6.002x is the first electronic circuits course to be taught online to tens of thousands of students. The goal of the 6.002x experiment was to explore ways to use computer assisted instruction to surpass the quality of traditional residential teaching. By providing superior on-line content delivery and assessment, we hope to both be able to educate people without access to education, and to improve residential education by allowing professors to focus on higher value tasks. We improved on the classroom experience in several ways. Students can actively monitor their current levels of mastery and to self-pace in response. They can identify and break through misconceptions before moving on to more advanced material. The massive scale of the classroom has participants on-line 24/7, allowing students to ask questions and receive peer answers in almost real-time. The platform allows for substantial data collection on testing, allowing us to incrementally and scientifically improve courses. Finally, the amount of effort that can be invested into a course is much greater when it can be amortized across tens of thousands. In order to achieve this, we had to overcome a number of challenges: finding mechanisms to allow automated grading, overcoming the lack of in-person interactions, and overcoming the lack of student access to laboratory equipment. The course was shown successful in both residential and mass-scale settings.

We have designed and built the Orrery, a special computer for high-speed high-precision orbital mechanics computations. On the problems the Orrery was designed to solve, it achieves approximately 10 Mflops in about 1 ft3 of space while consuming 150 W of power. The specialized parallel architecture of the Orrery, which is well matched to orbital mechanics problems, is the key to obtaining such high performance. In this paper we discuss the design, construction, and programming of the Orrery.