CA Dynam for VSE User Guide

Using CA Dynam/T
Establish the retention characteristics with the DYNCAT DEFINE command. You
can alter them with the DYNCAT ALTER command.
Before the system permits a generation to be scratched, the generation must
be eligible for scratch under all the retention schemes associated with the data
set.
Data Set Retention Options
You may retain a data set for a specific number of the following:
• Days, or until a specific expiration date has been reached (date retention)
• Generations
• AS-OF-DATE cycles (also known as PERIOD ENDING DATE cycles)
• Days since last access
Date Retention
Date retention is based upon an expiration date calculated from the creation
date and the number of retention days specified either in the Catalog or on the
TLBL statement used in the creation of the generation.
If retention days are specified in both the Catalog and the TLBL, the larger
number is used. This provides the longest possible retention. When the
expiration date is reached, the version is eligible for scratch.
Generation Retention
Generation retention is based on the number of cycles specified in the Catalog.
For example, if four cycles have been created but the Catalog specifies only
three, the fourth (the oldest) becomes eligible for scratch.
AS-OF-DATE Retention
CA Dynam/T is the only tape management system that provides AS-OF-DATE
retention. It is based on the number of AS-OF-DATE cycles specified in the
Catalog.
The AS-OF-DATE is a characteristic of each version of a data set. When a
version is created for a data set with AS-OF-DATE control, the AS-OF-DATE for
that version is established in any one of the following ways:
• Permanently with the DYNCAT DEFINE or ALTER commands
• According to the partition communications region date, as set by // DATE
mm/dd/yy, if no permanent AS-OF-DATE characteristic has been set
Chapter 2: Maintaining Tape Files 2–9