These discs take advantage of unused subcode space on audio discs to add computer graphics that are slowly assembled and displayed when the disc is played. El Torito is the bootable CD specification developed by Stan Merkin and Curtis Stevens. Enhanced CD is an umbrella term that covers a number of alternative ways to store multimedia data on audio CDs. Mixed Mode CDs contain a data track followed by one or more audio tracks.
Hybrid discs are readable in native form on more than one operating system.
HFS discs are discs using Apple's Hierarchical File Structure. For more information on these CD-ROM variants, click on the links above.