Large Archival Mass Memory System Using Optical Diskettes

Abstract

The transition of digital optical mass storage technologies from the laboratory to an integrated deliverable system is a challenge whose time has come. Harris Corporation has accepted the challenge and will deliver a 1013 bit Archival Mass Memory (AMM) System. AMM provides: variable data ingest rates up to 50 Mbits/sec accommodating sources as diverse as telephone links, computer links, and satellite downlinks; Reed-Solomon error detection and correction (EDAC) coding to preserve better than a 10 -9 bit error rate (BER) for up to 10 years of operation without rerecording; real time optical spot recording of 109 user bits on each 148 X 148 mm diskette; storage and automatic on-line retrieval of data from 1024 diskettes housed in each storage and retrieval unit; less than 15 second access time to any record in the archive; simultaneous data recording and readout; forward file management for rapid user-oriented access down to the byte level; simultaneous access to multiple modular storage and retrieval units; and variable output rates up to 50 Mbits/second direct or interleaved for multiple variable rate users tied to the fiber-optic distribution bus. This paper outlines the system design and performance including the complex electro-optic technologies employed to provide high-speed high-density optical spot recording and readout.