Before you all go eeeewwww yuck who still uses COBOL, the answer is
lots of us. My immediate goal is to try to find out if there are many
Interbase / Firebird users who still use COBOL like we do.

As part of a project to integrate our legacy apps with the new stuff,
which uses Firebird, I am developing a simulated ISAM file handler for
Firebird. This will allow us to access the key Firebird tables with
little or no code changes to the existing COBOL programs. There are
going to be rather obvious performance issues with this approach but
that is a trade off that we are willing to make for the convenience of
not having the do a mass conversion of several thousand programs. It
also relieves us of the necessity of having to get all of our COBOL
programmers up to speed on SQL and transaction management and all of
the other gotchas of relational database development.

If there was sufficient interest we might consider making the file
handler generic enough to turn it into a commercial product.
Unfortunately we can't make it open source because we had to sign a
non-disclosure with the COBOL compiler folks before they would give us
the docs for their external file handler interface.