Mainframe, MVS and zOS Discussion

Hi,

Whenever I talk to colleagues from Java or cloud side, they ask why COBOL is still used. They feel it is outdated. I usually explain about reliability and banking systems, but not sure if it always convinces them.

How do you all handle such discussions? What is your one-liner to explain COBOL’s importance in 2025?

Many computer languages tend to have a purpose designed into them. FORTRAN is good at expressing mathematical ideas, BASIC is a beginners language (although it does, depending on the version, teach some bad habits), C is best for systems engineering, and so on.

COBOL is a language that is good at expressing business ideas. While it is verbose and wordy, if written well, it can be understood relatively easily by non-programmers familiar with the subject matter such as systems analysts and testers. If I needed to do some data processing, write a CICS transaction, or produce a report, I'd reach for the COBOL compiler as the best tool for the job.

Of course, the other reason it's still used is that there's rather a lot of it about that's not going to be rewritten any time soon!