The OS/VS COBOL and VS COBOL II examples each provide the same function. They show a simple case of the use of the DFHMFSET entry point with the Page List that is returned for the SET option on BMS SEND commands.
They each do a SEND MAP command using the SET option that returns the address of a Page List containing the address of the datastream in the first entry. Note that the second entry of the Page List contains the end-of-list marker. The examples convert the Page List entry to a "real" TIOA address for the built datastream, establish the addressability for the datastream, and actually send it to the terminal using a SEND TEXT MAPPED command.
Note that the PIC X(9999) for PAGE-DSC-AREA and the value of 5 in the OCCURS clause for PAGE-LIST-ENTRY are not in themselves significant; they are just the values used in this example.