I want to know the answer to the following question:
What was Sega's CD add-on?
All the background I'm provided with is that "Ultimately, deals with both Sony and Philips fell through, (although a prototype console was produced by Sony) with Philips gaining the right to release a series of titles based on Nintendo franchises for its CD-i multimedia player and Sony going on to develop its own console based on its initial dealings with Nintendo (the PlayStation).". Is that enough to answer the question?