What is a walkman?

1979 Sony developed the world's first Walkman portable tape player, marking the birth of the concept of portable music, and the word Walkman became synonymous with portable music players. It has been more than 20 years since the development of audio-visual theory, during which new music standards and varieties have emerged continuously. At present, there are four popular audio-visual players: Walkman, Walkman, MD and MP3. The walkman generally refers to the tape walkman with analog recording in this paper, and the last three are the digital walkman that I mainly introduce today.