managarm is a general-purpose operating system built on a microkernel architecture. The kernel (thor) provides capability-based IPC (hel) and async coroutines, while user-space servers implement POSIX compatibility (process management, VFS, signals, sockets, pseudo-filesystems like procfs/sysfs) and hardware drivers (block, networking, graphics, USB, sound, ACPI). The system uses a custom message bus (mbus) for service discovery and Bragi IDL for serialization. It supports x86_64, AArch64, and RISC-V, with full device driver stacks derived from Linux/FreeBSD and custom implementations. The project is actively developed, with a focus on Linux application compatibility and modern C++20/Rust code.
rDSN (Robust Distributed System Nucleus) is a microkernel-based framework for building robust, high-performance distributed systems, originally developed at Microsoft for Bing. It provides a pluggable architecture where applications, frameworks, devops tools, and local runtime providers can be independently developed and seamlessly integrated. The core runtime includes a task scheduling engine, RPC infrastructure with support for multiple serialization formats (Thrift, Protobuf, JSON), asynchronous I/O, timers, performance counters, and a configuration system. Key entry points are `dsn_run` and `dsn_run_config` in `src/core/src/main.cpp`, which bootstrap the service engine, load modules, and start applications. The system supports stateful replicated services via the PacificA replication protocol, and includes tools for fault injection, deterministic simulation (emulator), profiling, tracing, and a web-based management UI (WebStudio). External dependencies include Boost.Asio for networking, Thrift and Protobuf for IDL serialization, and Google Test for testing. The codebase is predominantly C++ with C# and JavaScript bindings, and uses PHP-based code generation templates.
This repository implements Composite, a component-based research operating system where kernel policies (scheduling, memory management, synchronization) are implemented as user-level components. It runs on x86-32, x86-64, and ARMv7a architectures, primarily under QEMU. The system provides a minimal kernel with capability-based security, synchronous invocation (sinv) for inter-component communication, and shared-memory channels. It includes a full musl libc port for POSIX compatibility, a DPDK-based network stack, an lwIP adapter for TCP/IP, and a simple VMM with virtio-net and device emulation. The architecture is closer to a microkernel than a traditional monolithic kernel, with components loaded and composed via a Rust-based composer tool that reads TOML specifications. A large suite of microbenchmarks measures IPC, scheduling, and synchronization latency. The codebase is pre-alpha quality, with many FIXMEs and incomplete features, but demonstrates strong craftsmanship in its abstraction layers (assembly stubs, channel library, scheduler framework, perfdata utility).