The STORAGE(00,NONE,00,0K)/ is just a text string sent to the program in a defined way. The text string has meaning only to the program. The program, and only the program, translates the contents of the text string and converts it to values that are important to the program.
Most Cobol, PL/I and C programs are linked with a run time subroutine package called Language Environment, often abbreviated as LE. LE gets a look at the parameter text before the actual program sees it. The / character separates the parameter text your program sees from the parameter text LE uses. What I think we have here is LE looks at STORAGE(00,NONE,00,0K), and passes a null string to your program. A manual titled Language Environment Customization for your z/OS release should tell you how LE interprets STORAGE(00,NONE,00,0K). Good luck.