After applying Rel 12.6 RO63948, when an End-Of-Volume (EOV) is read before an End-Of-File (EOF) and no secondary volume was specified (or cataloged) the next-volume from CA 1 is supplied to the operating system and rest of the data from the file is read. However, some applications may only want to read a portion of the data and do not want to read the complete file. How can you make it operate the way it did prior to z/OS 1.13 with RO63948 applied?
CA1 12.6 and 14.0
RO63948 now resolves the conflict by filling in the next volume to be mounted via the Label Anomaly Exit until the end of the volume chain within the TMC is reached. When the exit is invoked, the IBM message IEC716I TAPE MULTIVOLUME LIST CORRECTED will be issued and the job will continue reading until the next EOV condition arises. This will then be repeated until an EOF condition is reached or the application stops reading the file. This forces all the rest of the chain to be read to retrieve the data.
If there is a user application that is only expecting the one volume, the work around is to add a OPTCD=B to the DD statement pointing to the volume. That basically says to accept EOV as EOF.