We always had 5 1 hour periods at high school. You did each subject 4 times a week and most kids did 5 subjects - in the first few years the extra 5 hours were allocwted to PE, art and music but senior students could use them for study or add a sixth subject.

I have trouble imaging 7 classes a day but i know my parents had that although they had double periods for science labs etc. I quite like the 3 short 1 long a week as it reminds me of university - 2 lectures, 1 tutorial and a lab.