About DBala Online

DBala Online is a practical mainframe learning site maintained by Balasubramanian Duraiswamy, a Senior Mainframe Developer with experience in COBOL, JCL, DB2, CICS, VSAM, production support, documentation, testing, and AI-assisted developer productivity.

The site focuses on clear explanations for learners and working developers. The goal is to make mainframe concepts easier to understand through examples, production-style scenarios, and modernization notes.

Topics covered

• COBOL batch programming
• JCL and job flow control
• DB2 SQL and access paths
• CICS transaction processing
• VSAM datasets
• Mainframe modernization and AI-assisted documentation