I took 213 at CMU. Can't recommend it highly enough. A lot of other intro systems courses are based off that. It is a prerequisite for most classes moving forward at CMU. The textbook is also available online as a pdf (Google it). First 2 or 3 labs deal with bitwise, assembly (buf overflow attacks - bomb lab), then cache lab (matrix multiply performance), then signals, then implementing malloc, and finally using pthread API / threads to create a proxy server.