My first major program was a simulation of a complex heat pump written in Fortran IV on a PDP-11. I still remember that the printout was roughly 4-5 metres long, and that compiling it meant I could go for a coffee break 
[cue computer nostalgia]
Ah, kids today. Back when I was learning COBOL (business school) and FORTRAN (engineering school)
*, our FORTRAN teacher told us about the good old days when
he was a student. (People in the class were complaining about how loooong it took to get a program printout from the university computer center.)
"When I was a student, we coded on punch cards, 80-column cards. First you had to write your program, in longhand on 80-column coding sheets. You'd hand your stack of sheets into the first window at the computer center. After punching your source deck, they'd hand it to you, then you'd hand it in to the next window where they ran it through the compiler. If you had any compile errors, they handed you back the error deck so you could go and fix your mistakes. Otherwise if you were lucky you'd hand your object deck to the third window, where they'd run it. If you had any run-time errors ... ".
* Both on mainframes (Univac and Honeywell DPS-8) using time-share terminals (green-screen 80x25 or DEC typewriter terminals). High tech.