IMS Mastery
The Complete Reference Course
IBM IMS (Information Management System) is one of the world's most proven hierarchical databases — powering banking, insurance, healthcare, and government systems for over 50 years. This course takes you from zero to production-ready, covering every IMS concept with practical COBOL DL/I examples.
IMS Foundations
4 modules
What is IMS? IBM Information Management System Introduction
History, purpose, and real-world use of IMS in banking, insurance, healthcare, and government mainframe environments.
Read article →IMS Architecture: Regions, Address Spaces, and Components
Deep dive into IMS control region, DLI region, BMP region, and how IMS manages databases and message queues on z/OS.
Read article →IMS vs DB2: When to Use Each on z/OS Mainframe
A practical comparison of IMS hierarchical databases and DB2 relational databases — strengths, limitations, and when each is the right choice.
Read article →IMS Hierarchical Data Model Explained with Examples
How IMS stores data in a tree-like parent-child hierarchy, root segments, dependent segments, and navigating hierarchical relationships.
Read article →IMS Database Design
5 modules
IMS DBD: Database Description Complete Guide
Writing and understanding IMS Database Description macros — DBDGEN, segment definitions, field definitions, and DBDLIB generation.
Read article →IMS Segments and Fields: Designing the Hierarchy
How to design IMS segment layouts, field definitions, key fields, sequence fields, and best practices for hierarchical data modelling.
Read article →IMS Access Methods: HSAM, HISAM, HDAM, HIDAM Explained
Complete guide to all four IMS access methods — sequential vs indexed vs direct, when to choose each, and performance implications.
Read article →IMS PSB and PCB: Program Specification Block Complete Guide
Defining Program Communication Blocks, sensitivity levels, processing options, PSBGEN, and how PCBs control database access in DL/I programs.
Read article →IMS Secondary Indexing: Complete Guide with Examples
How IMS secondary indexes work, XDFLD definition, index databases, pointer segments, and using secondary indexes for alternate access paths.
Read article →DL/I Programming
6 modules
IMS DL/I Calls: GU, GN, GNP Retrieval Commands
Master the three core IMS retrieval calls — Get Unique (GU), Get Next (GN), and Get Next within Parent (GNP) — with COBOL examples.
Read article →IMS DL/I ISRT, DLET, REPL: Modifying IMS Data
Insert, delete, and replace segments in an IMS database using ISRT, DLET, and REPL calls with complete COBOL programming examples.
Read article →IMS SSA: Segment Search Arguments Complete Guide
Writing unqualified and qualified SSAs, command codes, boolean operators, and how SSAs control segment selection in DL/I calls.
Read article →IMS COBOL Programming: Your First DL/I Program
Step-by-step guide to writing a COBOL program that uses DL/I calls — PCB mask, entry linkage, CALL DLI syntax, and status code handling.
Read article →IMS Qualified SSAs and Boolean Operations
Advanced SSA techniques — qualified SSAs with relational operators, multiple qualifications, boolean AND/OR, and nested SSA patterns.
Read article →IMS Cursor Positioning and Sequential Retrieval
How IMS maintains position in the database hierarchy, sequential retrieval with GN and GNP, and resetting position with GU calls.
Read article →IMS Transaction Manager
4 modules
IMS TM Architecture: Message Processing and MPPs
IMS Transaction Manager architecture — message queues, MPP regions, transaction routing, and how IMS TM handles online transactions.
Read article →IMS MFS: Message Format Service Complete Guide
Designing 3270 terminal screens with IMS MFS — MSG, FMT, DEV macros, MFSGEN, and using MFS to format input and output messages.
Read article →IMS BMP: Batch Message Processing Programs
Writing IMS BMP programs that access both IMS databases and message queues in a batch environment — use cases, JCL, and programming patterns.
Read article →IMS Fast Path: DEDBs and MSDBs Explained
IMS Fast Path for high-throughput applications — Data Entry Databases (DEDBs), Main Storage Databases (MSDBs), and Fast Path DL/I calls.
Read article →Administration and Career
3 modules
IMS Utilities and Recovery: Complete Operations Guide
Essential IMS utilities — DFSURGL0, DFSURUL0, database backup and recovery, image copy, reorganisation, and disaster recovery procedures.
Read article →IMS Performance Tuning and Monitoring
IMS performance analysis tools, buffer pool tuning, OSAM vs VSAM considerations, database reorganisation, and common bottleneck fixes.
Read article →50 IMS Interview Questions and Answers (2026)
Top 50 IMS interview questions covering architecture, DL/I programming, DBD/PSB/PCB, access methods, TM, and administration for mainframe roles.
Read article →Who Is This Course For?
Designed for every stage of the mainframe development career
Freshers
No IMS experience? Start with IMS Foundations to understand what IMS is, how hierarchical databases work, and why IMS is still critical in enterprise systems.
Junior Developers
Already writing COBOL? Level up with DL/I calls, SSA patterns, DBD/PSB/PCB design, and robust status code handling in your IMS programs.
Experienced Professionals
Deepen expertise with IMS Fast Path, MFS screen design, BMP programming, performance tuning, and interview preparation for senior mainframe roles.
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Start Learning IMS Today
IMS skills are among the rarest and highest-paid in mainframe development. Banks, insurers, and healthcare systems rely on IMS every day. Start Module 1 now — it is completely free.
Start Module 1: Introduction to IMS →