OS/161 is a simplified operating system we use for teaching the undergraduate operating systems class. It includes a standalone kernel and a simple userland, all written in C. It runs on a machine simulator, System/161, that offers simplified but still realistic hardware devices. (Neither OS/161 nor System/161 is in any way affiliated with IBM.)
If you want to get more information, please link to http://www.eecs.harvard.edu/~syrah/os161/.
And the course ECE344 online site is http://www.eecg.toronto.edu/~lie/Courses/ECE344/.
In the future this catagory OperatingSystemCourse will collect all myself studying of it. Please pay attention.