DD-1

The DD-1 sat outside the standard music Discman story as Sony's first serious consumer push into portable optical data instead of audio. Built around 8 cm discs loaded with dictionaries, books, and reference material, it included a compact screen, keyboard, and dedicated software titles that made it behave closer to an early e-book reader or handheld information device than a music player.

Compact disc had interested Sony as a broader medium for years, more than as a way to play albums. The DD-1 belongs to that parallel track, where optical media was being tested as a portable reference format long before later digital reading devices became common. It is a side branch now, but a revealing one.