This article provides a high-level overview of IMS database concepts, terminology, and database design considerations. It covers the following topics: Overview Hierarchical versus Relational Databases Design Considerations...   Read Article.

IMS is a large application that runs on z/OS. There is a symbiotic relationship between IMS and z/OS. Both are tailored to provide the most efficient use of the hardware and software components. IMS runs as a z/OS subsystem and uses several address spaces: one controlling address space, several separate address spaces that provide IMS services, and...   Read Article.

The IMS system definition process: + Describes the IMS resources to IMS: * At installation time * When maintenance is applied * When standard application definition changes are required + Assumes a working knowledge of the z/OS...   Read Article.

IMS legacy systems reliably serve the core business processes in many of the world's largest corporations. Indeed, IMS supports a variety of business applications that directly affect customers through automated teller machines, credit card transactions, airline and hotel reservations, package tracking and delivery as well as ordinary financial accounting...   Read Article.

Multi-volume data sets have always been troublesome. The best thing is to avoid them at all costs. However, this is not an option because we have data sets larger than a 3390-3. So, we may have to live with that. This article attempts to give some advice for managing multi-volume OSAM data sets....   Read Article.

For the past few decades, the IMS database arena has been very quiet. The last major enhancements were the addition of VSAM support in the mid-1970s and the introduction of Fast Path databases in the late 1970s. OSAM was enlarged to allow a 4 GB size limit in the 1980s and again to 8 GB in the 1990s. The new century starts with a big bang. IMS 7.1...   Read Article.

This article describes some problems and considerations involved with recovering IMS systems. Important facets of recovery include automating wherever possible to reduce the likelihood of human error and ensuring business-critical applications are back online as quickly as possible with minimal data loss. Some background concepts may already be familiar...   Read Article.

This chapter discusses the IMS online environment, online application programs, backup, and recovery. It covers the following topics: IMS Online Environment Application Programs Backup and Recovery Database Recovery Control...   Read Article.

IMS continues to be a robust, reliable data server of choice in the enterprise; its ability to flawlessly execute billions of transactions provides evidence of its staying power. IMS prevails because it is reliable, dependable, and it works. Legacy applications and data persist because IBM continues investing in IMS and enhancing its functionality....   Read Article.

There are many reasons for the re-emergence of the mainframe as a viable processing platform. Probably the most important reason of all, however, was IBM's* decision to enable IMS for MVS Parallel Sysplex. The MVS Parallel Sysplex provides an easily scalable computing platform, which is more cost-efficient than the historical mainframe environment....   Read Article.

This article discusses IMS database organization, access methods, secondary indexes, and logical relationships. It covers the following topics: Control Blocks Access Methods Hierarchic Sequential Databases Hierarchic Direct Databases Fast Path Databases The Role of Secondary Indexes The Role of Logical...   Read Article.