Teaching Operating Systems Using Code Review

Learning about operating systems often involves modifying a large and complex code base. Grading student projects can be difficult and time consuming, yet students often do not learn from their programming errors and struggle to understand core operating system concepts. We present GradeBoard, a code review system designed to simplify grading for instructors and enable students to understand and learn from their errors. GradeBoard provides an easy-to-use Web interface that allows instructors to annotate student code submissions with grading comments and scores, and students to discuss the comments and scores with instructors. GradeBoard presents student code changes with syntax highlighting and lets users collapse or expand code sections to provide a desired level of context, making it easier to read and understand student programming project submissions. Comments and scores are easily identifiable by visual cues, improving interaction between instructors and students. We have deployed and used GradeBoard in a large operating systems course involving Linux kernel programming projects. GradeBoard provided robust, easy-to-use functionality for reviewing Linux kernel code changes, improved the instructional staff grading experience, and over 90% of students surveyed indicated that GradeBoard improved their understanding of the kernel programming projects better than other alternatives.