MERGE, Output File Qualifiers, /SEQUENTIAL, Full Description
*Conan The Librarian
If the organization of the output file is to be different from that of the input files, you must specify the new organization. If you do not specify file organization, the default for record and tag sorts is the organization of the first input file. If you do not specify file organization, the default organization for address and index sorts is sequential. Use the /SEQUENTIAL qualifier when the default is not sequential file organization and you want an output file with sequential file format.