Optical disk media para.oeters are examined with respect to recording capability, dimensional constraints, and the necessary interface with recording equipment. The parameters discussed include recording properties such as Media sensitivity and recorded signal quality. The mechanical dimensional tolerances required to proimote media. interchange ability, and to permit effective optical tracking and focus control are also discussed. The stated values reflect the current understanding of requirewents for automated, optical disk systems, and the reasons for the selection of these values are presented. A recording equipment of primary interest is the multidisk jukebox, with its requirements for disk protection and automated. deployment. Consequently, emphasis is given to the interface of disk media with the optical and mechanical subsystems of random-access, multiple-disk equipment.