Open-source alternatives to Kernel

Limine is a multiprotocol operating system bootloader that bridges low-level hardware initialization and system software across legacy BIOS and modern UEFI firmware environments. It executes directly on bare-metal hardware without an underlying operating system kernel or standard C library, parsing storage media and filesystems during the early boot sequence before OS drivers load. The software targets diverse processor architectures including x86, ARM, RISC-V, and LoongArch through discrete target binaries built from shared source code. It reads files directly from FAT and ISO9660 storage f

This project is an implementation of the Arduino framework for ESP32 microcontrollers, providing a core that enables firmware development using a familiar API. It functions as a microcontroller hardware abstraction layer and a firmware toolchain integration, bridging external development environments to the hardware for compilation and flashing. The system includes an embedded real-time operating system wrapper to manage multi-core execution and task scheduling, alongside a wireless communication suite for TCP/IP networking and Bluetooth Low Energy. It distinguishes itself by providing an obj

This project is a bare-metal operating system developed for ARM64 architecture. It serves as a low-level implementation of kernel engineering, focusing on the fundamental construction of an OS from the hardware level up. The system is distinguished by its comprehensive approach to ARM64 processor control, featuring a red-black tree task scheduler and a hierarchical page table system for virtual memory management. It implements a sophisticated privilege model that handles transitions between kernel and user modes, ensuring process isolation through address space splitting and exception level m

OpenRazer is an open source driver and daemon for controlling Razer peripheral lighting and hardware settings on GNU/Linux. It functions as a Linux input device manager and RGB peripheral controller, providing a background service that handles raw USB communication and state monitoring for compatible gaming mice and keyboards. The project provides a D-Bus hardware interface that exposes device control functions to third party applications via a system message bus. This communication layer allows scripts and external software to manage physical hardware components through a programmatic interf

Lua RTOS for ESP32 is a real-time operating system designed for ESP32 microcontrollers that integrates a lightweight Lua interpreter to manage hardware resources and application logic. It utilizes a micro-kernel architecture to provide preemptive task scheduling, ensuring deterministic timing and reliable concurrency for embedded operations on resource-constrained hardware. The system distinguishes itself by providing a unified hardware abstraction layer that maps high-level programming commands directly to peripheral registers. This allows developers to interact with sensors, actuators, and

This repository provides the Android device kernel and the corresponding Linux kernel source tree. It serves as the foundational codebase for managing the hardware architecture and power management of mobile devices. The project includes a comprehensive mobile hardware driver set designed to manage device-specific components, such as CPUs, GPUs, and cellular modems. The source code supports activities including Android kernel customization, custom ROM development, Linux kernel auditing, and mobile driver development.

embedded-notes is a collection of technical study guides and development notes focused on embedded Linux, Linux kernel internals, and C programming. It serves as a reference for embedded systems development and a preparation resource for technical interviews in the field. The project provides detailed documentation on writing device drivers, managing virtual memory, and understanding kernel internals. It also includes guides on IoT network protocols, such as MQTT and TCP/IP, and outlines the architectural details of chip architectures and hardware peripherals. The material covers a broad sur

TastyIgniter is a comprehensive restaurant management system and digital ordering engine. Built as a modular application framework, it provides the tools necessary to operate online food ordering, table reservation systems, and multi-vendor e-commerce platforms. The platform is designed to handle complex restaurant operations, including multi-location networking and multi-vendor marketplace management. It distinguishes itself through specialized restaurant automation, such as coordinating guest limits and time slots for bookings, managing ingredient and allergen catalogs, and implementing mul

Kernel is an educational hobby operating system and low-level systems programming project written in Rust. Designed for students and hobbyists, the project provides a minimalist environment to explore computer architecture, CPU design, and kernel development directly on hardware without relying on a standard library or underlying operating system. The implementation features a freestanding language runtime and a custom target specification that replaces standard library components for bare-metal execution. It includes a multiboot bootloader interface to parse early-boot hardware handoff stat

The Linux kernel is a monolithic operating system core that manages hardware resources, memory, and process scheduling across diverse computing architectures. It provides a standardized, POSIX-compliant environment for application execution while maintaining a modular driver framework that allows for the dynamic loading and removal of hardware interfaces. The project is distinguished by its high-performance concurrency toolkit, which utilizes lockless synchronization primitives and read-copy-update mechanisms to manage shared data access in multi-core environments. It incorporates a comprehen

GEF is a Python-based extension for GDB that serves as a framework for binary analysis, exploit development, and low-level debugging. It functions as a dynamic analysis extension designed to assist in reverse engineering workflows and malware analysis by enhancing the debugger's ability to inspect process state and memory. The project is distinguished by its specialized heap analysis tools, which allow for the inspection of glibc heap arenas, bins, and chunks to detect memory corruption. It also provides a dedicated toolkit for exploit development, including cyclic pattern generation for offs

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

FreeRTOS-Kernel is a real-time operating system kernel for microcontrollers. It provides a multitasking environment through a priority-based task scheduler, an embedded memory manager, and an inter-process communication framework to ensure time-critical tasks meet their deadlines. The kernel includes a software timer engine for executing functions at predefined intervals or after set delays. It supports a minimal model of concurrent tasks and lightweight co-routine execution for systems with limited memory resources. The project covers a broad surface of embedded resource management, includi

This repository contains the complete source code for the OpenBSD operating system and its base utilities. It is a Unix-like operating system focused on a secure, portable, and multi-user environment, featuring a C-based system kernel that manages hardware resources and provides essential services. The project provides a source-based system construction model to compile the core kernel and base utilities from raw files. It includes a cross-compilation toolchain for generating the tools and headers necessary to build binaries for target architectures different from the host machine. The codeb

This project is a comprehensive educational framework designed to guide learners through the complexities of systems engineering and low-level software development. It provides structured learning paths that integrate hardware simulation, source code analysis, and project-based exercises to help developers master the foundational concepts of computer architecture, operating systems, and firmware design. The curriculum distinguishes itself by emphasizing direct interaction with system internals, requiring learners to examine and modify existing open-source kernel and driver implementations. By

SerenityOS is a complete, self-hosted desktop operating system built from the kernel up. It features a monolithic kernel architecture that manages system services, hardware drivers, and networking within a single address space. The system provides a full computing environment, including a proprietary windowing system and a suite of native desktop applications, all while maintaining a POSIX-compliant interface for standard system programming. The project is distinguished by its integrated development workflow, which relies on a cross-compilation build pipeline to generate system images from ho

sysbench is a database and system benchmark tool used to measure the throughput and latency of database systems and hardware components. It functions as a multi-threaded workload generator and hardware performance profiler designed to determine how systems perform under heavy load. The project serves as a scriptable benchmark engine, allowing for the definition of custom performance scenarios through scripts. It simulates real-world traffic patterns by generating random data based on mathematical probability distributions, such as Zipfian, Gaussian, or Pareto. Capabilities cover database per

BabyBluetooth is a Bluetooth Low Energy library and wireless device communication API for iOS and macOS. It serves as a central manager for discovering nearby wireless devices, managing the lifecycle of active connections, and providing a programmatic interface to read and write characteristic values to control remote hardware behavior. The library includes a peripheral manager that allows a device to simulate a wireless peripheral by advertising services and characteristics for other hardware to discover and interact with. The framework covers device discovery through scanning and filtering

Mbed OS is a real-time operating system designed for connected internet-of-things devices and microcontroller hardware. It provides a fundamental framework that combines a real-time operating system with an embedded security framework, a hardware abstraction layer for controlling sensors and peripherals, and a device management platform for cloud-based orchestration. The system establishes security foundations to protect connected products from unauthorized access and vulnerabilities. It further enables remote monitoring and hardware orchestration by connecting embedded devices to cloud servi

Codebox is a browser-based integrated development environment used for writing and executing source code across cloud and desktop environments. It functions as a Node.js runtime environment, allowing JavaScript and Node.js code to run directly within a web browser. The project is a cross-platform IDE with native support for offline usage. It utilizes a modular plugin architecture that enables the addition of custom third-party functionality and extensions to the editor. The environment includes tools for codebase management, an integrated file system layer, and a command line interface for w

Kratos is a toolkit for building cloud-native microservices in Go. It provides a comprehensive suite of framework primitives, including a dedicated toolset for API-first development using Protobuf to generate server and client code for gRPC and HTTP. The project is distinguished by its pluggable service infrastructure, which allows for the swapping of configuration stores, service registries, and data encoding formats. It utilizes a composable middleware pipeline to inject cross-cutting concerns such as authentication, request validation, and circuit breaking into the service flow. The frame

EverShop is a TypeScript-first, modular e-commerce platform built with GraphQL and React. It provides a full-featured online store system for managing products, orders, customers, and site content through a React-based administrative interface, with a GraphQL API layer that serves both the admin panel and storefront. The platform is designed around a module-based extension architecture, where core functionality is split into independent modules that can be added, removed, or overridden without modifying the core codebase. Storefront appearance and behavior are controlled through a theme syste

proxy.py is a lightweight, dependency-free HTTP and reverse proxy framework built in Python that handles network traffic through asynchronous event loops and multi-core connection distribution. It acts as a customizable proxy server and embedded web server, allowing developers to inspect, route, and modify web traffic programmatically or via command-line execution wrappers. The platform provides in-flight TLS interception and traffic decryption using generated root certificates, alongside modular extension hooks that support custom dashboard interfaces, request handling plugins, and REST API

aimeos-core is a PHP e-commerce framework designed for building scalable online stores. It functions as a headless e-commerce engine for managing products, orders, and catalogs, and provides a modular storefront framework and an extensible administration interface. The system utilizes a modular extension architecture that allows for the injection of custom business logic and the addition of new features through plugins without altering the core source code. It employs a decoupled rendering model that separates the administration interface from the customer-facing storefront. The framework pr

This project provides educational resources and technical guides for microcontroller firmware development. It focuses on writing low-level C code that runs directly on hardware without an underlying operating system, covering the fundamentals of hardware registers, memory mapping, and system clocks. The guides detail the creation of hardware abstraction layers to wrap raw memory-mapped registers into structured interfaces and provide walkthroughs for integrating TCP/IP stacks and HTTP servers into bare-metal environments. It also outlines the implementation of embedded systems build pipelines

Cryptomator is a client-side cloud encryption tool and cross-platform vault manager. It provides a transparent encryption layer that encrypts files and folder structures locally before they are uploaded to a cloud storage provider. The software creates virtual encrypted drives that mount encrypted vaults, allowing users to interact with their data as if it were on a physical disk. It supports the management of multiple independent encrypted containers, each protected by a unique password. The project covers data privacy through directory structure obfuscation and filename encryption to hide

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