Philips CD-i console, also known as Green Book, which was co-developed by Philips and Sony. In addition to games, educational and multimedia reference titles were produced, such as interactive encyclopedias and museum tours, which were popular before public Internet access was widespread. The CD-i was also one of the earliest game systems to implement Internet features, including subscriptions, web browsing, downloading, e-mail, and online play. This was facilitated by the use of an additional hardware modem and "CD-Online" disc (renamed Web-i in the US), which Philips initially released in Britain in 1995 for $150 US. Development of the CD-i format began in
CD-R the cost of typical recorders was down to $10,000–12,000, and in September 1995, Hewlett-Packard introduced its model 4020i manufactured by Philips, which, at $995, was the first recorder to cost less than $1000. The dye materials developed by Taiyo Yuden made it possible for CD-R discs to be compatible with Audio CD and CD-ROM discs. Initially, in the United States, there was a market separation between "music" CD-Rs and "data" CD-Rs, the former being several times more expensive than the latter due to industry copyright arrangements with the RIAA. Physically, there is no difference between the discs save for the