The jsix Operating System

Introduction

jsix is a custom multi-core x64 operating system being built from scratch, supporting modern [1] Intel or AMD CPUs, and UEFI firmware. It was initially created out of a desire to explore UEFI and to explore what’s possible with a microkernel architecture on modern 64-bit architectures.

Most of jsix is written in C++ (C++17, using LLVM), but you’ll also find some assembly (in NASM syntax) and Python for development tooling.

jsix can be found on GitHub, and is released under the terms of the MPL 2.0.

A note on the name

This kernel was originally named Popcorn, but I have since discovered that the Popcorn Linux project is also developing a kernel with that name, started around the same time as this project. So I’ve renamed this kernel jsix as an homage to L4, xv6, and my wonderful wife.

The name jsix is always styled jsix or j6, never capitalized.

Current Features

The jsix kernel is quite far along now, but the userland systems are still lacking.

  • Platform: amd64

  • UEFI bootloader

  • Multi-core & multi-tasking microkernel

    • Work-stealing SMP scheduler

    • Pluggable panic handler modules

  • Capability-style object-oriented syscall API

    • Custom IDL for specifying and documenting syscalls

  • Virtual memory based on sharable Virtual Memory Area objects (VMAs)

  • Kernel API library (libj6), also provides features built on kernel primitives:

    • Channels (async stream IPC) built on shared memory and futexes

    • Ring buffers via doubly-mapped pages

  • Custom libc

  • Runtime dynamic linker

  • Init service

    • Built-in VFS service for the initrd

    • ELF loader

    • Service-lookup protocol service

  • Userland UART driver

  • Userland UEFI framebuffer driver

  • Userland kernel log output service

  • Userland unit test runner

  • Build configuration system (bonnibel)

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