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VSAM – Introduction to VSAM z/OS 2.5


1 hour



This course provides the learner with a basic understanding of the VSAM access method and VSAM data sets on z/OS. It introduces what VSAM is and when it is used. It includes information on the different VSAM data set types, when each is used, and their internal structure.


This course is oriented to Application Programmers, Systems Programmers and Operations staff. However, anyone needing to understand VSAM data sets will benefit from this course.


Successful completion of the following Interskill courses:

  • IBM (z/OS) – The Evolving Mainframe
  • IBM (z/OS) – Working with the Mainframe


After completing this course, the student will be able to:

  • Describe the purpose of VSAM
  • Explain the structure of VSAM data sets
  • Identify the role of VSAM indexes, and how they are structured

Course Content

VSAM Basics

What is VSAM?
VSAM Features
Extended Format VSAM
Types of VSAM Data sets
Control Intervals and Control Areas
Key Sequenced Data Set (KSDS)
Key and Alternate Indexes
KSDS Processing