The SNES CD add on was actually called the "Playstation"
To make a long story short Nintendo didn't like Sony having any rights with the CD based software, which they would if Sony made the drive, so Ninty gave Sony the big middle finger.
So Sony in turn gave Nintendo and even bigger middle finger and developed their own hardware. They also kept the name "Playstation" to further say "fuck you" to Nintendo and their arrogant ways. Ever since Sony has been gunning for the "big N". While Sony was sucessful in crushing Nintendo ever since in the console race, there remained one last bastion of strength for Nintendo, the unchallenged multi billion dollar handheld market. Enter PSP.... To be continued.