Objectives

This course is a comprehensive introduction to IMS. It provides ideal cross-training for application support specialists from disciplines such as CICS, COBOL, JAVA, or DB2. The course introduces and explains all areas of IMS databases in both the batch and online environments, including data access using the DL/I language interface and the maintenance of data integrity using the DBRC feature.

On successful completion of this course, attendees will be able to:

• describe the architecture of IMS batch and online systems
• analyse database and communication calls
• identify appropriate logical and physical database design features
• describe the structure of secondary indexes and logical relationships
• use IMS utilities to backup, restore, and reorganize the database
• discuss the facilities available in IMS to provide data integrity and system availability.
• trace the flow of a transaction through an IMS system.

Main topics

• Introduction to IMS

Why Use a Database?; Database types; Hierarchical terminology; Processing path; Accessing data; Database implementation; IMS online environment; Message Format Services (MFS); Utilities; Logging; Operational responsibilities.

• Introduction to batch programming

DL/I Language Interface; Program Specification Block (PSB); IMS Call Format; Function code; Record retrieval Workshop.

• Advanced database programming

Update processing; Command codes; PCB Addressing; Boolean SSAs.

• Database environment

Program Specification Block (PSB); PSB statements; PCB; PROCOPTs; PSB generation; ACB generation; PSB/program relationships; Batch JCL.

• Database implementation

DBD; Database Organisation and Access Methods.

Secondary indexing; Secondary data structure; Stand-Alone processing; Things to consider; Logical relationships.

An introduction to HALDB features and processing options.

• Database backup and recovery

Logging; Image Copy; Reorganisation; Database Recovery Control (DBRC); associated tools and utilities.

• IMS/TM concepts & facilities

IMS/DC configuration; Control (CTL) region; DL/I Separate Address Space (DLISAS); Database Recovery Control (DBRC); Message Processing Region (MPR); Batch Message Processing (BMP) region; Message scheduling; Logging.

• IMS online programming

Message Processing Program (MPP); Transaction codes & flow; Input message segment; Output message segment; IMS message calls; IO PCB mask; Common status codes.

Alternate PCB; Transaction switching; Conversational programming; Using Checkpoint/Restart.

• Message Format Services

MFS control blocks; DIF/DOF coding; MID/MOD coding; Attributes; Message management.

• Fast Path

General characteristics; Fast Path EMH; Data Entry Database (DEDB); Main Storage Database.

• Online IMS system recovery and restart

Logging; Restart Data Set (RDS); Archiving; Contents of the Log; Normal restart; Emergency restart.

• Sharing data and data sharing

Sharing access - the problem; Sharing access - solutions; Control region / DLISAS; Program isolation; Locking; Deadlock resolution; Data sharing; Database-Level Sharing; Block-level sharing; DBCTL.

• IMS operations

Operational considerations; Operations planning; Starting IMS; Stopping IMS; Online change facility; Controlling IMS.

• IMS performance management

DB performance; DB monitor; Database buffer pools; DC performance.