Despite these challenges, microkernel-based systems have been successfully used for various applications and domains. For instance, MINIX is a microkernel-based system that is designed for teaching and research purposes. It is known for its reliability, portability, and simplicity, and it inspired the development of Linux. Another example is QNX, a microkernel-based system that is widely used for embedded and real-time systems, such as automotive, industrial, and medical devices. It offers high performance, scalability, and security, and it supports POSIX standards. A third example is L4, a family of microkernel-based systems that are optimized for high-performance IPC and virtualization. L4 can run multiple operating systems on top of the microkernel, such as Linux, Windows, or Android, and it can also support trusted computing and security features.