I haven't taken an online course in CS for almost a decade. Shifting interests. Changes in the business structure of MOOC's...Basically since they stopped being

I haven't taken an online course in CS for almost a decade. Shifting interests. Changes in the business structure of MOOC's...Basically since they stopped being called "MOOC's" and became closed down. Helerstein's CS186 video lectures (Introduction to Database Systems, 2015) are probably the most informative CS-thing I have experienced online: https://archive.org/details/ucberkeley_webcast_dY48_UZhvhw https://archive.org/details/ucberkeley_webcast_dY48_UZhvhw But of course, it is not an online course. Just course lectures online. It's informative because the problems - IO, optimization, caching, concurrency, partition, etc. are all right there in ways that require engineering (i.e. theory alone won't get you to the required scale). YMMV. Good luck.