CA Dynam for VSE User Guide

Controlling Generation Data Sets
Absolute Generation Numbers
Absolute generation numbers are internal numbers recorded in the CA Dynam
Catalog for each version. To access a version by its absolute generation
number, include that number as an option in the file ID field of the DLBL
statement. For example, to access version with an absolute version number of
3, specify:
// DLBL FILE,'DISK.FILE(G=3)'
Relative Generation Numbers
The relative generation number refers to a file as it relates to the most current
version, which is designated as G-0. To request a version by its relative
generation number, include that number as an option in the file ID field of the
DLBL statement. The option code for the relative generation number ranges
from G-0 to G-98:
G-0 Requests that the current generation be accessed
G-98 Asks for the file created 99 generations ago (if it still exists)
If you request the relative version G-2 (2 generations older than the current
one), you will access the Grandfather of the latest version. Specify this option
as follows:
// DLBL FILE,'DISK.FILE(G-2)'
The following examples show the ways of using the generation data set option
to access the same file version. Assuming that six versions of the file exist,
you can access the most current version by specifying the following:
Generational Number Absolute Generation Number Relative Generation Number
// DLBL
DTF,'PAY.MASTER(G#6)'
// DLBL DTF,'PAY.MASTER(G=6)' // DLBL DTF,'PAY.MASTER(G-0)'
Chapter 4: Disk File Management 4–23