The BACKUP operand can be used to control how often a file is to be saved. In a save run, all files with a catalog BACKUP entry less than or equal to the specification in the BACKUP operand in the SAVE statement are saved.
Example
The system support uses BACKUP=A for day-to-day saving, BACKUP=B for weekly saving and BACKUP=C for monthly saving. The user must then enter BACKUP-CLASS=A in the /MODIFY-FILE-ATTRIBUTES command for daily saving, BACKUP-CLASS=B for weekly saving, etc.
The default value for the BACKUP operand is D. If you want to exclude files from a backup with SAVE, you are recommended to assign these files BACKUP-CLASS E and only to use the values A through D for the BACKUP operand.
An exception here is formed by directory files with the BACKUP entry E: When DIRSAVE=YES is specified for an EXPORT or SAVE run and a save takes place with BACKUP=D, the directory file is saved nevertheless.