Minix 3

Minix 3 is a modular, microkernel-based operating system designed to be highly reliable. It is a descendant of the original MINIX operating system created by Andrew S. Tanenbaum for educational purposes. However, unlike its predecessor, Minix 3 is specifically designed for use in embedded systems and other applications where high reliability is critical.

A key feature of Minix 3 is its use of a microkernel architecture. This means that only the essential operating system functions, such as process management and memory management, run in kernel mode. Other functions, such as file systems and device drivers, run as separate user-mode processes. This design isolates these components from the kernel, preventing errors in one component from crashing the entire system. If a driver or other user-mode service fails, it can be automatically restarted without affecting the core kernel or other processes.

Minix 3 emphasizes modularity and fault tolerance. The operating system is designed to be small and easily extensible, with a clear separation of concerns between different components. It incorporates mechanisms for automatically detecting and recovering from failures, such as driver crashes. This focus on reliability makes Minix 3 suitable for applications where downtime is unacceptable.

The system also features a process manager that monitors and restarts drivers, further contributing to its resilience. This allows the system to self-heal from many common software failures.

Minix 3 is available under a BSD license, making it free to use and modify. It has been used in a variety of applications, including embedded systems, security appliances, and as a research platform for operating system design.