Mark Fleiscmann writes: Does the world need another optical disc format in this download-oriented era? Sony and Panasonic think so, though they’re positioning the Archival Disc for professional use in the movie industry and in cloud-based data centers. The format holds 300 gigabytes on a double-sided disc with three layers per side. It is said to be resistant to dust, shock, and extreme temperatures compared with hard disks, the data-storage workhorses of today. Initial pro-level hardware is predicted to arrive in summer 2015. No plans have been announced to turn the Archival Disc into a consumer-level format.