In 1979, Kane Kramer invented a portable digital music player. He sought patents in numerous countries, including the United States where he was granted US Patent No. 4,667,088.
The Kramer portable digital music player used memory cards, the size of a standard credit card, which were each capable of holding 3.5 minutes of music (i.e. one song). A record shop could store blank cards and load those cards on-demand from a digital music data store in the music shop at the time of sale.
A media outlet asserts that Kramer was the “inventor behind the iPod.” That statement probably goes too far in characterizing a reference that Apple made to Kramer’s patent and invention as prior art in a patent lawsuit.
Regardless, Kramer’s device was an early portable digital …