A data set is deallocated when you log off the system or you issue the FREE command. What happens to a data set after it is deallocated is called the disposition of the data set. You can specify the disposition of an existing data set with the following operands:

• KEEP - the system retains the data set. This is the default for existing data sets.
• DELETE - the system deletes the data set.

ALLOCATE DATASET(input.data) FILE(sysin) OLD DELETE