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A Method of Simulating and Calculating the Effect of Record Management Requests on a VSAM Data Set

IP.com Disclosure Number: IPCOM000243110D
Publication Date: 2015-Sep-15
Document File: 4 page(s) / 44K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to simulate Virtual Storage Access Method (VSAM) activities in order to answer questions that are beyond the scope of simple experimentation. This simulator emulates the effect of various record-management requests or sets of requests against VSAM data sets, and then provides the results to the user as a list of statistics along with a graphical representation.

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A Method of Simulating and Calculating the Effect of Record Management Requests on a VSAM Data Set

Currently, there is no easy way to obtain detailed information or statistics about how different Virtual Storage Access Method (VSAM) definitions affect the VSAM structure and performance. For example, answering the question, "How many sequential inserts does the user need to perform before getting a CI split," cannot be answered quickly through experimentation. The user must repeatedly re-run the same job and check the LISTCAT output until finding the desired results This can be an intensive process, both in terms of time and computing resources. Additionally, users may not always be able to simply experiment due to the limitations of the mainframe systems or access to the systems.

The novel contribution is a method to simulate VSAM activities in order to answer questions that are beyond the scope of simple experimentation. This simulator emulates the effect of various record-management requests or sets of requests against VSAM data sets, and then provides the results to the user as a list of statistics along with a graphical representation. In addition, this method allows the interruption of the simulation at specific key points. For example, it can stop running ERASE requests when the first CA Reclaim occurs. This allows users to simulate various types of programs and understand the effect it has on the underlying VSAM data sets, without actually allocating those resources.

At the highest level, this method operates in a four-step process (each of these steps is described below):


1. Gather input information
2.

Build simulation script
3. Simulate VSAM activities
4. Report statistics

This overall process is achieved using two entities. The first is the Simulation Control , which is responsible for handling

the inputs, executing the simulation, and displaying the outputs (Steps 1 and 3). The second entity is the VSAM Simulator itself. Using the data set parameters and a list of requests to be performed against it, the VSAM Simulator performs the simulating (Step 2).

Step 1 - Gather Input Information

At this stage, the Simulation Control prompts the user for input information in two categories:

1. Category 1 - VSAM Data Set Information


A. Control Interval Size (Data and Index)
B. Free space (Data and Index)

1


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C. Record sizes, specified as a constant or Minimum and Maximum. (If Min=Max, then size is assumed to be constant)


D. Allocation size parameters, Primary and Secondary


E. Volume characteristics for simulated volume (Bytes per Track, Tracks per Cylinder, Cylinders per Volume).

      Includes presets such as 3390-3 = (56664, 15, 3339) respectively.
2. Category 2 - Simulation Program and Control

A. What type of simulation back-end to use, options are:
i. Real -- the simulation parameters are passed to a z/OS back-end system and run there
ii.Virtual -- the simulation is run within a virtual VSAM box on the local computer

B. What typ...