Rational Developer for System z
PL/I for Windows, Version 7.6, Programming Guide

Workstation VSAM data sets

The PL/I workstation products support VSAM file organization. There are three types of VSAM data sets on the workstation:

The PL/I workstation products currently support the following methods for accessing VSAM data sets:

DDM access method
DDM data sets are record-oriented files as defined by the Distributed Data Management Architecture. Workstation VSAM data sets that use the DDM access method can exist on local systems. You can compile and run most existing mainframe programs that reference mainframe VSAM data sets.

A DDM keyed data set is represented by two files—one called the base, and the other called the prime index. The records of the data set are kept in the base; the prime index contains information about the primary keys of the data set. When you create a DDM keyed data set, you specify the name of the base; DDM generates a name for the prime index, which it derives from the name of the base.

When you use DDM data sets, you do not need to be concerned about record length, except that your records cannot exceed the maximum specified length.

You can compile and run most existing mainframe programs that reference mainframe VSAM data sets by creating the appropriate workstation VSAM data set on your PC before running the program.

ISAM access method
Unless otherwise specified, the term ISAM in this chapter refers to the ISAM local access method and not mainframe ISAM. ISAM data sets are stored in one file and can exist on local file systems only.
BTRIEVE access method (Windows only)
The BTRIEVE access method is provided to allow you to use PL/I input and output statements to access files created under CICS. There is currently no PL/I support for BTRIEVE segmented and multiple keys.

BTRIEVE data sets are stored in one file and can exist on local file systems only.

REMOTE access method on Windows
The REMOTE access method is provided to allow you to remotely access data files on the mainframe.

Detailed information on workstation VSAM is found in Defining and using workstation VSAM data sets.


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