Open-source alternatives to Linux

Zephyr is a real-time operating system and cross-platform embedded framework designed for resource-constrained hardware architectures. It provides an embedded kernel that manages memory, power consumption, and hardware peripherals across multiple microcontroller architectures. The project utilizes a hardware abstraction layer to decouple high-level kernel services from physical hardware through standardized driver interfaces. It employs a device tree hardware description format and a hierarchical configuration system to optimize binaries and feature sets for specific hardware constraints. Th

TinyGo is a specialized compiler and development toolkit designed to bring the Go programming language to resource-constrained microcontrollers and WebAssembly environments. It provides a bare-metal runtime environment that enables high-level code execution without the need for a traditional operating system, utilizing an LLVM-based backend to generate efficient machine instructions. The project distinguishes itself through aggressive optimization techniques tailored for small hardware, including a static memory allocation strategy and whole-program dead code elimination that significantly re

Gobot is a robotics framework for the Go programming language designed for developing robotics, drones, and IoT applications. It provides a hardware abstraction layer with standardized drivers to interact with GPIO, I2C, SPI, and PWM interfaces across various single-board computers and microcontrollers. The framework functions as an IoT device orchestrator and BLE device manager, enabling the coordination of multiple sensors, actuators, and Bluetooth Low Energy peripherals. It includes specialized interfaces for drone control, allowing for the management of flight maneuvers and video streams

F Prime is a component-based framework designed for the development and deployment of embedded and spaceflight software. It provides a modular architecture that decouples software logic from communication interfaces, allowing developers to define system structures through a domain-specific modeling language. This model-based approach enables automated code generation, ensuring consistency across complex system topologies while maintaining strict interface contracts between software modules. The framework distinguishes itself through its integrated build system and ground data operations suite

SDL is a cross-platform development library that provides low-level access to audio, keyboard, mouse, joystick, and graphics hardware. It functions as a hardware abstraction layer, mapping diverse operating system interfaces into a unified set of functions to ensure consistent performance across different computing environments. The library serves as a foundation for multimedia and interactive application development by providing an integrated audio processing engine and a graphics rendering framework. It manages the complexities of hardware communication by normalizing raw input events and p

XNU is a hybrid operating system kernel that combines a microkernel architecture with a monolithic layer for system services. It provides a foundation for operating system development, incorporating standardized system-call interfaces, a modular device driver framework, and mandatory access control security. The architecture features a Mach-based microkernel and a BSD-based monolithic layer. It utilizes a message-passing inter-process communication bus for secure data exchange between isolated kernel components and user-space processes, alongside an object-oriented driver framework that decou

This project is a tutorial and framework for building a low-level, bare-metal operating system from scratch using the Rust language. It focuses on ARMv8 kernel development specifically for the Raspberry Pi 3, providing the resources necessary to implement a monolithic kernel that runs directly on hardware without an underlying operating system. The project distinguishes itself by providing a complete embedded cross-compilation suite within a containerized environment to ensure consistent builds. It includes a dedicated kernel deployer that uses a serial interface and chainloader to load and b

RT-Thread is an IoT real-time operating system and embedded device kernel. It provides a lightweight execution environment for microcontrollers, combining a real-time kernel with a hardware abstraction layer to manage multi-threaded task scheduling and hardware resource allocation. The project is built as a modular framework that utilizes a package-based ecosystem. This allows for the integration of reusable software libraries and high-level services through a loosely coupled architecture. The system covers real-time task scheduling, resource-constrained memory management, and embedded hardw

This project is a collection of technical documentation and guides designed as a computer architecture explainer. It provides educational resources on how processors and operating systems execute programs, focusing on the fetch-execute cycle and the fundamental relationship between hardware and the kernel. The documentation covers a wide range of low-level system operations, including detailed guides on the executable and linkable binary format, virtual memory management, and kernel-level operations. It specifically explores the mechanics of CPU scheduling, preemptive multitasking, and the us

Open-smartwatch-os is an operating system designed for resource-constrained wearable devices. It provides a development and testing environment that allows developers to build, validate, and debug firmware for smartwatches within a simulated desktop environment before deploying to physical hardware. The project distinguishes itself through a comprehensive suite of tools for hardware emulation and remote diagnostics. By utilizing a hardware abstraction layer and modular driver architecture, it decouples core system logic from specific physical components. This enables developers to run the ope

This project is an educational operating system kernel designed to demonstrate the fundamental architectural principles of memory paging and process management. It is implemented as a minimal kernel that serves as a practical reference for building a functioning system from the ground up. The implementation features a preemptive multitasking kernel that switches execution contexts between threads to share a single CPU. It includes an x86 virtual memory manager that uses paging to map virtual addresses to physical memory and isolate processes. The system covers low-level hardware interfacing

This repository provides the original source code and binaries for legacy disk operating systems. It serves as a historical software archive and a reference implementation for early personal computer operating systems. The project is designed for software archaeology, legacy operating system research, and the study of foundational kernel design. It allows for the technical analysis of historical software architecture and implementation. The codebase covers several core system areas, including monolithic kernel design, segmented memory addressing, and file allocation table indexing. It also i

OpenTabletDriver is a user-mode graphics tablet driver and USB HID input manager that translates raw USB input from digitizer hardware into system cursor and pen events. It serves as a hardware abstraction layer that normalizes input from various tablet brands into a consistent API, providing a cross-platform pen interface with pressure and tilt sensitivity. The project distinguishes itself through a plugin-based architecture and a profile-based configuration system, allowing for custom filters, interpolators, and persistent hardware setups. It includes specialized tools for hardware driver d

This project is an educational curriculum designed to teach the fundamentals of operating system development and low-level systems programming. It provides a structured sequence of lessons and code samples that guide users through building a functional kernel and bootloader from scratch, enabling a practical understanding of how software interacts directly with computer hardware. The repository distinguishes itself by focusing on the core mechanics of bare-metal execution. It covers the implementation of essential system components, including assembly-based bootloaders that transition process

This project is an educational resource for developing bare-metal operating systems and kernels from scratch on Raspberry Pi hardware. It provides a structured guide to systems programming using the Rust language, focusing on the implementation of core kernel components that execute directly on ARM-based hardware without the support of an underlying operating system or standard library. The tutorials emphasize a modular architecture that separates hardware-independent kernel logic from processor-specific and board-specific configurations. By utilizing a hardware abstraction layer and distinct

This project provides an open-source firmware platform and complete build environment for portable multi-tool hardware. It functions as an embedded operating system designed to manage radio, infrared, and physical interface components, enabling users to develop custom applications and system logic for specialized hardware devices. The firmware distinguishes itself through a modular architecture that organizes system functionality into isolated units, allowing for the development of custom user interfaces and logic. It includes a comprehensive collection of low-level drivers and applications s

This library provides a collection of low-level abstractions for interacting with hardware peripherals on Raspberry Pi devices using the Rust programming language. It serves as a type-safe interface for controlling physical pins and managing communication with external electronic components and sensors. The project distinguishes itself through its use of compile-time abstractions that map high-level function calls directly to hardware instructions, ensuring minimal runtime overhead. It provides consistent access to hardware by wrapping kernel-level device interfaces and memory-mapped register

This project is flight control autopilot software designed as a real-time operating system for managing the flight dynamics and navigation of autonomous multicopters, fixed-wing aircraft, and rovers. It serves as a multi-vehicle autopilot framework that supports various aircraft configurations, including vertical takeoff and landing platforms across industrial environments. The system includes a MAVLink communication stack for exchanging telemetry and command data between unmanned vehicles and ground control stations. It also provides a software-in-the-loop flight simulator to test autopilot

seL4 is a formally verified microkernel whose C implementation is backed by machine-checked mathematical proofs of correctness, confidentiality, integrity, and availability. It enforces strict isolation between processes through hardware-enforced address space separation and a capability-based access control system, where each process holds explicit rights only to the resources it has been granted. The kernel exposes hardware resources through a minimal API of system calls that manage threads, address spaces, and inter-process communication, with synchronous IPC supporting sender-identifying b

liquidctl is a command line interface and set of Python drivers used to monitor and control liquid cooling hardware. It functions as a liquid cooler controller, hardware telemetry tool, and RGB lighting controller, providing a unified way to manage temperatures, fan speeds, and pump rates for all-in-one and custom loop cooling systems. The project provides a Python hardware driver that enables programmatic control and telemetry collection without relying solely on the command line. It allows for the configuration of device lighting using standard RGB, HSV, and HSL formats. The system include

ESPHome is a framework for creating and managing custom firmware for microcontrollers, specifically targeting ESP32 and ESP8266 architectures. It replaces the need for writing complex embedded C++ code by allowing users to define hardware behavior, pin configurations, and automation logic through simple, declarative text files. The system automatically compiles these configurations into optimized binary images, providing a streamlined path from design to deployment. The project distinguishes itself through a modular, component-based architecture that emphasizes local-first control, ensuring t

This project is a comprehensive, curated directory of high-quality libraries, tools, and educational resources for C and C++ development. It serves as an ecosystem discovery index, helping developers navigate the vast landscape of third-party components, frameworks, and technical documentation available for the language. The collection is distinguished by its focus on high-performance systems programming and technical mastery. It provides deep coverage of specialized domains including SIMD-accelerated data processing, compile-time template metaprogramming, and asynchronous event-driven archit

Tasmota is a universal firmware platform for ESP8266 and ESP32 microcontrollers, designed to provide local control and management of smart home hardware. It functions as an event-driven automation controller that replaces proprietary factory firmware, allowing users to manage relays, sensors, and lighting systems without relying on external cloud services. The system is built on a modular driver architecture that enables dynamic hardware configuration and peripheral support through a web-based management interface. The platform distinguishes itself through a template-driven hardware mapping s

Bazzite is an immutable, atomic-image-based operating system designed for gaming performance and handheld hardware. It utilizes a read-only root filesystem and versioned images to provide atomic updates and instant system rollbacks, ensuring a stable core environment. The system is distinguished by its deep optimization for portable gaming devices, featuring dedicated handheld hardware management for CPU undervolting, fan control, and display refresh rate overclocking. It includes a specialized gaming mode that boots directly into a console-like interface with integrated input mapping and a t

Stats is a system performance monitor that tracks real-time hardware metrics and resource usage directly from the operating system menu bar. It functions as a hardware control interface, allowing users to adjust fan speeds and thermal settings to maintain optimal performance levels for computing hardware. The application distinguishes itself through kernel-level sensor polling, which retrieves telemetry by interfacing directly with low-level system drivers and power management APIs. It provides remote infrastructure oversight via a web-based telemetry dashboard, enabling users to view live pe

CS-Xmind-Note is a collection of structured mind maps and conceptual diagrams serving as a comprehensive knowledge base for computer science fundamentals. It functions as an academic reference and study guide, organizing core subjects into a visual mapping of interdependent technical concepts. The project utilizes an XMind-compatible schema to model complex domains through hierarchical nodes and relational concept mapping. This approach allows for the visual representation of technical layers, linking hardware specifications to software abstractions. The knowledge base covers several primary

systemd is a comprehensive system and service manager for Linux that orchestrates the entire operating system lifecycle. It functions as the primary init system, managing the transition from firmware to a fully initialized user space while providing a unified framework for service orchestration, hardware management, and resource control. The project distinguishes itself through its declarative, unit-based configuration model and dynamic dependency resolution, which allow for efficient, on-demand service activation and socket-based process management. It integrates deep system observability th