Ah, a kindred soul. I, too, learned FORTRAN II on an IBM 1620 in college. After graduation I programmed FORTRAN IV on an IBM DCS (direct coupled system) which was a 7094 running as a slave to a 7044 which handled the card readers, punches, line printers and tape drives. All mass storage was on 800 bpi magnetic tapes. No, friends, disc drives were no where to be found.
The 7094 had 36k words (36 bits/word) and the code was in BCD. Not much power for a several million dollar set of cabinets that filled a room and ate A/C.