Hobbyist operating systems

MenuetOS is an operating system with a monolithic preemptive, real-time kernel written in FASM assembly language. The system also includes video drivers. It runs on 64-bit and 32-bit x86 architecture computers. Its author is Ville M. Turjanmaa. It has a graphical desktop, games, and networking abilities (TCP/IP stack). One distinctive feature is that it fits on one floppy disk.

KolibriOS is an open-source operating system for x86 computers, written completely in FASM assembly language. It has been developed since 2004, forked from MenuetOS, and supports i586 CPUs or newer. KolibriOS is small sized and fits on a single 3.5" floppy disk; despite this, it features a full graphical user interface, preemptive multitasking, networking capabilities, and many pieces of bundled software.

TempleOS (formerly J Operating System, LoseThos, and SparrowOS) is a biblical-themed lightweight operating system (OS) designed to be the Third Temple from the Hebrew Bible. It was created by American computer programmer Terry A. Davis, who developed it alone over the course of a decade after a series of manic episodes that he later described as a revelation from God. TempleOS could be considered as an example of coding as an art form, with the nature of his psychological instability and its influence over the project lending to comparisons to similar outsider art (see also Creativity and ment

operating system

operating system

SerenityOS is a free and open source desktop operating system. It features a preemptive kernel, currently supports x86-64, ARM, and RISC-V based computers, and hosts multiple complex applications including its own web browser and integrated development environment (IDE).

Redox is a Unix-like operating system based on a microkernel design. It is community-developed, released as free and open-source software and distributed under an MIT License. Written in the programming language Rust, Redox aims to be a general-purpose operating system that is safe and reliable. It is currently in a pre-stable status.

HelenOS is an operating system based on a multiserver microkernel design. The source code of HelenOS is written in C and published under the BSD-3-Clause license.

orthogonally persistent managed-code general purpose operating system

SYmbiosis Multitasking Based Operating System (SymbOS) is a multitasking operating system for Zilog Z80-based 8-bit computer systems.

Fiwix is an operating system kernel based on the UNIX architecture and fully focused on being POSIX compatible. It is designed and developed mainly as a hobbyist operating system, but it also serves for educational purposes. It runs on the i386 hardware platform and is compatible with a good base of existing GNU applications. It follows the UNIX System V application binary interface and is also mostly Linux 2.0 i386 system call ABI compatible.