A minimal instructional operating system framework for the 80x86 processor architecture by Stanford University (CS140). Details about the set of projects can be found here.
Extended functionality of the minimal thread system given by providing a non-busy waiting criteria to block threads, and implementing both a priority-based thread scheduler and an advanced multi-level feedback queue scheduler.
Allowed for loading and running userprograms that require interactivity or I/O processing by providing a system calls API and parameter passing mechanism, managing memory, scheduling and related exceptions in the process.