VSAM tutorial for mainframe programmers

Virtual Storage Access Method – VSAM – is a data management system introduced by IBM in the 1970s as part of the OS/VS1 and OS/VS2 operating systems.

Although there are still datasets that are best managed with the several other (non-VSAM) data management methods, VSAM is a major component of modern IBM operating systems. Since MVS 3.8 is one of those operating systems, I thought it might be useful to other Hercules’ users to set down some basic information about VSAM.

I have divided the material presented here into two main segments

  • Concepts and Facilities
  • Access Method Services

In the first segment, I will try to provide a simple description of the components of VSAM, with the goal of introducing VSAM to those who have not had practical experience with it.

I don’t want to write a textbook, as I have several of those in my own library and they can be quite dry and boring.

But, it is my perception that quite a few people are coming into the Hercules (and MVS) community who have not had any formal exposure to this type of material and I think there may be some positive benefit to my efforts.


Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.