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Further Reading — Chapter 4: Data Description Mastery

IBM Documentation

  • Enterprise COBOL for z/OS Language Reference — Chapter on "Data Description Entry." The definitive reference for every clause discussed in this chapter. Available free at the IBM Documentation website.

  • Enterprise COBOL for z/OS Programming Guide — "Defining Data" section. Provides practical guidance on storage allocation, alignment, and performance implications of USAGE choices.

  • IBM z/Architecture Principles of Operation — Chapter on "Packed Decimal Instructions." For readers who want to understand exactly how the hardware executes COMP-3 arithmetic.

Textbooks

Online Resources

  • GnuCOBOL Programmer's Guide — Open-source COBOL compiler documentation. Covers data description with notes on differences from Enterprise COBOL. Free at gnucobol.sourceforge.io.

  • IBM Z Xplore — Free hands-on learning platform for mainframe development. Includes exercises on data description and record layout design. ibm.com/it-infrastructure/z/education/zxplore

Articles and Papers

  • Garfunkel, J. "Record Layout Design Patterns in COBOL." — A practitioner's guide to designing maintainable record layouts, with patterns for variant records, audit trails, and versioning.

  • "EBCDIC, Packed Decimal, and Binary: Understanding Mainframe Data Formats." IBM Developer. — Essential reading for understanding how DISPLAY, COMP, and COMP-3 data is physically represented on z/OS.

Topics for Further Exploration

  • COBOL 2002/2014 enhancements: The newer standards add USAGE NATIONAL for Unicode, USAGE OBJECT REFERENCE for OO COBOL, and extended PICTURE symbols. If your shop uses a modern compiler, explore these additions.

  • DFSORT and ICETOOL: IBM's sort utilities can manipulate packed decimal, binary, and zoned decimal fields directly in JCL without COBOL. Understanding USAGE formats is essential for writing SORT control statements.

  • DB2 data type mapping: How COBOL PICTURE and USAGE map to DB2 column types (CHAR, DECIMAL, INTEGER, etc.) is covered in Chapter 27. Understanding data description is prerequisite to effective embedded SQL.