I took 6.001 in Spring '87. I loved it, aside from the slow computers in the lab. I pulled an all-nighter on a Saturday for a problem set not due until Thursday so as to avoid the crowds.<p>After the class was over I didn't use Scheme for another 10 years, but did everything in C. Scheme was just too slow in 1987. Both the language implementations and the hardware have come a long way. I use Scheme all the time now, and there are numerous popular languages, notably PHP and Ruby, that are slower than Scheme today.