Information Management System (IMS) is a joint hierarchical database and information management system. A hierarchical database is a kind of database management system that links records together in a tree data structure such that each record type has only one owner, e. ... Information management is the handling of knowledge acquired by one or many disparate sources in a way that optimizes access by all who have a share in that knowledge or a right to that knowledge. ...

IMS was designed by IBM working with Rockwell and Caterpillar in 1966 for the Apollo program. It was used to track the very large Bill of Materials for the Saturn V. International Business Machines Corporation (IBM, or colloquially, Big Blue) (NYSE: IBM) (incorporated June 15, 1911, in operation since 1888) is headquartered in Armonk, New York, USA. The company manufactures and sells computer hardware, software, and services. ... Rockwell International was the ultimate incarnation of a series of companies under the sphere of influence of Willard Rockwell, who had made his fortune after the invention and successful launch of a new bearing system for truck axles in 1919. ... Caterpillar Inc. ... 1966 was a common year starting on Saturday (link goes to calendar) // Events January January 1 - In a coup, Colonel Jean-Bédel Bokassa ousts president David Dacko and takes over the Central African Republic. ... Description Role: Earth and Lunar Orbit Crew: 3; CDR, CM pilot, LM pilot Dimensions Height: 36. ... This article needs cleanup. ... The Saturn V (popularly known as the Moon Rocket) was a multistage liquid-fuel expendable rocket used by NASAs Apollo and Skylab programs. ...

The first "IMS READY" message was displayed on an IBM 2740 terminal in Downey, California on 14 August 1968. IMS is still running thirty five years later and over time has seen some interesting developments as IBM S/360 technology developed into the current z/OS operating system. Downey is a city located in Los Angeles County, California, United States, 21 km (13 miles) southeast of downtown Los Angeles. ... August 14 is the 226th day of the year in the Gregorian Calendar (227th in leap years), with 139 days remaining. ... 1968 was a leap year starting on Monday (the link is to a full 1968 calendar). ... z/OS is a 64-bit server operating system from IBM. It is the successor to the IBM mainframe operating system OS/390, combining MVS and UNIX System Services (a POSIX-compliant mainframe implementation of UNIX formerly known as MVS Open Edition). ...

There are three basic forms of hierarchical databases:

1. Full Function databases

• Full function, which is basically the same Data Language/1 (DL/I) databases as developed for Apollo. Full function databases can have primary and secondary indexes and are accessed using DL/I calls from your application program.
• Full function databases can have a variety of access methods, although Hierarchical Direct (HDAM) and Hierarchical Indexed Direct (HIDAM) prevail.
• The other formats are Simple Hierarchical Indexed Sequential (SHISAM), Hierarchical Sequential (HSAM) and Hierarchical Indexed Sequential (HISAM).
• Data in full function databases can be stored using VSAM (a native MVS access method) or Overflow Sequential (OSAM), an IMS specific access method that optimizes the channel program for IMS access. OSAM has the advantage that there is special handling in IMS for sequential access of OSAM databases (OSAM Sequential Buffering) which has a performance benefit.

2. IMS also has fast path databases - Data Entry Databases (DEDB) and Main Storage Databases (MSDB). These two types of database don't allow for any indexation, but are optimized for extremely high transaction rates. With modern releases of IMS MSDBs can be replaced by a Virtual Storage Option (VSO) DEDB. Data Language/1 (DL/1) is the language system used to access IBM’s IMS databases, and its data communication system. ... Virtual Sequential Access Method (VSAM) is an IBM disk file storage scheme first used in the S/370 and virtual storage. ...

3. And now High Availability Large Database (HALDB); which was introduced with IMS V7.1. This is an extension of IMS full function databases to provide better availability, better handling of extremely large data volumes (and with IMS Version 9 to provide online re-organization).

IMS is also a transaction manager. A transaction manager interacts with an end user (connected through VTAM or TCP/IP) and like a web server running a CGI program provides an interface to query or update IMS or DB2 databases. IMS uses a messaging and queuing paradigm. A transaction entered from a terminal is received by the IMS control program and stored on a message queue (in storage or on a dataset). When a transaction has been queued IMS invokes its scheduler to start the user's application program in a message processing region. The message processing region retrieves the transaction from the IMS message queue processes it reading and updating IMS and DB2 databases; then, if required enqueues a response message back onto the IMS message queue. Once the output message is complete and available the IMS control program sends it back to the originating terminal. The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... Common Gateway Interface (CGI) is an important World Wide Web technology that enables a client web browser to request data from a program executed on the Web server. ... DB2 is IBMs family of information management software products. ... A Message queue is a software-engineering component used for inter-process communication or for server-to-server communication. ...

When withdrawing money from an automated teller machine (ATM), there is a fair chance that a transaction will have run in an IMS system. Outdoor ATMs may be free-standing, like this kiosk, or built into the side of banks or other buildings For other uses of ATM, see ATM. An automatic teller machine or automated teller machine (ATM) is an electronic device that allows a banks customers to make cash withdrawals and...

Fast path databases DEDB can only be built on top of VSAM. DLI databases can be built on top of either VSAM or OSAM (with some restrictions depending on database organization) VSAM has a physical addressable limit of 4GB (note: the maximum size of a VSAM dataset has been increased to 128TB in recent versions of z/OS but IMS still limits a VSAM database dataset to 4GB) and OSAM has a physical limit of 8GB. VSAM and OSAM are usually referred to as the Access Method, the IMS "logical" view of the database is referred to as the database "organization" (HDAM, HIDAM, HISAM, ...). Internally the data is linked using 4 byte pointers or addresses in the database datasets (DBDS) the pointers are referred to as RBA's (relative byte address).

External links

• IMS Family - IBM Software
• Description from the [Software History Dictionary]
• History of IMS