WinFsp is a Windows File System Proxy that provides a FUSE (Filesystem in Userspace) compatible API for Windows. It allows developers to create custom file systems in user space using C, C++, .NET, or any language that can call a C library. The repository contains a kernel-mode Windows driver (`src/sys/`) that handles IRP dispatch and communicates with a user-mode DLL (`src/dll/`) via a transaction protocol. It includes a comprehensive FUSE v2 and v3 compatibility layer, a native WinFsp API, a service launcher for running file systems as Windows services, a network provider for automatic mounting, and an extensive test suite. The architecture is a hybrid kernel/user-mode system, deeply integrated with Windows NTFS semantics. While primarily an application framework, it also contains performance benchmarking data and analysis notebooks in its documentation. The codebase is actively maintained, demonstrates high craftsmanship in a difficult domain, and contains several reusable components such as a fault injection framework, POSIX-to-Windows security mapping, and a directory buffer abstraction.
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.