Open-source alternatives to Embedded Notes

The Linux Kernel Module Programming Guide is an educational resource that teaches how to write, compile, and manage loadable kernel modules for modern Linux kernels. It covers the complete lifecycle of kernel modules, from building and loading to unloading and debugging, with a focus on extending kernel functionality without recompiling the entire kernel. The guide provides comprehensive coverage of core kernel programming concepts including dynamic module loading, file-operation registration, interrupt handling, kernel-user data copying, concurrency control, and deferred task scheduling. It

CppGuide is a curated collection of educational resources and practical guides focused on C++ server development, Linux kernel internals, concurrent programming, network protocols, and security exploitation. It provides structured learning paths for backend developers, covering everything from interview preparation to building high-performance network servers and understanding operating system fundamentals. The guide distinguishes itself by offering in-depth, hands-on tutorials that walk through real-world implementations, including building a Redis-like server from scratch, designing custom

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 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

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

This project provides a structured educational curriculum designed to teach Linux kernel internals and system architecture. It serves as a comprehensive training resource for developers, offering hands-on laboratory exercises that cover core operating system principles such as memory management, process scheduling, and interrupt handling. The curriculum distinguishes itself by mapping theoretical concepts directly to kernel source code, allowing learners to navigate and analyze system internals through practical implementation tasks. It facilitates the development of hardware device drivers a

TCP-IP-NetworkNote is a comprehensive technical reference and guide for implementing network communication using TCP and UDP sockets in C and C++. It provides a detailed manual for using the POSIX socket API and covers the implementation of network protocols, synchronous and asynchronous I/O patterns, and concurrent programming models. The project is distinguished by its focus on cross-platform networking, offering a detailed comparison of socket implementation details and adaptation utilities between Linux and Windows Winsock environments. It specifically addresses the differences in header

This project provides a development framework for writing loadable Linux kernel modules using the Rust programming language. It establishes a methodology for safe systems programming by enforcing memory and thread safety within the restricted execution environment of the kernel, allowing developers to extend operating system functionality while preventing common memory corruption errors. The framework distinguishes itself through automated generation of type-safe foreign function interfaces, which bridge high-level code with low-level kernel headers and system structures. It maps high-level s

This project is a technical reference and educational guide focused on the internal architecture of the Linux kernel. It serves as a low-level systems programming resource and documentation for operating system internals, detailing the implementation of core mechanisms within the kernel source code. The materials provide a detailed study of the Linux kernel, tracing behavior through actual C source and assembly. It specifically covers the progression from the bootloader and decompression to the final kernel entry point, alongside the management of hardware interrupts and symmetric multiproces

NuttX is a POSIX-compliant real-time operating system designed for microcontrollers ranging from 8-bit to 64-bit architectures. It provides a deterministic execution environment with a real-time task scheduler and a POSIX embedded kernel to ensure portable code execution across diverse hardware targets. The project distinguishes itself through a comprehensive hardware abstraction layer that provides standardized drivers for I2C, SPI, CAN, and USB across various semiconductor chipsets. It also features an embedded networking stack supporting TCP, UDP, IPv4, and IPv6, alongside industrial proto

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

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

Hammerspoon is a programmable automation engine for macOS that enables deep system-level control through a Lua scripting environment. By bridging high-level scripts with native Objective-C APIs, it allows users to interact with the operating system's accessibility tree, intercept hardware input streams, and manage the lifecycle of running applications. The project distinguishes itself through an event-driven architecture that registers asynchronous hooks for system notifications and hardware events. This allows for real-time automation, such as remapping keyboard and mouse inputs, managing wi

InterviewGuide is a comprehensive technical interview preparation platform that covers the full spectrum of software engineering recruitment, from foundational computer science concepts through to offer negotiation. It provides structured learning paths across algorithms, operating systems, databases, networking, and programming languages, with a particular emphasis on C++ and Go. The platform aggregates real interview experiences and company-specific questions from major tech employers, offering candidates a searchable database of past written exam problems and detailed accounts of actual int

This project is a C++ TCP server framework and educational socket programming guide. It provides a high-performance network library focused on event-driven architecture, implementing a reactor pattern to handle thousands of simultaneous client connections. The framework is distinguished by its multi-threaded event loop, which utilizes a main-sub reactor coordination model to distribute network events across a worker thread pool. It includes an abstraction layer for non-blocking socket I/O and event multiplexing via the epoll system call, decoupling network transport from application business

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 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.

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 an open source Linux GPU kernel driver implemented as a loadable kernel module. It functions as a GPU firmware loader, providing the low-level driver services necessary to enable direct communication between the operating system and graphics processing units. The driver utilizes a dual-module architecture that separates GPL-licensed kernel code from proprietary firmware blobs. This system extracts and links signed binary firmware images into the kernel modules at driver load time. The project provides driver support for Turing-architecture GPUs and all subsequent newer hardwa

klib is a comprehensive C standard library extension and data structure toolkit. It provides a set of fundamental tools for memory management, data organization, and general-purpose utility functions for standalone C applications. The project features specialized capabilities for bioinformatics sequence analysis, including the parsing of FASTA, FASTQ, and Newick formats and the implementation of Smith-Waterman sequence alignment and Hidden Markov Models. It also includes a mathematical computation library for numerical routines and expression evaluation, as well as a lightweight HTTP and FTP

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

nix is a Unix system API library and Rust system programming interface that provides type-safe bindings for invoking low-level system calls. It serves as a low-level operating system wrapper and POSIX compatibility layer, allowing for kernel interactions and administrative tasks through safe wrappers around platform-specific APIs. The project provides a kernel device interface for controlling hardware devices, managing kernel modules, and configuring terminal interfaces. It differentiates itself by offering type-safe wrappers for memory mapping and zero-copy input-output operations to reduce

This project is a technical study and analysis guide focused on the internal architecture of Node.js. It provides an in-depth examination of the runtime, focusing on how the engine manages memory handles, executes asynchronous operations, and implements core module logic. The guide specifically analyzes the integration of native C++ classes and functions into JavaScript and documents the behavior of the libuv event loop. It includes detailed references for optimizing performance by identifying V8 compiler bailouts and profiling execution to improve resource efficiency. The material covers a

c3c is the compiler for the C3 programming language, transforming source code into executable binaries, static libraries, or dynamic libraries using an LLVM backend. It implements a system based on result-based error handling, scoped memory pooling, and a semantic macro system. The compiler provides first-class support for hardware-backed SIMD vectors that map directly to processor instructions and enables runtime polymorphism through interface-based dynamic dispatch. The project covers a broad set of low-level capabilities, including manual and pooled memory management, inline assembly inte

This project is a Windows Precision Touchpad driver and Apple Trackpad HID driver. It functions as an input device gesture driver that converts raw touch data from Apple trackpads and MacBooks into native multi-touch gestures and precise pointer movement. The driver implements the precision touchpad protocol to enable native Windows gesture and pointer controls for Apple hardware. This allows the operating system to recognize Apple trackpads as precision touchpads, replacing basic mouse functionality with native multi-finger swipes and precise scrolling. The implementation covers kernel-mode

This project is a comprehensive technical documentation repository focused on Linux system administration, network security, and privacy-oriented computing. It provides a curated knowledge base of instructional guides and configuration tutorials designed to assist users in managing low-level system environments, kernel compilation, and bootloader setup. The repository distinguishes itself by emphasizing privacy engineering and infrastructure hardening. It offers detailed procedures for anonymizing network traffic, securing credentials, and isolating applications within a computing environment

POCO is a comprehensive C++ application framework that provides a cross-platform set of libraries for building network-centric applications. It offers a unified abstraction layer that wraps platform-specific APIs, enabling the same code to run across desktop, server, mobile, IoT, and embedded systems. The framework is organized into modular libraries that can be compiled and linked selectively, allowing developers to include only the components their application needs. The framework distinguishes itself through its broad coverage of application infrastructure needs, including threading and sy