Introduction

At the heart of every operating system lies the ability to store, manage, and retrieve data—because data is what makes software useful. In the mainframe world, we don’t call them files we call them data sets.

Option 3 on the ISPF Main Menu provides a wide range of functions for library, dataset, and catalog. It contains panels to perform various operations related to file management and most commonly used by application developers. They includes

• Allocate a dataset using option 3.2
• View edit browse dataset using 3.4
• Compare two PS file using option 3.13
  • Mark differences in the files
  • Use different “Listing Type” options. (e.g. Delta, Long)
• Using option 3.3 copy one dataset to other dataset
• Search multiple strings in a dataset using option 3.14

We have split the exercise in multiple documents.

These first exercises will help application developers practice basic data set operations using ISPF panels. You'll learn how to allocate, rename, and delete data sets—common tasks when working on the mainframe.

note

Replace SHRDVXX with your assigned user id wherever applicable.

Exercise : Dataset allocations - Naming Convention

• Allocate Dataset with following name with High level qualifier as your User ID (SHRDVXX)
  • Name Within quotes
    • Second qualifier/segment name to be longer than 8 character.
    • Each qualifier/segment to be max 1 character up to total dataset length less than 44.
    • More than 44 characters in length.
    • Qualifier/Segment begins with Numeric value or any other special character than (#,@ and $).
    • Try Special character like (- , _ , +, /, *, %, !, ~) and note which are valid or invalid in any position other than the first character of qualifier.
  • Name Without quotes.
    • 44 character in length.
    • More than 44 characters in length.

Exercise : Dataset allocations - TSO Profile and prefix

• Modifying prefix with TSO Profile and try allocating dataset.
  • Try to change the prefix using TSO PROFILE PREFIX command and try to allocate a dataset with and without adding the dataset name within quotes.
    • Ex: Dataset with quote 'SHRDVXX.ABC.DEF'
    • Ex: Dataset without quote ABC.DEF
  • Try to give PREFIX as SHRDVXX.AA and retry the same.

Exercise : Dataset allocations - Dataset properties

Note: Not all combinations are valid—this is part of the learning!

Part 1: Space Allocation

1. Allocate a new sequential data set using the ISPF "Allocate New Data Set" panel.
2. Try different combinations of Space Units, Primary Quantity, and Secondary Quantity:
   • Use CYLS (Cylinders) and TRKS (Tracks) as units.
   • Try varying primary and secondary space values (e.g., 5/2, 10/5, 1/1).
3. After allocation, press I (for Information) next to the data set name in the Data Set List panel to check:
   • Current Allocation
   • Current Utilization
4. Observe how space settings impact the actual usage and free space.

Part 2: DCB Parameter Variations

Use the following DCB combinations while allocating new data sets. For each, observe if the allocation is successful and note any warnings or errors:

RECFM	LRECL	BLKSIZE
F	80	800
F	80	80
F	32761	32761
F	32760	32760
FB	80	800
FB	80	80
FB	32761	32761
FB	32760	32760

• 🔍 What to look for:
  • Are you getting a warning about block size?
  • Does the system automatically adjust any value?
  • Which combinations fail or work without issues?

Part 3: Data Set Name Type & Directory Blocks

• Try allocating the following types of data sets:
  • Sequential (non-partitioned)
  • Partitioned (PDS) with and without specifying anything in Data Set Name Type.
• For each partitioned type, set different values for Directory Blocks:
  • Try values like 5, 10, 50
  • Try value 0 for directory block and add PDS in data set name time
  • Check the effect in the Information screen after allocation

Exercise : Rename and delete PS files

• Rename a data set to a new name that doesn't already exist.
• Try renaming a data set to a name that already exists (to see what happens).
• Delete a data set that already exists.