Optically Read and Servoed Direct Access Storage Device
Original Publication Date: 1980-Aug-01
Included in the Prior Art Database: 2005-Feb-13
The disk surface used by this apparatus is one in which a "normal" electromechanical write servo system is in place. The addition of the optically read and servoed data retrieval device, as shown in Fig. 1, reduces the average access time to near zero relative to the latency, and because the time to "seek" from one track to another isn't a function of the distance between the tracks, formatting the data in such a way as to make the latency not affect data acquisition time is simple. This is a read-only device, and would find use in fixed head replacement, yielding typically up to 50 times the "fixed head" capacity. A disk 17 has triangular portions 17a thereon which have a different light reflectivity than the surrounding areas of the disk.