COBOL Course

Lesson 1 • Mainframe Architecture Overview

Introduces mainframe hardware concepts, operating systems, and job execution models. Connects mainframe architecture to how COBOL programs are compiled and run.

Lesson 2 • History and Purpose of COBOL

Covers COBOL's origins, design philosophy, and business-oriented syntax goals. Provides context for understanding why COBOL dominates legacy enterprise systems.

Lesson 3 • COBOL Program Structure at a Glance

Previews the four-division structure and fixed-format layout of a COBOL source file. Sets expectations for the syntax patterns explored in subsequent chapters.

Lesson 1 • Procedure Division Basics

Introduces COBOL statements, paragraphs, and sections within the Procedure Division. Students write sequential logic that reads, processes, and displays data.

Lesson 2 • Data Division Fundamentals

Teaches FILE SECTION, WORKING-STORAGE SECTION, and LINKAGE SECTION declarations. Data Division mastery is prerequisite for all data manipulation in later chapters.

Lesson 3 • Identification and Environment Divisions

Covers required program metadata and file-system linkage declarations. Establishes how COBOL programs identify themselves and connect to external resources.

Lesson 4 • COBOL Reserved Words and Coding Rules

Covers reserved word restrictions, continuation rules, and comment syntax. Avoiding reserved word conflicts and formatting errors is essential for clean compilation.

Lesson 1 • Arithmetic Statements

Teaches ADD, SUBTRACT, MULTIPLY, DIVIDE, and COMPUTE with ROUNDED and ON SIZE ERROR options. Students perform precise calculations required in financial and reporting programs.

Lesson 2 • MOVE Statement Variations

Covers elementary, group, and corresponding MOVE operations and their implicit conversion rules. Understanding MOVE behavior prevents silent data corruption.

Lesson 3 • Condition Names and Data Validation

Covers 88-level condition names and VALUE clauses for readable data validation. Condition names simplify conditional logic introduced in the next chapter.

Lesson 1 • EVALUATE Statement

Teaches EVALUATE as COBOL's multi-way branch, replacing complex nested IFs. Students implement decision tables cleanly using WHEN clauses and ALSO phrases.

Lesson 2 • GO TO and Structured Alternatives

Explains GO TO usage, its risks, and structured replacements using PERFORM. Students learn to refactor unstructured legacy code into maintainable logic.

Lesson 3 • IF, ELSE, and Nested Conditions

Covers IF-ELSE syntax, nested IF blocks, and the END-IF scope terminator. Proper nesting and scope termination prevent logic errors in multi-branch programs.

Lesson 1 • Opening, Reading, and Closing Files

Teaches OPEN, READ, and CLOSE statements with AT END and FILE STATUS handling. Correct open/close sequencing and status checking prevent data loss and runtime errors.

Lesson 2 • File Organization and Access Modes

Covers sequential, indexed, and relative file organizations and their access mode options. Choosing the correct organization determines performance and flexibility of file operations.

Lesson 3 • Writing and Rewriting Records

Covers WRITE, REWRITE, and DELETE statements for output and update operations. Students build programs that create and modify sequential and indexed files.

Lesson 4 • Report Writing with WRITE AFTER ADVANCING

Covers line spacing, page control, and heading logic using WRITE AFTER ADVANCING. Students produce formatted printed reports from sequential file data.

Lesson 1 • Variable-Length Tables with OCCURS DEPENDING ON

Introduces OCCURS DEPENDING ON for tables whose size varies at runtime. This technique handles variable-record-count structures common in data exchange files.

Lesson 2 • Defining Tables with OCCURS

Covers OCCURS clause syntax, fixed-length tables, and subscript-based access. Tables are essential for holding reference data and accumulating totals in batch programs.

Lesson 3 • INDEXED BY and SET Statement

Teaches index data items, the SET statement, and index arithmetic for table navigation. Indexes provide more efficient table access than subscripts in large datasets.

Lesson 1 • Nested Programs and Scope

Introduces COBOL nested programs, GLOBAL and EXTERNAL data, and scope rules. Nested programs enable encapsulation within a single source file for smaller modules.

Lesson 2 • Copybooks and Code Reuse

Covers COPY statement usage, REPLACING phrase, and copybook library management. Copybooks enforce consistent record layouts across all programs in an application.

Lesson 3 • CALL Statement and Parameter Passing

Covers CALL BY REFERENCE, BY CONTENT, and BY VALUE parameter modes. Correct parameter mode selection prevents unintended data modification in calling programs.

Lesson 4 • LINKAGE SECTION in Subprograms

Teaches how subprograms declare received parameters in the LINKAGE SECTION. Students write callable subprograms that accept and return data correctly.

Lesson 1 • SQL SELECT and Cursor Processing

Covers singleton SELECT, cursor declaration, OPEN, FETCH, and CLOSE operations. Cursors allow row-by-row processing of multi-row query results in COBOL programs.

Lesson 2 • Transaction Control and Error Handling

Covers COMMIT, ROLLBACK, and SAVEPOINT within COBOL batch and online programs. Proper transaction boundaries ensure data integrity during partial-failure scenarios.

Lesson 3 • Performance Tuning and Best Practices

Addresses efficient SQL coding, COBOL compiler options, and data structure optimization. Students apply tuning techniques that reduce CPU and I/O costs in production jobs.

Lesson 4 • Embedded SQL Fundamentals

Introduces EXEC SQL blocks, host variables, and the SQLCA communication area. Embedded SQL enables COBOL programs to interact directly with relational databases.