CA Dynam for VSE User Guide

Controlling Generation Data Sets
Generation numbers defined by G#nn are put in the last four bytes of the file
ID within the disk's VTOC. So, do not use positions 41—44 of the file ID when
defining the data set to the Catalog. The generation number, which can range
from 1—99 (with full wraparound), is entered in the following format:
G#nn
where nn is the generation number
Example,
'PAY.MASTER.FILE.........................G#15'
CA Dynam 7.1 data sets can also be defined by appending .G#nnnnn to the
end of the data set name by defining the data set with GDGLONG=YES. An
input version from either format is specified by G#nn within the data set name
on the DLBL.
When CA Dynam/D is called by the creation program to close the file, it
records this new generation number as the current one. The current
generation number of a file can be identified from the following:
• You can use the DYNCAT utility program to display the current generation
number and the maximum number of generations. You can also ALTER the
next generation number to be created.
• You can use the system messages to display current generation
information.
• You can use the DYNVTOC utility program to display the current
generation number.
• You can use CUI File Management to display the current generation
number.
Changing Generation Numbers
If it is necessary to change the current generation number to a lower value,
the VTOC entries for the already existing files above this number should be
removed from the DASD devices upon which they reside. (For more
information about the DYNUTIL DELETE command, see Supporting Disk File
Management.)
In addition, remove their associated version records from the Catalog before
the generation ID is updated with NEXTGEN.
Chapter 4: Disk File Management 4–21