Why would anyone write a COBOL program? Java is much quicker. I write all my jobs in Java now using PL/SQL packages for the business logic.
The problems I fixed were due to a different compiler, which is one of the drawbacks of COBOL. I had another COBOL program that had a Linkage Section for a call to another COBOL program. That was a nightmare.
One reason would be that Java hadn't been invented yet.
Hey, I started on COBOL 86 where you could write your own memory management by bringing parts of the program in and out of memory.
As for deep calls, try PeopleSoft COBOL. There are sometimes 5 or 6 deep nested calls with combined COPY and CALLs and Linkage Sections the size of Baltimore (also made up of sometimes dozens of copybooks).
I am one of the guys they are talking about — wrote COBOL for over 20 years.
This was very helpful for me as I am independent and did’t even think of featuring my old COBOL (and JCL, TSO, SPUFI and DB2) skills.
I am making up a CV that emphasizes those right now thanks to this article!
Large old system with very high volume of data.
Most remediated.. Lots of mainframes still around.