PawsOS

A simple OS, which has various features:

• IRQs
• ISR
• GDT
• Ports
• Serial ports (COM1, COM2, COM3, COM4)
• Keyboard (Qwerty and azerty)
• Multiboot (Can be booted by GNU Grub)
• RTC (Real Time Clock)
• ACPI (Can shut down your computer)
• Paging
• Memory manager
• And more.

This OS is based on cfenollosa/os-tutorial and some other OSes with GPL compatible license.

Directory structure

┌───boot # Boot files, includes GDT, Multiboot headers and Boot file.
├───cpu # Files related to the CPU, like ports or interrupts.
├───debug # Files used for debugging purposes.
├───drivers # As the name states, are drivers like the keyboard or screen driver.
├───fs # Files related to File Systems and hard disks.
├───iso # Folder created after successful build. Includes bin file (The OS) and grub.cfg (Grub configuration file).
│   └───boot
│       └───grub
├───kernel # Files directly related to the OS/kernel, like the kernel panic or the kernel itself.
├───libc # A small LibC used by various components on the OS.
└───os-image.iso # Bootable file created after successful build. Includes the OS and the bootloader (Grub).

Building

Firstly, you need to build an i386-elf-gcc cross-compiler, you can get build instructions here (WARNING: The build process of your cross-compiler can take various hours depending on your Hardware).

There are various GCC versions available, here is a compatibility list:

• [✔] GCC 11.1.0
• [✔] GCC 10.2.0
• [✔] GCC 8.4.0
• [❌] GCC 4.9.1

Then, you will need the Grub bootloader and the image builder which are generally distributed on 2 different packages:

• grub-pc-bin
• grub-mkrescue

You can get that packages from your package manager.

And get CMake from your package manager or download it manually.

Finally, you will need the NASM compiler, you can get it from your distro package manager.

Add all these to your operating system path.

Then build following this steps:

1. Create a directory called build in the source directory.
2. Change to that directory.
3. Run cmake -DCMAKE_BUILD_TYPE=Release ...
4. Run cmake --build . and wait until build finishes.

You will get two files after a successful build:

• os-image.elf
• os-image.iso

You can use the os-image.elf file for debugging purposes.

Not only that, but you can use the os-image.iso file to boot using a bootloader (GNU Grub by default, but you can use another Multiboot compliant bootloader).

The default output format is elf32-i386.