# Dependencies

In this section, you will find the dependencies required to build the MOS kernel and userspace.

# 1. Build Tools

CMake 3.20 or later
Ninja or Make, Ninja is recommended for faster builds
Python 3+, required for the Kconfig tool and system call generator

You can install these tools using your favorite package manager.

# 2. Architecture Specific Dependencies

Generic: Generic Architecture Dependencies lists the dependencies for all architectures.
x86_64: please refer to the x86_64 dependencies for the dependencies.

# 3. MOS Toolchain

You will need a cross-compiler toolchain to build the kernel and userspace for MOS. The toolchain must be specifically for the target architecture, which can only be x86_64 at the moment.

Suppose that $ARCH is the target architecture, e.g. x86_64, you will need the following packages:

mos-sdk for CMake support for the MOS operating system.
$ARCH-mos-binutils and $ARCH-mos-gcc for the cross-compiler toolchain, which includes the assembler, linker, and compiler.
$ARCH-mos-mlibc-headers or $ARCH-mos-mlibc for the C standard library headers and/or implementation.

# 3.1. Choosing between `mlibc-headers` and `mlibc`

mlibc-headers is a package that only contains the headers of the C standard library, which is useful for building the kernel only.
mlibc contains both the headers and the implementation of mlibc, this is required for building the userspace applications.

# 3.2. Installing the Toolchain

MOS uses pacman as its package manager, which is the one used in Arch Linux, MSYS2 and other distributions. The pacman package manager is simple and easy to use. The packaging scripts are written in bash, making it easy to create and maintain packages.

You will be able to find these packages from the MOS Binary Repository, simply add the following repository to your pacman.conf:

# Packages are not signed yet
[mos]
SigLevel = Optional
Server = https://mospkg.mooody.me/$arch

Then you can install the packages using:

export ARCH=x86_64 # or any other supported architecture
pacman -S mos-sdk $ARCH-mos-binutils $ARCH-mos-gcc $ARCH-mos-mlibc

This option is more useful if you want to customize the toolchain, or if you want to build the toolchain for an unsupported architecture.

The toolchain is built using the makepkg tool, which is part of the pacman package manager.

You can find the packaging scripts for the toolchain in the MOS Package Repository.

# 3.3. Using the Toolchain

Once installed, the libraries will be available at /opt/$ARCH-mos while the cross compilers will be installed to the standard locations, e.g. /usr/bin/$ARCH-mos-gcc.

# 4. After Installation

No further configuration is required to use the toolchain, once you have installed the packages, you can start configuring and building MOS.