Serra - a boot manager under construction <3

 

 

Serra is an open-source x86 boot manager currently under construction.

My goal here is to develop a universal and reliable boot manager that works across different systems, with a focus on code quality and user experience.

It's currently a work in progress - see the roadmap below - but my goal is to have it ready by later this year.

 

An older write-up of Serra's boot process

 

Build process

Important

You'll need to do this on Linux (or an environment like WSL); other operating systems aren't supported.

In order to build Serra, you will need the following tools:

This project uses the C23 standard, which is fairly new, so please make sure you're using the latest version.

• Assemblers and (cross) compilers

• • nasm, or any other compatible x86 assembler;
• • i686-elf-gcc, or any other x86 native ELF compiler;
• • • This will be used to build Boot/Legacy, and must have full C23 support (GCC 15+, Clang 19+);
• • x86_64-elf-gcc, or any other x64 native ELF compiler;
• • • This will be used to build Common/, and must have full C23 support (GCC 15+, Clang 19+);
• • x86_64-w64-mingw32-gcc, or any other x64 Windows/PE compiler.
• • • This will be used to build Boot/Efi, and must have partial C23 support (GCC 13+, Clang 16+);
• • • On Ubuntu 24.04+, you can use sudo apt install binutils-mingw-w64 gcc-mingw-w64.

• Build tools

• • make (GNU make), for the build system itself;
• • dd, mtools and sfdisk, to compile the final disk image.

• Other utilities (optional)

• • qemu or bochs, to run the final disk image;
• • gdb, to debug the boot manager;
• • ovmf, to use as UEFI firmware.

Understandably, this isn't the most straightforward setup, and you will need to make your own cross compilers (this guide is pretty useful), but once everything is done, it should be as easy as running make all.

Building and running the boot manager

Configuring the boot manager

This is still a work-in-progress, but you can configure how Serra is built and configured in makefile.config > Build Options.

Building the boot manager

• make clean: Clean all leftover files (.o, .bin, .elf, .img, etc.);
• make compile: Compile any remaining files;
• make all: Build everything;

Running the boot manager

• make run: Run with QEMU;
• make runbochs: Run with Bochs;
• make runefi: Run EFI with QEMU;
• make rungdb: Run with QEMU using the GDB debugger;
• make runkvm: Run with QEMU using the KVM emulation layer;
• make runint: Run with QEMU showing exceptions.

 

Roadmap

• Finish implementing the disk subsystem, in Kernel/Disk;

• • Implement handlers for the EFI Block and Disk IO protocols (EFI_BLOCK_IO_PROTOCOL and EFI_DISK_IO_PROTOCOL respectively);
• • Unify both the BIOS and EFI handlers into one unified disk read function;
• • Work on filesystem drivers, and create a VFS.

• Add the actual boot manager functionality (support for boot protocols);

• Create simple human interface drivers (keyboard, mouse..);

• Create a simple console user interface / menu.

 

Disclaimer

This project has been released under the MIT license. For more information, please refer to the accompanying license agreement. <3

(last updated on July 30th 2025)