COBOL Mastery
The only complete COBOL reference built for the modern mainframe stack. From your first program to production DB2 and CICS integration — fresher to experienced.
Who Is This For?
Zero COBOL experience. Learn from the ground up — syntax, structure, and your first working programs.
Know the basics but need depth on file handling, table processing, and DB2/CICS integration.
Reference-level coverage of modern COBOL features, performance patterns, and interview preparation.
COBOL Programming Tutorial for Beginners
History, structure, and why COBOL still powers the global financial system.
Read module →Is COBOL Dead? The Evergreen Guide for 2026
Data-driven case for COBOL's market dominance, talent gap, and career upside.
Read module →Free COBOL Compiler: GnuCOBOL Setup Guide
Install GnuCOBOL on Windows, Linux, and macOS and run your first program.
Read module →COBOL Program Structure: Divisions, Sections, and Paragraphs
The four divisions, how COBOL compiles, and the anatomy of every COBOL program.
Read module →COBOL Data Division: PIC Clauses, Levels, and Data Types
Level numbers, PIC X/9/S, COMP/COMP-3, FILLER, and the data hierarchy in depth.
Read module →COBOL Working Storage: 88 Condition Names, REDEFINES, VALUE
WS best practices, condition names, REDEFINES, OCCURS in working storage.
Read module →COBOL Arithmetic: ADD, SUBTRACT, MULTIPLY, DIVIDE, COMPUTE
All arithmetic verbs, ROUNDED, ON SIZE ERROR, and COMPUTE expressions.
Read module →COBOL Control Flow: IF, EVALUATE, PERFORM Loops
IF/ELSE/END-IF, nested conditions, EVALUATE TRUE, PERFORM UNTIL/VARYING/TIMES.
Read module →COBOL String Handling: STRING, UNSTRING, INSPECT, FUNCTION
Complete guide to string manipulation, inspection, and the FUNCTION catalogue.
Read module →COBOL File Handling: Sequential QSAM File I/O
SELECT, FD, OPEN, READ, WRITE, REWRITE, DELETE, CLOSE, AT END patterns.
Read module →COBOL Table Handling: OCCURS, SEARCH, SEARCH ALL
Arrays, INDEXED BY, SET, linear SEARCH, and binary SEARCH ALL in COBOL.
Read module →COBOL SORT and MERGE: Complete Guide
SORT and MERGE statements, SD entry, INPUT/OUTPUT PROCEDURE for complex sorts.
Read module →COBOL Subprograms: CALL, USING, and LINKAGE SECTION
Static vs dynamic CALL, BY REFERENCE vs CONTENT, building reusable modules.
Read module →COBOL Copybooks: COPY, REPLACING, and Library Management
COPY statement, REPLACING clause, copybook conventions, DFHAID/SQLCA examples.
Read module →COBOL Embedded SQL: DB2 Integration Complete Guide
EXEC SQL, host variables, cursors, SQLCA, and the precompile-bind workflow.
Read module →COBOL in CICS: Pseudo-Conversational Programming
EXEC CICS commands, EIB, COMMAREA, SEND/RECEIVE MAP in CICS COBOL programs.
Read module →JCL for COBOL: Compile, Link-Edit, and Execute
Full JCL to compile, DB2 precompile, link-edit, and run COBOL on z/OS.
Read module →Modern COBOL Features: JSON, XML, and FUNCTION Catalogue
JSON PARSE/GENERATE, XML PARSE, intrinsic functions, and OO COBOL overview.
Read module →COBOL vs Java: Mainframe Modernization Guide
Technical comparison, decimal precision, zIIP offload, and the hybrid approach.
Read module →50 COBOL Interview Questions and Answers (2026)
Comprehensive Q&A covering all COBOL topics from fresher to senior level.
Read module →Ready to master COBOL?
The language that runs the world's financial systems. Start today and build skills that pay a premium for decades.