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Database 2 (DB2)

IBM's flagship relational database management system. Although it is still most commonly referred to as DB2 the actual name is now "Universal Data Base" and is available for a number of different platforms and operating systems including z/OS.

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Database Control (DBCTL)

A component of the IMS DM software product, which allows access to IMS full-function databases and Direct Entry Databases (DEDB) from one or more transaction management systems i.e. CICS and IMS TM.

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Data Tables

CICS Data Tables enables files i.e. VSAM KSDS to be loaded into a dataspace (in memory) where they can be accessed far more quickly. CICS supports two types of Data Tables:

• CICS Maintained Data Tables (CMDT)
• User Maintained Data Tables (UMDT)

Data Tables can be shared in a MRO environment and also in a parallel sysplex environment, where the Data Tables can be stored and shared using the Coupling Facility (CF), they are then referred to as Coupling Facility Data Tables (CFDT).

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Direct Access Storage Device (DASD)

The name given to a storage device, which can be accessed (read, written etc.) directly as opposed to sequentially. A disk is generally accessed directly, that is the disk head is positioned exactly where the dataset or file begins on the disk. The exact position of each dataset or file on a disk is contained in the VTOC of the device. In contrast tapes and cartidges are accessed sequentially, that is the tape has to be read from the beginning until it reaches the required dataset or file.

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Distributed Program Link (DPL)

Is a "call" or "link" command supported by CICS Inter-Region Communication (IRC) enabling a program in one CICS region to link (pass control and anticipate return) to a program in another CICS region. It is also supported by the External CICS Interface (EXCI) to provide the same function from an MVS address space.

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