TBS Kernel

Overview

TBS is a hobby operating system kernel developed as a learning project to explore low-level system design and operating system internals.

The project focuses on implementing fundamental OS components from scratch in order to better understand how modern systems work. While still experimental, the kernel has grown beyond a minimal prototype and now includes several core subsystems such as preemptive multitasking, terminal interfaces, a basic window compositor, and virtual memory management.

The system is intentionally kept simple and readable so that new features and ideas can be explored without excessive complexity.

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Features

Current functionality implemented in the kernel:

• Preemptive Multitasking
  A timer-driven scheduler allowing multiple tasks to run concurrently. Round robin style.

• TTY Subsystem
  Basic terminal interfaces used for system interaction and debugging.

• Window Compositor
  A minimal graphical compositor capable of drawing and managing simple windows. Runs in VGA text mode.

• Memory Management

  • Identity-mapped paging
  • Basic virtual memory setup
  • No ring userspace seperation for simplicity.

• RAM Filesystem (Work in Progress)

  • An in-memory filesystem used during early system development.
  • Loads external .img file using grub modules, mounts it to the ram filesystem.

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Architecture

The goal for TBS is to follow a micro-kernel architecture, executing as much as possible in ring 3. The kernel isn't a microkernel yet. Its in its early stages of development.

Paging is enabled for memory management and hardware-enforced protection. The system currently uses identity-mapped memory, and a bump allocator for early initialization.

While the kernel is currently monolithic, the design leaves room for potential future separation between kernel and userspace as the system evolves.

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Project Goals

The primary goals of this project are:

• Learn practical kernel development
• Understand memory management and scheduling
• Build fundamental OS components from scratch
• Experiment with system design decisions

The project prioritizes learning, experimentation, and simplicity over completeness or production readiness.

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Roadmap

Planned next steps for the system:

• Improve and stabilize the RAM filesystem
• Implement a disk-based filesystem
• Add a minimal C runtime environment using musl libc
• Port TinyCC (TCC) to allow compiling programs directly inside the OS
• Expand userspace support
• Use graphics framebuffer instead of VGA for more complicated graphics.

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Building

Requirements

• GCC cross-compiler (e.g. x86_64-elf-gcc)
• NASM
• Make
• QEMU

Build

make

Boot Process

A simplified overview of the system startup sequence:

• Bootloader loads the kernel
• Kernel initializes basic hardware and memory
• Paging is enabled
• Bootloader modules are parsed
• Filesystem gets mounted.
• Scheduler and multitasking are initialized
• Core subsystems (TTY, compositor) start
• System enters the main kernel loop

Project Structure

wip

Screenshots

below is a screenshot of the kernel running the simple compositor. a few commands are displayed such as directory manipulation and pci enumeration