The Diamond Rio was one of the earliest portable digital media devices - released in late 1998 it sold extremely well and put the MP3 firmly on the map. So much so that some members of the record industry attempted to sue Diamond claiming the PMP300 encouraged music piracy.
The Diamond Rio player was one of the products that Apple executives examined while they considered a foray into the digital media player market. Although they were quick to fault its lack of user friendliness and capacity (Jobs said it "truly sucked") - an echo of its wheel shaped control panel can be seen in the iPod classic of 2001.
Campbell Bickerstaff, 2012