Memories: An optical disk replaces 25 mag tapes: This 30-cm disk features a long-life tellurium film upon which data is impressed by laser

Abstract

This 30-cm disk features a long-life tellurium film upon which data is impressed by laser. No processing of the optical disk is required, and a shelf life of ten years is indicated. The optical system is designed to check the recorded data instantly and to rerecord at once any part of the disk where discrepancies appear. Such a disk was developed experimentally for the Philips DRAW (Direct Read After Write) information system. The DRAW (a registered trade name) system records information serially on a 30-cm disk with 40000 tracks per side, for a total capacity of 1010 bits per side. With disk-pack and `juke-box' techniques, the storage capacity might be increased even further beyond these limits.