My dad said guys he worked with back in the 1960's would have stacks of library routines on punch cards that they would assemble their programs from with a mini

My dad said guys he worked with back in the 1960's would have stacks of library routines on punch cards that they would assemble their programs from with a minimal amount of purpose written code. Once it was finished they run the stack through a duplicator that would also renumber the cards. Then they'd take the original deck and stick the library functions back in their library.