Difference between delete , purge erase force:
Delete: This command is used to delete the VSAM, GDG and PS Files.
Purge: This will delete the Generation of a GDG , even though it's retention period is not completed.
Force: This will delete GDG Index, all generations and Modal of the GDG even though it's retention period is not completed.
Erase : Normally this command is used with VSAM data sets. This will ensure that after the deletion of the data set , no one can read it from the DASD. using the utility like IEHDASDR . This Erase command will replace BINARY zero with Dataset. (It is prefered for sensitive datasets)