To define the type of access you want for the data set, specify one of the following:

• OLD - gives you exclusive access, such that no other user can access the data set until you are finished using it. You generally request OLD access when you want to modify the data set.
• SHR - gives you non-exclusive access, such that other users can access the data set while you are using it. You generally request SHR access when you want to read data, not modify it.
• MOD - gives you exclusive access to add data to the end of a sequential data set. To add information to a member of a PDS, rewrite the member with the additional records added.

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