Acknowledgments

A book that bridges introductory COBOL instruction and enterprise-grade practice draws on the knowledge, generosity, and experience of a community far larger than its authorship. We owe deep thanks to the many individuals and organizations whose contributions made this book possible.

The COBOL Community

Our foremost thanks go to the global COBOL community -- the programmers, systems analysts, architects, and operations professionals who maintain the systems that the world depends on. The knowledge you have shared in public -- in forums, conference talks, articles, and documentation -- is what tells a book like this which topics actually matter in the enterprise rather than which are merely academically interesting.

The characters of Maria, Derek, Priya, James, Sarah, and Tomas are fictional composites. The production incidents, debugging sessions, and modernization projects they face are modeled on the kinds of situations COBOL professionals have described publicly, not on accounts given privately to this book.

The GnuCOBOL Project

The dual-platform approach that defines both this book and its predecessor would not be possible without GnuCOBOL. We owe special thanks to Simon Sobisch and the entire GnuCOBOL development team for maintaining a free, open-source COBOL compiler that makes the language accessible to learners worldwide.

GnuCOBOL's ability to run on personal computers -- Windows, macOS, and Linux -- removes the single largest barrier to COBOL education: the assumption that learning COBOL requires mainframe access. Every student who completes this book on a laptop owes a debt to the GnuCOBOL project.

IBM and the Z Ecosystem

We gratefully acknowledge IBM's contributions to COBOL education and the mainframe ecosystem. The IBM Z Xplore program provides essential access to z/OS environments for students working through the enterprise-focused chapters of this book. The IBM Enterprise COBOL development team's compiler documentation and redbooks served as critical reference material, particularly for the chapters on DB2, CICS, and IMS.

Learning COBOL Programming

This book stands on the foundation laid by Learning COBOL Programming (DataField.Dev, 2026), the introductory volume in the series. The pedagogical approach, the dual-platform philosophy, the exercise tier system, and the commitment to production-relevant instruction that define this volume were established in that predecessor.

Grace Hopper and the CODASYL Committee

We honor the memory and legacy of Rear Admiral Grace Murray Hopper and the CODASYL committee, whose vision of a readable, portable, business-oriented programming language created the foundation on which six decades of enterprise computing have been built. Every chapter of this book is an extension of the idea that programs should be comprehensible to the people who depend on them.

Corrections Welcome

This book was drafted with AI assistance and published free by DataField.Dev. Its code examples, and its DB2, CICS, and IMS content, should be checked against your own compiler and platform documentation. If you are an instructor, a working COBOL professional, or a student and you find an error, an outdated practice, or an example that does not compile, corrections and suggestions are welcome (see https://datafield.dev/about.html#contact). The errors that remain are the book's own.

To every COBOL programmer who has ever been handed a 10,000-line program with no documentation and told to "just figure it out": this book is for you.