It is true that a lot of legacy COBOL apps are on mainframe. However, not all - I've personally been dealing peripherally with COBOL on UNIX/Linux via IBM or M

It is true that a lot of legacy COBOL apps are on mainframe. However, not all - I've personally been dealing peripherally with COBOL on UNIX/Linux via IBM or MicroFocus compilers for decades - and it even works on Windows :-O e.g. https://www.microfocus.com/en-us/products/net-express-server-express/overview https://www.microfocus.com/en-us/products/net-express-server... https://www.ibm.com/ca-en/marketplace/cobol-compiler-aix https://www.ibm.com/ca-en/marketplace/cobol-compiler-aix