Multipart memory apparatus with error detection

• US 5,142,540 A
• Filed: 03/13/1990
• Issued: 08/25/1992
• Est. Priority Date: 03/13/1990
• Status: Expired due to Term

• Current Assignee: Glasser, Lance A.
• Original Assignee: Glasser, Lance A.
• Inventors: Glasser, Lance A.
• Primary Examiner(s): Atkinson, Charles E.
• Application Number:
  US07/492,633
• Time in Patent Office: 896 Days
• Field of Search: 371/40.1, 371/2.2, 365/189.04, 365/230.05
• US Class Current: 714/772
• CPC Class Codes: G06F 11/1008 in individual solid state devices G06F11/1004 takes precedence
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G11C 29/88 with partially good memories

Abstract

A memory apparatus for storage and retrieval of digital data is disclosed, including a controller and a memory element having an array of memory cells, each cell having fewer ports than are provided by the memory system. The memory cells are adapted for storing digital data words, each word being a set of bits or symbols. The memory array is partitioned into a plurality of bins for storing words, the individual bits of each word being distributed in a selected addressing sequence among a plurality of selected bins in the memory array, such that bin reading conflicts generate a number of errors less than or equal to a numerical error limit K, where K is less than the number of bits in a word. The data words can be manipulated so as to produce error-free results.

Claims

1. A memory apparatus for storing and providing retrieval of multiple-bit digital data words, the apparatus comprising

memory array means for selectively storing the data words, said memory array means being partitioned into a set of bins for storing the words, each said bin including an array of memory cells capable of storing at least one bit, each memory cell having a number of memory cell ports,

external data port means, in communication with the memory array means, for receiving at least one of (i) words to be stored in the memory array means or (ii) words to be retrieved from the memory array means, said external data port means having a number of external ports, the number of external ports being greater than the number of memory cell ports of a single memory cell,

control means, in communication with said memory array means, for receiving first external signals representative of requests, asserted by an external port, to execute at least one of (i) storing a word in the memory array means or (ii) retrieving a word stored in the memory array means,

address decoding means, in communication with said memory array means and said control means, for receiving second external signals representative of external memory address values designating words to be either stored in or retrieved from said memory array means, and converting said second external signals into internal bin addresses designating a plurality of selected bins in which bits of a word are to be either stored or retrieved, said address decoding means including

bin address calculation means, responsive to bit-position values of the bits of each word to be either stored or retrieved, for calculating said bin addresses in accordance with a predetermined bit distribution pattern, to distribute the bits into selected bins, such that requests to retrieve a given data word result in a limited number of bin reading conflicts, the number of bin reading conflicts associated with each word being less than the number of bits in each word, and

error correction means, in communication with the memory array means, for receiving words retrieved from the memory array means and correcting errors in each word resulting from bin reading conflicts, to provide substantially error-free output words.

2. Apparatus according to claim 1, wherein the number of external ports is two, and the number of memory cell ports in each memory cell is one.

3. Apparatus according to claim 1, further comprising data channel means, connected to the memory array means, for connecting the memory array means to a remote digital processor.

4. Apparatus according to claim 1, wherein said control means includes priority control means for assigning a priority value to each request to either (i) store a word or (ii) retrieve a word, wherein a request to store a word is assigned a higher priority value than a request to retrieve a word, so that fewer conflict errors arise from execution of requests to store data words than from execution of requests to retrieve data words.

5. Apparatus according to claim 1, further comprising conflict detection means, in communication with said memory array means and with said error correction means, for detecting conflicts, in response to said requests asserted by said external ports, and for transmitting to said error correction means a conflict indicator signal indicating which bits in a given word are involved in a detected conflict.

6. Apparatus according to claim 5, further comprising parity bit means for storing in said memory array means, in association with each word, at least one parity bit having a selected value, and

wherein said error correction means contains parity checking means, responsive to said conflict indicator signal, for testing the value of said at least one parity bit in each word having bits involved in a detected conflict, and for correcting the value of each bit involved in a detected conflict in response to a parity bit value other than the selected parity bit value.

7. Apparatus according to claim 1, wherein said error correction means includes means for correcting errors arising from sources other than conflicts.

8. Apparatus according to claim 1, wherein

said address decoding means includes simultaneous-read means for providing accurate retrieval of a given word stored in said memory array means to a plurality of external ports simultaneously asserting a request to retrieve the same given word, said simultaneous-read means comprising

address equality testing means, responsive to said external memory address values, for determining whether more than one external port is simultaneously asserting a request to retrieve the same given word, and for generating an address-equal signal when more than one external port is simultaneously asserting a request to retrieve the same given word,

access enable means, for enabling one external port to retrieve the given word, and

retrieved-word distribution means, responsive to the address-equal signal, for distributing the retrieved-word to all ports asserting a simultaneous request to retrieve a given word.

9. Apparatus according to claim 1, wherein said memory array means is structured in a pipelined configuration.

10. Apparatus according to claim 1, wherein said address decoding means includes means for processing multiple simultaneous requests to store words in a plurality of bins.

11. Apparatus according to claim 1, further comprising at least one arithmetic logic means, in communication with said memory array means, for executing selected arithmetic operations on bits stored in said memory array means.