Keyronex is a hobby operating system. It runs to varying degrees on AArch64, m68k (Amiga and qemu virt), and amd64 PCs. It makes no pretences to be anything novel or exciting, and doesn't do anything likely to be interesting to anyone.

This is a refactoring branch which currently lacks features; the previous more featured branch is 23-jul, which features ports of such apps as the GNU Coreutils, BASH shell, Binutils, and GCC, as well as Xorg and some basic X11 apps such as Twm and Xeyes, and the Links text-mode web browser.

Architecture

Keyronex combines influences from the Unix tradition (particularly Mach, NetBSD, and Solaris) and the VMS tradition (particularly Mintia, Windows NT, and VMS itself). The virtual memory system has been given special attention.

Several logically distinct components run in kernel mode. These include:

• The kernel: providing multiprocessor scheduling, time management, interrupt management synchronisation, waiting, and remote-copy-update (RCU).
• The executive: higher-level services including virtual memory, the virtual filesystem switch, and the device manager.
• The drivers: run hardware and virtual devices and carry out I/O on behalf of the device manager.

The virtual memory manager is the most well-developed part of Keyronex, especially with respect to most other hobby OSes. Its design draws on the VM tradition of OpenVMS, Windows NT, and Mintia. In this branch it hardly does anything yet; its goal is to implement a VMM based on the Working Set Model of Denning.

The device manager is also quite well-developed in some respects. It is profoundly asynchronous, object-oriented, packet-based, and designed to minimise recursion. Devices are objects organised in a tree and operate by message-passing. Messages take the form of I/O packets (or IOPs), to which an explicit stack is attached, and these descend the device tree through an iterative, continuation-based mechanism that maintains state in the explicit stack of the IOP, minimising kernel stack use. Drivers themselves are written in Objective-C for ease of programming.

Requirements

To build Keyronex and all of the userspace you will need the following dependencies:

autopoint
gettext
git
gperf
help2man
libgmp-dev
libmpc-dev
libmpfr-dev
libtool
m4
meson (>= 0.57.0)
pkg-config
python3
python3-mako
python3-pip
texinfo
yacc
xbstrap
xorriso

These packages are gotten with apt install on Ubuntu, except for xbstrap, which is gotten with pip install xbstrap.

Third-party components

Several third-party components are used. These are some of them:

• Limine: The bootloader used for Keyronx on AArch64 and amd64.
• FreeBSD: queue.h and tree.h, generic type-safe list/queue and tree macros for C.
• nanoprintf: Minimal printf() implementation used for kprintf.
• NetBSD:
  • The Boldface font used on the Amiga port's PAC console.
  • Reference for Amiga port and source of chipset register definition headers cia.h, custom.h.
• Limine: A bootloader for PCs and UEFI-based AArch64 systems. Keyronex's default bootloader for the amd64 and aarch64 port. It also provides a terminal which is used as a library to provide Keyronex's FBConsole graphical console.
• mlibc: A portable C standard library. Provides the libc.
• nanoprintf: Printf implementation; provides kprintf and family.
• uACPI: The UltraOS ACPI Implementation from UltraOS. Used by the ACPI drivers.
• Various headers (mostly BSDs, some Linux): BSD-licenced headers for device registers definitions.

Licence

Code original to Keyronex is licenced under the Mozilla Public Licence v2.0 (MPLv2). Other components are under their own licences, all of which are MPL compatible; these are mostly under the BSD or similar licences. See the vendor and subprojects folders where the licences of the third-party components can be found.