IBM Information Management System
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|
| Initial release | 1966 |
|---|---|
| Stable release |
IMS V14 / October 5, 2015
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| Development status | Active |
| Operating system | z/OS V2.1 or later |
| Platform | IBM System z |
| Type | Database & transaction processing subsystem |
| License | proprietary |
| Website | IMS V14 Announcement PDF |
IBM Information Management System (IMS) is a joint hierarchical database and information management system with extensive transaction processing capabilities.
IBM designed the IMS with Rockwell and Caterpillar starting in 1966 for the Apollo program, where it was used to inventory the very large bill of materials (BOM) for the Saturn V moon rocket and Apollo space vehicle.
The first "IMS READY" message appeared on an IBM 2740 terminal in Downey, California, on 14 August 1968. In the interim period, IMS has undergone many developments as IBM System/360 technology evolved into the current z/OS and System z9 and z10 technologies. For example, IMS now supports the Java programming language, JDBC, XML, and, since late 2005, web services.
Vern Watts was IMS's chief architect for many years. Watts joined IBM in 1956 and worked at IBM's Silicon Valley development labs until his death on April 4, 2009. He had continuously worked on IMS since the 1960s.
The IMS Database component stores data using a hierarchical model, which is quite different from IBM's later released relational database, DB2. In IMS, the hierarchical model is implemented using blocks of data known as segments. Each segment can contain several pieces of data, which are called fields. For example, a customer database may have a root segment (or the segment at the top of the hierarchy) with fields such as phone, name, and age. Child segments may be added underneath another segment, for instance, one order segment under each customer segment representing each order a customer has placed with a company. Likewise, each order segment may have many children segments for each item on the order. Unlike other databases, you do not need to define all of the data in a segment to IMS. A segment may be defined with a size of 40 bytes but only define one field that is six bytes long as a key field that you can use to find the segment when performing queries. IMS will retrieve and save all 40 bytes as directed by a program but may not understand (or care) what the other bytes represent. In practice, often all data in a segment may map to a COBOL copybook. Besides DL/I query usage, a field may be defined in IMS so that the data can be hidden from certain applications for security reasons. The database component of IMS can be purchased standalone, without the transaction manager component, and used by systems such as CICS.
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