CobolDemo-GITST Repository Overview

This repository contains an IBM i (AS/400) demonstration application that spans COBOL, RPG/RPGLE, CL, SQL, and DDS assets. The code appears to implement a light-weight CRM/order management workflow with customer, contact, order, distribution, and audit capabilities. The structure mirrors traditional IBM i source libraries, where each top-level directory corresponds to a source physical file (e.g., QCBLSRC for COBOL, QDDSSRC for DDS display/database definitions).

Directory Overview

• QCBLSRC – COBOL programs for contracts, customers, and transaction history maintenance.
• QRPGSRC – Fixed-format RPG programs for reporting and legacy batch processing.
• QRPGLESRC – ILE RPG modules for interactive UI, CRUD logic, and SQLRPGLE integration.
• QCLSRC / QCLLESRC – Control language programs orchestrating batch jobs, overrides, and emergency utilities.
• QCMDSRC – Custom command definitions for launching the RPG/CL drivers.
• QDDSSRC – DDS for display, printer, logical, and physical files, defining the UI and database schema.
• CPYBKSRC – COBOL copybooks shared across COBOL components.
• QQMQRYSRC – Query/400 definitions for quick reports.
• QSQLPRC / QSQLSRC – SQL procedures and DDL artifacts for incremental modernization.
• ASIMPLTEST – Ad hoc testing sources combining RPG, CL, and DDS snippets.
• Tooling and configuration lives under .idea and .ibmi.
• SSADM documentation resides in docs, including generated overviews, process models, and business rule catalogs.

Documentation Quality

After changing the repository documentation or the archaeology corpus, run make quality. The gate checks that the required archaeology documents exist, rejects unintended trailing whitespace in tracked Markdown and the Makefile, validates local archaeology links, and renders the corpus's Mermaid diagrams. A successful run exits with status zero and reports relative links: OK and Mermaid render: OK.

This gate validates documentation structure only. It does not compile IBM i sources or validate runtime or deployment behavior.

Key Concepts

• Data-Centric Design: DDS physical/logical files (QDDSSRC) underpin both COBOL and RPG programs. Many source members expect specific record formats (e.g., CONDET, CUSTS, STKMAS).
• Mixed UI Layers: Display files drive interactive screens, while CL programs manage overrides and job control. RPGLE modules often correspond to display file names (e.g., WWCUSTS.RPGLE works with WCUSTSD.DSPF).
• Copybook-Driven Data Sharing: COBOL programs rely on copybooks from CPYBKSRC to enforce record layouts.
• SQL Modernization Hooks: SQL procedures and SQLRPGLE sources show initial steps toward embedding SQL logic, offering footholds for migration.

Positive Findings

• Comprehensive coverage of customer/order lifecycle across multiple languages.
• SQLRPGLE and stored procedure samples demonstrate modernization awareness.
• Query/400 definitions provide concise documentation of reporting needs.

Negative Findings / Risks

• Heavy coupling to DDS record formats and indicators increases migration complexity.
• Sparse inline documentation; business rules must be inferred from code.
• Minimal automated testing—the ASIMPLTEST folder is informal and mixed-format.

Entanglement & Migration Notes

• Least entangled: QSQLSRC table definitions and QSQLPRC procedures have minimal dependencies and can be migrated to modern SQL services quickly. Query/400 definitions (QQMQRYSRC) are also self-contained snapshots of data needs.
• Moderately entangled: COBOL copybooks (CPYBKSRC) and standalone CL utilities (e.g., TESTWIMX.CLLE) can move independently but interact via job control conventions.
• Most entangled: DDS display files (QDDSSRC) and their paired RPGLE programs rely on IBM i subfile indicators and program-to-display contracts; migrating them requires substantial UI rethinking.

Migration Suggestions

1. Expose core data via APIs: Externalize key tables (CUSTS, CONHDR, CONDET, etc.) using REST services backed by the SQL DDL in QSQLSRC. Legacy RPG/COBOL modules could call new HTTP endpoints via sockets or HTTP APIs instead of direct file I/O.
2. Modularize business rules: Refactor COBOL programs like ZBCONDET and RPGLE modules like WWCONDET into service routines callable from both legacy and modern environments. Gradually replace file I/O with SQL views or stored procedures from QSQLPRC.
3. Wrap CL orchestration: Re-implement batch CL flows (see QCLSRC) in modern schedulers while keeping IBM i overrides temporarily. Provide HTTP triggers or message queues for the hardest-to-migrate interactive screens.

---

Tip for future agents: consult these context.md files first—they summarize dependencies and modernization paths. Update the relevant context.md whenever you modify code in a directory to keep this index trustworthy.