Query of a Data Set Generation

The Inquire/Update screen of Control-M/Tape can be used to display information about a specific generation of a data set or data sets.

To display a specific generation, indicate the generation number in parentheses after the data set name in the DSNAME field of the Inquiry/Update entry panel. For example, DS1.LOG(-1).

The generation specified with the data set name can be a number from 0 to -99, where 0 is the current (newest) version of the data set, -1 is the second newest version of the data set, and so on. For example, PAYROLL.DB(-2) refers to the third most recent version of the data set.

If a data set name mask is specified in the DSNAME field, Control-M/Tape searches for the specified generation of all of the data sets that match the specified mask.

The following logic is used to determine the requested generation of each data set:

1. Data sets that match the mask are sorted according to data set name, creation date and creation time.
2. Each group of data sets with the same name (excluding the GxxxxVyy suffix) is considered a group of generations of the same data set.
3. The most recent version of each data set is considered generation 0, the next most recent generation is -1, and so on. The requested generation for each data set is displayed.

Note: The above logic applies to all data sets in the Control-M/Tape Media Database, whether or not they are GDG data sets.

Example

If DB.LOG.*(-1) is specified in the DSNAME field, and the following data sets are defined in the Media Database:

DB.LOG.Y2000.BACKUP                               31/03/00

DB.LOG.Y2000.BACKUP                               31/07/00

DB.LOG.Y2000.BACKUP                               31/12/00

DB.LOG.Y2001.BACKUP                               31/01/01

DB.LOG.Y2001.BACKUP                               31/03/01

The following data sets are displayed:

DB.LOG.Y2000.BACKUP                               31/07/00

DB.LOG.Y2001.BACKUP                               31/01/01

Note that each data set displayed is the second most recent generation of its group.