Opto-Electronic Associative Memories Based on A Motionless-Head Parallel Readout Optical Disk.

Abstract : Current secondary storage systems have low transfer rates relative to CPU processor needs. For memory intensive applications, such as data base machines with large on-line storage, this creates a performance bottleneck since the I/O subsystem forces the CPU to wait for data. Optical disks, which are now a commercially available medium, offer high storage densities (100 Mbits per square centimeter), low cost ($0.1/Mbyte), robustness (no head crash) and, as for other optical memories, the possibility for parallel readout. Still, although high storage densities are possible with optical disk systems, high throughput has not yet been achieved. One solution to processing bottleneck is the Motionless-head Parallel Readout Optical Disk System. This is a hybrid system combining holographic and imaging optical techniques. The underlying principle is that all mechanical motions of the head above the disk surface have been eliminated for addressing focusing and tracking. The Motionless head Parallel Readout system is designed to generate 2-D binary bit plane outputs, while the recording of the data on the disk remains sequential and can be done using a commercially available drive.