Detail line descriptions

Data set
This shows the name of a data set that was open at some point during the observation sesion.
DDNAME
This line shows a DDNAME corresponding to the data set name. There could be multiple entries under a data set if the data set was open more than once (concurrently or serially) with different DDNAMEs. If the same DDNAME is open (and closed) multiple times for the data set, it is suffixed with an instance number to indicate this.