IMS serves more than 95 percent of Fortune 1000 companies, manages 15,000,000 gigabytes of production data, and supports more than two hundred million users per day. The brand-new IBM IMS Version 9 is not just the world's #1 platform for very large online transaction processing: it integrates with Web application server technology to enable tomorrow's most powerful Web-based applications. Now, for the first time in many years, there's a completely up-to-date guide to understanding IMS in your business environment.

An Introduction to IMS covers

Installing and configuring IMS Version 9

Understanding and implementing the IMS hierarchical database model

Understanding and working with the IMS Transaction Manager

Mastering core application programming concepts, including program structure and IMS control blocks

Taking advantage of IMS 9 Java programming enhancements

Working with the IMS Master Terminal

Administering IMS: system definition, customization, logging, security, operations, and more

Running IMS in a Parallel Sysplex(r) environment

Whether you've spent a career running IMS or you are encountering IMS for the first time, this book delivers the insights and skills you need to succeed--as an application designer, developer, or administrator.

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Accessing IBM's Information Management System

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Figures xiii

Tables xvii

Foreword xix

Preface xxiii

Acknowledgments xxv

About the Authors xxvii

Part I Overview of IMS 1

Chapter 1 IMS: Then and Now 3

History of IMS: Beginnings at NASA 3

Is IMS Still Strategic for Customers and IBM? 4

Chapter 2 Overview of the IMS Product 9

IMS Database Manager 10

IMS Transaction Manager 12

IMS System Services 13

IMS Documentation 13

Hardware and Software Requirements for IMS 13

Chapter 3 Accessing IMS 17

Accessing IMS from Application Programs 17

Accessing IMS from Other Products 22

Chapter 4 IMS and z/OS 27

How IMS Relates to z/OS 27

Structure of IMS Subsystems 28

Running an IMS System 43

Running Multiple IMS Systems 44

How IMS Uses z/OS Services 45

Chapter 5 Setting Up and Running IMS 49

Installing IMS 49

Defining an IMS System 51

IMS Startup 51

IMS Logging 54

IMS Utility Programs 54

IMS Recovery 55

IMS Shutdown 56

Part II IMS Database Manager 59

Chapter 6 Overview of the IMS Database Manager 61

Functions of the IMS Database Manager 61

Implementation of IMS Databases 62

Storing Data in IMS and DB2 UDB for z/OS 64

Storing XML Data in IMS 65

Chapter 7 Overview of the IMS Hierarchical Database Model 67

IMS Hierarchical Database Basics 68

Basic Segment Types 72

Sequence Fields and Access Paths 73

Chapter 8 Implementing the IMS Hierarchical Database Model 83

Segments, Records, and Pointers 84

IMS Hierarchical Access Methods 87

Operating System Access Methods 109

IMS Checkpoints 111

Locking Data 114

Chapter 9 Data Sharing 119

How Applications Share Data 120

DBRC and Data Sharing 121

Chapter 10 The Database Reorganization Process 123

Purpose of Database Reorganization 124

When to Reorganize Databases 124

Overview of the Database Reorganization Process 128

Chapter 11 The Database Recovery Process 151

Determining When Recovery Is Needed 151

Overview of the Database Recovery Process 152

IMS Backup and Recovery Utilities 153

Part III IMS Transaction Manager 167

Chapter 12 Overview of the IMS Transaction Manager 169

IMS TM Control Region 170

IMS TM Messages 171

IMS Transaction Flow 173

IMS TM Network Overview 175

The Data Communication Control (DCCTL) Environment 189

Operating an IMS Network 190

Chapter 13 How IMS TM Processes Input 195

Input Message Types 195

Terminal Types 197

Input Message Origin 197

Terminal Input Destination 197

Message Queuing 198

Message Scheduling 206

Transaction Scheduling 208

Part IV IMS Application Development 215

Chapter 14 Application Programming Overview 217

Java Programs 218

Application Program Structure 218

IMS Setup for Applications 230

IMS Application Programming Interfaces 235

IMS Application Calls 235

Accessing DB2 for z/OS Using a Resource Translation Table 237

IMS System Service Calls 237

Testing IMS Applications 239

Chapter 15 Application Programming for the IMS Database Manager 241

Introduction to Database Processing 241

Processing a Single Database Record 246

COBOL and PL/I Programming Considerations 261

Processing Databases with Logical Relationships 265

Processing Databases with Secondary Indexes 267

Loading Databases 269

Using Batch Checkpoint/Restart 275

Chapter 16 Application Programming for the IMS Transaction Manager 281

Application Program Processing 281

Transaction Manager Application Design 289

Chapter 17 Editing and Formatting Messages 297

Message Format Service 298

Basic Edit Function 308

Chapter 18 Application Programming in Java 311

Describing an IMS Database to the IMS Java Function 312

Supported SQL Keywords 313

Developing JMP Applications 314

Developing JBP Applications 315

Enterprise COBOL Interoperability with JMP and JBP Applications 316

Accessing DB2 UDB for z/OS Databases from JMP or JBP Applications 317

Developing Java Applications That Run Outside of IMS 317

XML Storage in IMS Databases 321

Part V IMS System Administration 327

Chapter 19 The IMS System Definition Process 329

Overview of the IMS System Definition Process 330

IMS System Definition Macros 335

The Extended Terminal Option (ETO) 338

Chapter 20 Customizing IMS 347

What You Can Customize 348

Naming the Routines 349

Changeable Interfaces and Control Blocks 349

IMS Standard User Exit Parameter List 349

Binding the Routines 349

Saving Registers 350

IMS Callable Services 350

Considering Performance 351

Summary of IMS Exit Routines 352

Chapter 21 IMS Security 361

History of IMS Security 361

Security Overview 361

Securing Resources 363

Chapter 22 IMS Logging 367

IMS System Checkpoints 367

Database Recovery Control Facility (DBRC) 368

IMS Log Components 368

Chapter 23 Database Recovery Control (DBRC) Facility 375

Overview of DBRC 376

DBRC Tasks 376

DBRC Components 377

When Should You Use DBRC? 378

Communicating with DBRC 379

DBRC Functions 381

Overview of the RECON Data Sets 395

Defining and Creating the RECON Data Sets 398

Initializing the RECON Data Sets 399

Allocating the RECON Data Sets to an IMS System 400

Maintaining the RECON Data Sets 401

Reorganizing RECON Data Sets 403

Recreating the RECON Data Sets 404

Summary of Recommendations for RECON Data Sets 404

Chapter 24 Operating IMS 405

Monitoring the System 405

Processing IMS System Log Information 406

Choosing Tools for Detailed Monitoring 413

Executing Recovery-Related Functions 419

Modifying and Controlling System Resources 421

Controlling Data Sharing 428

Controlling Log Data Set Characteristics 431

Connecting and Disconnecting Subsystems 436

Chapter 25 IMS System Recovery 439

Overview of Extended Recovery Facility (XRF) 440

Overview of Remote Site Recovery (RSR) 440

Comparison of XRF and RSR 441

Summary of When to Use XRF or RSR 442

Chapter 26 IBM IMS Tools 443

Database Administration Tools 443

Application Management Tools 447

Performance Management Tools 450

Recovery Management Tools 452

Information Integration Management Tools 455

Utilities Management Tools 456

TM Management Tools 461

Miscellaneous IMS Tools 463

Part VI IMS in a Parallel Sysplex Environment 465

Chapter 27 Introduction to Parallel Sysplex 467

Goals of a Sysplex Environment 468

IMS and the Sysplex Environment 469

Other Advantages of Running IMS TM in a Sysplex Environment 485

Chapter 28 IMSplexes 495

Components of an IMSplex 496

Requirements for an IMSplex 498

Operating an IMSplex 499

Part VII Appendixes 501

Appendix A Glossary 503

Appendix B Acronyms and Abbreviations Used in This Book 511

Appendix C Notices 517

Appendix D Bibliography 521

Index 525

Preface

Untitled Document

IBM Information Management System (IMS) is one of the world's premiere software products. Period. IMS is not in the news and is barely mentioned in today's computer science classes, but it has been and, for the foreseeable future, will continue to be, a major, crucial component of the world's software infrastructure.

From its beginnings with NASA, IMS has provided the foundation that enables government agencies and businesses to manage, access, manipulate, and exploit their vast stores of data. As the Information Age evolves and matures, so does IMS.

The purpose of this book is twofold.

To introduce IMS to those who have not yet heard about it and provide basic education about this cornerstone product.

To reintroduce IMS to the computer science field in general.

Prerequisite Knowledge

Before reading this book

You should be able to describe the fundamentals of data processing, including the function of operating systems, access methods, and job control language (JCL). Specifically, you should be familiar with the z/OS operating system or any of its predecessors. The authors of this book assume that most readers are data processing professionals.

You should also have access to the IMS Version 9 library because there are many references in this book to the IMS Version 9 manuals. These manuals are listed in the Bibliography. You can either read the IMS manuals online or download them from the Library page of the IMS Web site. Go to www.ibm.com/ims and click on the "Library" link in the navigation pane on the left side of the page.

Foreword

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Index

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Introduction to IMS, An: Your Complete Guide to IBM's Information Management System

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