Yes, indeed. I started as a bank programmer, working on an IBM mainframe. At night, nearly the whole machine was consumed by batch processing. If there was so

Yes, indeed. I started as a bank programmer, working on an IBM mainframe. At night, nearly the whole machine was consumed by batch processing. If there was some problem that required a late-night fix, it was worked out first on green-bar print of the program, using hex to determine what was in the registers. Then the code could be submitted via ICCF, but the wait for a compile could take literally hours. If you mis-typed something (say a forgotten period), the compile would fail and you would have to resubmit the job. Waiting hours again!