CompuServe Messages

Rich, I understand what you're saying about the CD-ROM connection between various implementations, and agree that it could be looked at that way sometimes. However, I don't think that just using a CD-ROM drive with different *HOST* (non-drive) hardware automatically means you've made an extension or refinement of Compact Disc. Using that simple criterion, every computer with a CD drive could be considered a new CD "format". But they're obviously not. Likewise, different storage formats on the disc (dir systems such as ISO9660 or HS… or data encoding such as GIF or Photo CD) don't make a new CD format. For example, CDTV isn't an extension of CD-ROM. It uses a normal CD-ROM (ISO9660 Mode 1 files, no XA, no multisession) setup. In other words, like most other CD-ROM based systems, it uses the drive as standard mass storage. OTOH, as you said, CD-ROM is an extension of CD-DA. It requires additional *drive* decoding hardware. Likewise, CD-I and XA further extend Compact Disc functionality by adding the requirement for ADPCM audio decoding and buffer hardware. best – kevin