Database Management Using Optical Associative Memory

摘要

A concept was developed for an optical based associative memory system thataccepts a query request from a user, searches the disk for the location of the information and ensures maximum efficiency in data recovery. The system was divided into three parts; user interface and controls, optical correlation, and post processing and analysis. Concepts were developed for the user interface and control subsystem and for the post processing and analysis subsystem. A breadboard was developed to test the correlation subsystem concepts. Two basic concepts were tested; both were successful to some level. The first is an all optical approach in which the data correlation is performed by a space integrating optical correlator. The second is a hybrid optoelectronic approach in which the data is read back in parallel and fed into an electronic correlator. The optical correlator is a space integrating image plane architecture. The output of the correlation is the number of bits in the query that match bits recorded in that section of the data. The nature of ASCII coding resulted in excessive background fluctuations during readout. The implementation of a custom code and bias subtraction processing reduced the background fluctuations making it possible to set a threshold that locates the correlations. However, any threshold that ensures 100% detection will generate a high false correlation rate.