fusion

Introduction to the Fusion Operating System

Fusion is a hobbyist operating system designed for the x86-64 architecture and is implemented using the Nim programming language. The development journey of Fusion is meticulously documented at the website 0xc0ffee, offering insights into building and enhancing this OS.

Features of Fusion

Fusion boasts several implemented features critical to modern operating systems:

• UEFI Bootloader: This component is essential for initializing the hardware and launching the Fusion kernel from a modern firmware interface.

• Memory Management:

  • It supports a single address space.
  • Features a physical memory manager and a virtual memory manager.
  • Operates with a higher half kernel, which helps execute the operating system kernel from high virtual memory addresses.

• Task Management:

  • Capable of handling both kernel and user mode tasks.
  • Supports preemptive multitasking.
  • Employs priority-based scheduling to manage task importance.
  • Includes an ELF loader for executing compiled files.

• System Calls:

  • Equipped with a system call interface.
  • Utilizes the SYSCALL/SYSRET instructions to facilitate user and kernel mode transitions.
  • Features a user mode library to assist in running user-level applications.

• Inter-process Communication (IPC):

  • Offers synchronization primitives for coordinating tasks.
  • Includes channel-based IPC for structured message passing between processes.

• Hardware Integration:

  • Manages timer interrupts and performs PCI device enumeration.
  • Comes with a Bochs graphics adapter driver for display support.

Planned Features

Future developments aim to expand Fusion's capabilities with features like:

• Capability-based security systems to enhance protection.
• Event-based task state machines for more flexible process management.
• Demand paging for improved memory efficiency.
• Advanced disk I/O and file system support.
• Integrated keyboard and mouse input, a command-line shell, and a graphical user interface (GUI).
• Networking functionalities to connect with other systems and networks.

Building and Running Fusion

To build Fusion, one must have the following dependencies:

• The Nim programming language, essential for compiling the OS.
• LLVM tools (including clang and lld) for handling low-level language constructs.
• The Just command runner to simplify the build process.

Building Fusion is straightforward with the command:

just build

To run Fusion, use QEMU, a versatile emulator that simulates various hardware environments. With QEMU installed, you can launch Fusion using:

just run

Licensing

Fusion is open-source and licensed under the MIT License, allowing users to freely use, modify, and distribute the software.

Through continuous development, Fusion represents a blend of innovation and learning in the domain of operating systems, offering a unique opportunity for enthusiasts to explore OS design and implementation.