How did the 1957 Cadillac Eldorado Brougham Digital Clock function at a time when computers were so large?

My knowledge of computer specs is limited so I may be missing something entirely, but what I do know is that digital processing was extremely intensive at the time, requiring large cabinets of "computers" so I'm wondering how the '57 Cadillac Eldorado Brougham's digital clock functioned.|||i doubt it was digital, but cars of the 50s were ahead of their time. they had a push shifter!|||Wasn't digital, was what they called a drum clock, never had one apart but probably had small round drums with hrs/mins on them. Long time ago year I graduated from HS and started messing with cars.