Robert Mcfarlane

Digital Optical Recorders At 5 Mbit/S Data Rate

Five optical disk recorder/readers were developed, each having an on-line user storage capacity of 101° user bits per disk side. The advantages of optical recording, as compared to magnetic-tape recording, are improved archival life, low cost media, and rapid random access capabilities. Recording at a 5 Mbit/s user data rate is done by laser machining of micron-sized holes in a thin tellurium alloy film allowing direct-read-after-write recording of information. Coding and error correction reduce the user error rate to 10-1°. The recorders have been interfaced to DEC PDP-11 minicomputers and for test purposes to a SEL 32/77 computer.

An Optical Disc Data Recorder

We discuss the development of an optical disc recorder with an on-line storage capacity of 1010 bits. Recording is done by laser machining of micro-sized pits in a thin tellurium film allowing direct-read-after-writing (DRAW) of the information. The recording format maps each bit of information to a recorded pit. The tellurium is deposited on a clear plastic disc configured to be self-protecting and easily handled. A major program objective was to demonstrate the feasibility of an inexpensive recorder and disc.