The Sony Data Discman was an e-book reader launched in Japan in 1990 with the Data Discman DD-1, reaching the US at the end of 1991, and the UK market at the end of 1992.
The discs themselves are essentially mini CD-ROMs enclosed in a caddy. CD-ROM drives were a rarity in home computers at this time, though multimedia PCs became more commonplace a few years later. The software on the discs is written using the Sony Electronic Book Authoring System (SEBAS) and is only readable by the Sony Data Discman players. Some models could play mini Compact Disc singles without a caddy.
There were different types of disc throughout the life of the system, such as EBG which can contain text and images, and EBXA which can contain text, images, and audio.
The titles available tended to be reference books such as dictionaries, encyclopaedias and directories, though there were some discs that contained classic works of literature. Searches could be done using the QWERTY keyboard, and navigation was by function keys, a cursor pad or yes/no keys.
The screen was small, low resolution, and monochrome only (no grayscale). It was possible to output the video to a TV but this defeated the object of having a portable player, and it would still only display 10 lines of text at a time.
Sales in the US and Europe were poor and it stopped being marketed in those areas around 1993, though it sold better in Japan and new models were released, along with more book titles. There were even some later models introduced in 2000 that could display colour, and to make use of the colour feature, discs using a newer S-EBXA format were also released. The final model, the DD-S35, was released in Japan in 2000 and came with a much improved grayscale display and battery life.