My college, in 1980, was running a Honeywell Level 2 GCOS mainframe. It had 208k of memory, and could run up to four concurrent tasks. The workstation I'm writing this post on has about 82,000 times the memory as that old beast, which physically approximated a large fridge laying on its side. The removable disk drives were sized like washing machines, had five 14-inch platters, and held 80k.
I took some Cobol courses, using keypunch machines and Hollerith punch cards. When assignments were due, you'd often see students lined up at the card reader, waiting to read in their programs. The first six columns of a punch card for Cobol programs was reserved for an optional sequence number, equivalent to a Line Number today. Nobody filled those in - not even our instructors. If you had to re-order your program, you really wanted to avoid having to re-type cards with new sequence numbers.
However, at the end of the last semester, minutes before the final assignment was due, my fellow student Peggy came running in to the data center with her purse and coat in one hand, and a six-inch deck of Cobol cards in the other, tripped in her haste to the card reader queue, and scattered 2000+ cards across the data center floor. And on the final day of the final semester, we learned why its sometimes good to put sequence numbers on your punch cards.
And btw, nearing the end of each semester, it ALWAYS took 24 hours to get a compile back.