I am looking at the backup set interface which shows the dates and location of data (Tape, Disk or both)
I have a Full backupset on both Disk and Tape on 4/22/13
I also have another Full backup on Tape on 4/27/13
How come when I select the Full backup set to be deleted from 4/22/13, I am prompted that additional backup sets that depend on this are from dates after 4/27/13. (I would think that other backup sets might only depend on the nearest Full...which in this case would be 4/27/13. So why can't I delete 4/22/13 without additional prompts?)
Take a look at the incremental/differential sets that are dependant on the full set that was taken on 04/22/2013 and verify that they have reached the end of their protection period "This is more than likely the reason that you are unable to delete the previous full". If were talking about your disk based backups B.E.'s DLM should go in and prune the backup sets as they reach their expiration dates.
Mostly it would be the case where in you have the backup job spanned across multipe tape or BkF files. Are you trying to reclain space on Disk or on Tape. As infromation on the tape is written seqencially you cannot delete a specific date backup set. You can get a better Idea of what data the media have by going to the restore and View it by media .