I trained on the IBM 370/135 and mostly in the USA then they ran Cobol for the US insurance industry. Those platters of disks kids today would not believe. But I ended up running mostly machine code on HP laser-directed photoplotters running code akin to Fortran but really like a Unix C (n-1). Those were running code copied to tape, then the tape got loaded on the photoplotters. So figure 5-6 hours of sequential data output on to film in a darkroom.
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