Consumer electronics: Video disks: Three choices: Three incompatible approaches to video recording for playback are compared

A new era in information storage and playback is beginning as video disks and players find their way increasingly into consumers' homes. At about $20, a plastic, mass-produced video disk with a 30-centimeter diameter can carry the equivalent of more than 1010 bits. To store that kind of information for computers, several typical high-density disk-storage systems, or disk packs, would be needed, each using 19 magnetic-disk surfaces and costing about $1000. Furthermore, unlike computer storage systems, consumer video disks do not require elaborate temperature, humidity, and dust controls during operation; they are shipped and handled without special care, like thousands of other products. Of course, the information on a video disk can only be played back. A user cannot record on the disk — at least not yet.