An interactive videodisk is a computer-assisted instruction technology or CAI technology that uses a computer in order to give a user access to up to two hours of video material that is stored on a videodisk. Videodisks are a precursor to the much more well-known CD-ROMs, and are read-only optical storage media, much like CDs are. Videodisks, however, are designed specifically to store and randomly access and retrieve images, stills, and continuous video.