Title
Managarm: A Fully Asynchronous Operating System

Authors
Alexander van der Grinten, Kacper Słomiński, Geert Custers

Affiliation
The Managarm Project

Abstract
In this paper, we give an overview of the system architecture of Managarm, a free and open source operating system that is based on a microkernel. The goal of Managarm is to build a general-purpose OS on top of unprivileged drivers and servers that run in user space, while still providing extensive source-level compatibility with existing POSIX and Linux applications. To minimize context switches even when driving modern hardware that supports high degrees of concurrency, Managarm exclusively relies an asynchronous IPC mechanism that enables the submission of an arbitrary number of independent IPC requests before performing a context switch. Additionally, since existing POSIX and Linux applications are not always designed around asynchronicity, we provide a user level emulation of POSIX and Linux APIs. Our emulation is sufficient to run various Linux application, including modern desktop environments.