Multi-port Memory Invention

In 1990 I filed a patent on a new kind of multiport memory. It exploits the fact that we store words rather than just bits in memories. By storing the words in clever ways one can tolerate collisions among accesses to the memory and still guarantee perfectly correct results. Prof. Ron Rivest of M.I.T. helped me with the concepts and we wrote a memo on it called A fast multiport memory based on single-port memory cells.

We present a new design for dual-port memories that uses single-port memory cells but guarantees fast deterministic read/write access. The basic unit of storage is the word, rather than the bit, and addressing conflicts result in bit errors that are removed by correction circuitry. The addressing scheme uses Galois field arithmetic to guarantee that the maximum number of bit errors in a word accessed is one. These errors can be corrected every time with a simple correction scheme. The scheme can be generalized to an arbitrary number of ports.