Report Number: CSL-TR-87-338
Institution: Stanford University, Computer Systems Laboratory
Title: Sparse, distributed memory prototpe: principles of operation
Author: Flynn, Michael J.
Author: Kanerva, Pentti
Author: Ahanin, Bahram
Author: Flaherty, Paul A.
Author: Hickey, Philip
Author: Bhadkamkar, Neal A.
Date: February 1988
Abstract: Sparse distributed memory is a generalized random-access
memory (RAM) for long (e.g., 1,000 bit) binary words. Such
words can be written into and read from the memory, and they
can also be used to address the memory. The main attribute of
the memory is sensitivity to similarity, meaning that a word
can be read back not only by giving the original write
address but also by giving one close to it as measured by the
Hamming distance between addresses.
Large memories of this kind are expected to have wide use in
speech and scene analysis, in signal detection and
verification, and in adaptive control of automated
equipment---in general, in dealing with real-world
information in real time.
The memory can be realized as a simple, massively parallel
computer. Digital technology has reached a point where
building large memories is becoming practical. This research
project is aimed at resolving major design issues that have
to be faced in building the memories. This report describes
the design of a prototype memory with 256-bit addresses and
from 8K to 128K locations for 256-bit words. A key aspect of
the design is extensive use of dynamic RAM and other standard