChaOS is a hobbyist x86 operating system written from scratch in C.

Features

• Legacy BIOS bootloader
• EFI bootloader
• Pre-emptive single CPU MLFQ multitasking
• PS/2 keyboard & mouse support
• VGA text & graphics
• ATA hard drive support
• Floppy support
• FAT file system support
• ELF user programs

Building

Note: It is recommended to have at least 1 GB of free storage

Clone the ChaOS repository

Note: Do not clone the repository into a path containing whitespaces

git clone https://github.com/Filiprogrammer/ChaOS.git

cd ChaOS

Setup tools

Debian

Install tools required to build, run and debug ChaOS.

sudo apt install nasm make qemu-system-x86 qemu-utils dialog gdb python3-tk

Get additional tools by either downloading the binaries:

wget https://github.com/Filiprogrammer/ChaOS/releases/download/v0.2.230727/chaostools-linux.tar.gz
tar -xf chaostools-linux.tar.gz -C tools

Or building them yourself:

sudo apt install wget build-essential file
tools/src/build-i686-elf-tools.sh
tools/src/GenFw/build.sh
tools/src/imgtools/build.sh
tools/src/mkdosfs/build.sh

Windows

To get the tools required to build, run and debug ChaOS on Windows, download the binaries here.

Or gather and build the tools yourself:

• QEMU
• Python3
• gdb
• make
• nasm

Cross-build the additional tools on linux:

sudo apt install wget build-essential file git automake autopoint bison flex libgdk-pixbuf2.0-dev gperf intltool libtool libltdl-dev python3-mako ruby unzip p7zip-full lzip libtool-bin python-is-python3

tools/src/build-i686-elf-tools-win.sh

sudo apt install gcc-mingw-w64-x86-64

tools/src/GenFw/build-win.sh
tools/src/imgtools/build-win.sh
tools/src/mkdosfs/build-win.sh

Build image

Linux

./build_image.sh hd

Windows

BUILD_IMAGE.BAT hd

VSCode

Press Ctrl + Shift + B

A select dialog will appear where the configuration to be built can be selected.

Once a configuration has been selected, the build process will start and progress can be tracked in the bottom terminal window. The build script might also ask which user programs to build.

Running

QEMU

To run ChaOS in QEMU, just use the following script.

Windows

QEMU_BOOT.BAT hd

Linux

./qemu_boot.sh hd

VirtualBox

To run ChaOS in VirtualBox, create a new virtual machine with at least 32 MB of memory and use the generated HDImage.vdi file as a virtual hard disk.

Debugging

Debugging in VSCode

To start debugging in VSCode, press Ctrl + Shift + D or click on the Run tab on the left. Then select a debug configuration and click the green arrow to start debugging.

During debugging, while the OS is paused, GUI tools can be launched to see, for example, which tasks are running and in which queue they are. To use that, simply type -exec source ../../gdb_tasks_gui.py into the Debug Console.

Another graphical debugging tool would be a tool that can be used to inspect the heap of the kernel. This can be launched by typing -exec source ../../gdb_heap_gui.py into the Debug Console.