Open-source alternatives to MS DOS

This project is a 6502 assembly language implementation of a platformer featuring running, jumping, and swordfighting, developed for the Apple II computer between 1985 and 1989. It serves as a piece of legacy retro gaming software designed to run on 8-bit hardware from the early computing era. The repository provides the assembly source code for the purpose of historical technical analysis and research. It allows for the study of original game source to perform technical analysis and historical research into early video games. The project covers domains including 6502 assembly programming, A

This project is a monolithic operating system kernel designed to serve as the foundational software layer for diverse computing architectures and embedded platforms. It manages core system services, including processor scheduling, memory allocation, and hardware resource distribution, to facilitate communication between user applications and physical hardware. The kernel utilizes a hardware abstraction layer and platform-specific device trees to ensure consistent operation across a wide variety of processors and specialized computing devices. It supports dynamic functionality through loadable

This project is a version-controlled Git archive and software archaeology dataset containing the continuous evolution of Unix source code from 1970 to the present. It serves as a chronological record of system history, synthesizing a versioned code timeline from disparate historical snapshots. The archive enables longitudinal software analysis by reconstructing a sequence of commits and merges from fragmented releases. This allows for the tracking of system evolution and the attribution of specific lines of code to original authors through synthesized version control metadata. The dataset co

Apollo-11 is a digitized archive of the original assembly language source code used in the Apollo Guidance Computer. It serves as a historic spacecraft software repository, preserving the flight-critical code developed for guidance, navigation, and control during the first moon landing. The repository provides access to the original source code used for the command and lunar modules. This collection enables the study of historical software engineering and lunar landing systems, focusing on the logic and hardware constraints of early aerospace engineering.

This project is an educational resource and technical reference for building operating systems from scratch. It provides a comprehensive guide to mastering x86 architecture and implementing core kernel components by writing code that executes directly on hardware without the support of standard libraries or operating system abstractions. The materials focus on low-level systems engineering, teaching users how to interpret technical datasheets to manage hardware resources. It covers the fundamental mechanics of bare-metal programming, including the use of assembly language to define execution

This project is a specialized collection of study guides, curriculum references, and implementation libraries designed for computer science academic certifications. It serves as a comprehensive study guide and preparation kit for the Chinese postgraduate computer science entrance examination, providing a curated reference for the core curriculum. The repository distinguishes itself by combining theoretical study materials with a practical data structure implementation library. This includes standard C code templates for fundamental structures such as linked lists, stacks, queues, and binary t

This repository contains the complete source code for a Unix-like operating system, including the monolithic kernel and base system utilities. It provides a BSD-derived system core and a full build toolchain required to compile a functional operating system for servers, desktops, or embedded devices. The system features a Linux binary compatibility layer that enables the execution and emulation of Linux binaries on a non-Linux platform. It also includes a modular kernel configuration process to tailor hardware support and system features during compilation. The project covers broad system ca

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

This project is a collection of minimal operating systems, bootloaders, and hardware drivers used to demonstrate low-level x86 system programming and hardware interfacing. It serves as a kernel development toolkit and a system programming lab designed for testing architecture concepts and hardware behavior within a system emulator. The repository provides reference implementations for creating bootable disk images and loading kernel stages. It includes guides for implementing protected mode transitions, memory paging, interrupt descriptor tables, and symmetric multiprocessing on x86 hardware.

30dayMakeOS is an educational hobby operating system project designed for the x86 architecture. It implements a monolithic kernel and a custom bootloader that transitions the CPU from real mode to 32-bit protected mode to enable flat memory addressing. The project focuses on low-level system development, featuring a custom graphics driver for direct pixel-buffer rendering and window management without an existing operating system. It includes an x86 bootloader that loads the kernel from disk into memory. The system covers core kernel capabilities including round-robin task scheduling for pro

This repository is a collection of solved algorithmic problems and data structure exercises designed for technical interview preparation. It serves as a polyglot reference implementation, providing a set of solved exercises based on a standard textbook to help candidates master the logic and complexity analysis required for coding tests. The project implements the same algorithmic logic across multiple programming languages to demonstrate platform-independent problem solving. This polyglot approach allows for the comparison of implementations across different tech stacks to highlight recurrin

iNAV is flight control firmware designed to manage the stability, movement, and flight dynamics of multirotors, fixed-wing aircraft, and rovers. It serves as an autonomous flight controller and GPS navigation software capable of executing waypoint missions and maintaining position and altitude hold. The system integrates GPS and compass data to enable autonomous navigation and automatic return to home sequences during signal loss or sensor failure. It includes an on-screen display generator to render real-time vehicle status and warnings directly onto a pilot video feed, alongside a flight te

Betaflight is open-source flight controller firmware designed to stabilize aircraft and manage sensor data through PID loops and motor control. It serves as a multirotor flight stack that integrates low-level drivers and control algorithms to manage electronic speed controllers, radio receivers, and telemetry hardware. The system focuses on real-time flight stabilization and telemetry routing. It includes a PID stabilization system to calculate motor outputs for aircraft stability and a flight telemetry manager to route real-time information to ground stations and on-screen displays. The fir

xv6 is a Unix-like educational operating system designed for teaching kernel concepts. It is implemented as an instructional kernel for x86 and RISC-V architectures, featuring a virtual memory manager and support for symmetric multiprocessing. The system is designed to demonstrate core OS principles through a simplified re-implementation of Unix Version 6. It provides a controlled environment for studying system calls, trap handling, and process lifecycles. Its capability surface covers process management, including scheduling and context switching, and memory management via page tables for

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 project is a Linux kernel designed for Windows Linux integration, providing the underlying operating system kernel required to execute binary files and applications within the Windows Subsystem for Linux. It utilizes hypervisor-based virtualization to run a full kernel within a lightweight utility virtual machine managed by a Windows host. The repository enables the customization and compilation of the kernel from source. This allows for the modification of system behavior, the addition of specific drivers, and the tailoring of hardware compatibility for virtualized environments. The sy

miniaudio is a single-file C audio library used for audio playback, capture, and hardware interfacing across multiple operating systems. It functions as an audio hardware abstraction layer, an audio processing engine, an audio synthesis engine, and a codec and resampler. The project implements a node-graph based system for routing digital audio signals, mixing, and 3D spatialization. It also includes a programmatic generator for noise patterns and basic waveforms used for sound creation and signal testing. The library covers digital signal processing, including audio format conversion and sa

This is a collection of academic programming projects that accompany an operating systems textbook, designed to teach core OS concepts through hands-on implementation. The projects span the major subsystems of an operating system, including process scheduling, memory management, file systems, and concurrency, with students building components from scratch in a simulated environment. The projects are structured to cover the full range of OS internals, from low-level kernel development to user-space system programming. Students implement lottery-based CPU schedulers, dynamic heap memory allocat

This project is an OpenWrt firmware builder and specialized Linux router distribution designed to repurpose Amlogic S9xxx series hardware into functional routers. It provides a hardware adaptation layer consisting of kernel modifications and drivers that enable the operating system to run on Amlogic ARM SoC devices. The project features an automated firmware pipeline for scheduling, building, and distributing custom images. It includes a device recovery toolkit for bootstrapping, flashing, and restoring factory images, and supports the conversion of devices previously running different mobile

This project is a comprehensive research platform designed for the end-to-end lifecycle of robotic learning. It provides a modular framework for training neural network policies—specifically through imitation and reinforcement learning—and deploying them onto physical robotic hardware. By offering a unified interface for hardware abstraction, the platform decouples high-level control logic from the specific sensors and actuators of diverse robotic systems. The framework distinguishes itself through a standardized approach to data and policy management. It utilizes a consistent schema for reco

This project is a high-performance, lightweight C graphics library designed for creating interactive user interfaces on resource-constrained embedded hardware. It functions as a comprehensive framework that provides a widget toolkit, a rendering engine, and hardware-agnostic drivers to support the development of graphical displays on microcontrollers and embedded systems. The framework distinguishes itself through a flexible, object-oriented widget hierarchy and a declarative layout engine that supports responsive design patterns like flexbox and grid systems. It enables developers to synchro

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

This project is a multilingual educational framework that provides curated roadmaps and translated resources for mastering core computer science subjects. It serves as a Chinese translation of a structured guide designed to help students and engineers learn computer science fundamentals through a sequence of recommended books and courses. The framework focuses on technical content localization, converting English computer science roadmaps into Chinese to improve accessibility. It utilizes a manual translation workflow to ensure conceptual accuracy across its study guides and resource collecti

This project is a comprehensive technical interview preparation guide and computer science knowledge base. It serves as a structured study resource designed to help software engineers review core engineering concepts and prepare for professional coding assessments. The repository focuses on a wide array of theoretical and practical domains, including detailed references for mobile application architecture and operating system fundamentals. It provides curated materials on software architecture patterns and network protocol analysis to support professional development. The content covers foun

This project is a comprehensive technical interview preparation resource and computer science interview guide. It serves as an educational reference for developers to study core software engineering fundamentals and common coding patterns required for employment screenings. The repository provides detailed guides and references covering data structures and algorithms, networking and security, operating systems, and web development. It specifically focuses on the implementation and complexity analysis of sorting, searching, and graph algorithms. The material encompasses a wide breadth of comp

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

Xtreme-Firmware is a custom operating system for the Flipper Zero designed to expand hardware capabilities and remove software restrictions. It functions as a multi-protocol signal emulator for capturing and replaying RFID, NFC, Sub-GHz, and Infrared signals to test hardware security. The project features a specialized USB HID attack framework for sending keystroke payloads and spoofing device identifiers over USB and Bluetooth. It also includes a WiFi penetration testing suite for scanning, sniffing, and sending deauthentication frames using a wireless development board. Broad capabilities