Memorex Visual Information System Guide
Attribution: Logg Tandy, Public domain, via Wikimedia Commons
AKA Tandy VIS
Serial is not necessarily the ID that is printed on the disc label, but the catalog number (e.g. 25-6###) that may be printed on the box.
Example: The Adventures of Victor Vector & Yondo: Adventure No. 1: The Vampire's Coffin has a Serial value of "25-6115" even though "VVY1-VIS1" is printed on the disc label.