Sounds like we went to UM at the same exact time.
Old IBM computer punch cards. You had to register for classes like you were collecting Pokemon cards or something. If you decided to drop a class, you had to turn in the old punch card, and then each college or school would have to reprint new punch cards for the next day of registration. Literally, you could pick up the last spot in a class, decide you wanted a different class 5 minutes later, and nobody else could get into that class until the next day. Then, once you had your 5 or 6 classes, you would turn in all your punch cards to "register".
We had separate student IDs (non-magnetic) and cafeteria cards (magnetic). Originally, you could only use your cafeteria card in the actual full-meal cafeterias, not the Ibis or the fake Burger King next to the pool.
Pretty sure we know each other...