I was looking through some old software and came across an interesting disc I had never seen before. It is simply labeled Master Disc (CD-R 71PS) and has a Playstation logo on the front. On the disc itself it has the Playstation logo and a list with Title, Licensee Name, Ref. No, Rec. Date, Ver. No, and Disc Type (PS or PS2). I popped the disk into a PC to see what it had on it, and it had Knoppix installed on it...but nothing written on and the inserts are still in the case. Says That's CD-R on the side and has some cleaning tips and other text on the rear. Was wondering if these are rare or what they are exactly? Found some information online but not a whole bunch. Any info appreciated, I just thought it was cool, being a PS fan.