Most operating systems instructors recognise the value of practical work in their courses. Laboratory-style practical work offers the student the opportunity to put their theoretical knowledge into practice. The incorporation of laboratory work into an operating systems course requires the use of practical aids that illustrate or reinforce the important concepts of operating systems theory. The design and implementation of such an aid, the SunOS MINIX Monitoring System, is described. This system is based on SunOS MINIX, a version of the MINIX instructional operating system that runs as a user process under SunOS. The aim of this project was to take advantage of the hosted nature of SunOS MINIX by constructing a communications interface that would permit it to be monitored and controlled by external (SunOS) processes. The monitoring system includes a set of tools allowing a user to inspect, monitor and control a running instance of the SunOS MINIX operating system.