High Capacity Optical Data Storage and Retrieval Systems

Abstract

Recording of digital data on photographic film is the practical solution to a broad spectrum of computer memory and data storage and retrieval requirements. Mass memory systems with bulk storage capacities between 1011 and 1013 bits with multi-second access times are currently being built. Development effort is also continuing in the specialized area of ultra-high speed transfer of data into and out of large intermediate bulk stores. Systems currently being produced by Harris Electronic Systems Division take advantage of holographic principals: (1) a natural distributive encoding by recording the information over the entire hologram rather than at discrete points, thereby reducing susceptibility to dust, scratches and recording media imperfections, (2) reconstruction of the data into parallel non-skewed channels, and (3) insensitivity of the recording medium placement relative to the detector array, greatly reducing mechanical tolerances necessary for rapid access and ultra-high speed data transfers. The purpose of this paper is to present a synopsis of the current status of each of two storage and retrieval systems under development for the U. S. Air Force. The first system we describe (HRMR Microfilm Mass Memory System) uses photographic film in the form of microfiche to provide a mass storage capability with automatic, computer-controlled, random access to stored records. The second system we consider (Wideband Holographic Recorder) uses multichannel recording on roll film for storage and retrieval of large unit records at hundreds of megabits per second.