System to Improve Miscorrection Rates in Error Control Code Through Buffering and Associated Methods

• US 20100299576A1
• Filed: 01/31/2008
• Published: 11/25/2010
• Est. Priority Date: 01/31/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Baysah, Irving G., Lastras-Montano, Luis A., Retter, Eric E., Maule, Warren E., Wright, Kenneth L., Trombley, Michael R., Trager, Barry M., Dell, Timothy J., Winograd, Shmuel
• Granted Patent: US 8,176,391 B2
• Time in Patent Office: Days
• US Class Current: 714/763
• CPC Class Codes: G06F 11/1044 with specific ECC/EDC distribution

Abstract

A system to improve miscorrection rates in error control code may include an error control decoder with a safe decoding mode that processes at least two data packets. The system may also include a buffer to receive the processed at least two data packets from the error control decoder. The error control decoder may apply a logic OR operation to the uncorrectable error signal related to the processing of the at least two data packets to produce a global uncorrectable error signal. The system may further include a recipient to receive the at least two data packets and the global uncorrectable error signal.

Claims

1. A system to improve miscorrection rates in error control code through buffering, the system comprising:

an error control decoder with a safe decoding mode that computes uncorrectable error signals by processing at least two data packets;

a buffer to receive the processed at least two data packets from said error control decoder;

said error control decoder applies a logic OR operation to the uncorrectable error signals related to the processing of the at least two data packets to produce a global uncorrectable error signal; and

a recipient to receive the at least two data packets and the global uncorrectable error signal.

2. The system of claim 1 wherein said error control decoder operating with the safe decoding mode off processes one data packet and sends the results to the recipient.

3. The system of claim 1 further comprising a memory which supplies requested data packets, and said memory is partitioned into memory ranks.

4. The system of claim 3 further comprising a table to store information about persistent failures in the memory ranks.

5. The system of claim 4 wherein said table provides information to compute a memory rank score and the safe decoding mode is enabled or disabled by said error control decoder based upon the memory rank score.

6. The system of claim 1 further comprising an agent to enable or disable the safe decoding mode.

7. The system of claim 3 wherein the data packets receive an XOR mask prior to storage in said memory and after retrieval from said memory, and the XOR mask depends on the data packet address.

8. The system of claim 3 wherein the memory ranks comprise memory chips, and if said error control decoder encounters that the at least two data packets are affected by a full memory chip error, then a global uncorrectable error signal is set if the full memory chip in error is distinct for the at least two data packets.

9. The system of claim 1 wherein said recipient comprises at least one of a processor and a cache.

10. The system of claim 1 wherein if the global uncorrectable error signal is set, then contents of said buffer are stored in a cache and identified as faulty.

11. The system of claim 1 further comprising a cache where the at least two packets processed by said error control decoder corresponds to a line of the cache.

12. A method to improve miscorrection rates in error control code through buffering, the method comprising:

processing at least two data packets and applying a logic OR operation to the uncorrectable error signal related to the processing of the at least two data packets to produce a global uncorrectable error signal with an error control decoder operating in a safe decoding mode; and

receiving at a recipient the at least two data packets and the global uncorrectable error signal.

13. The method of claim 12 further processing one data packet with the error control decoder operating while the safe decoding mode is off and sending the results of such processing to the recipient.

14. The method of claim 12 wherein the data packets are supplied from a memory, and the memory is partitioned into memory ranks.

15. The method of claim 14 further comprising storing information about persistent failures in the memory ranks in a table.

16. The method of claim 15 further comprising computing a memory rank score based upon the information in the table to enable or disabled the safe decoding mode.

17. A computer program product embodied in a tangible media comprising:

computer readable program codes coupled to the tangible media to improve miscorrection rates in error control code through buffering, the computer readable program codes configured to cause the program to;

process at least two data packets and apply a logic OR operation to the uncorrectable error signal related to the processing of the at least two data packets to produce a global uncorrectable error signal with an error control decoder operating in a safe decoding mode; and

receive at a recipient the at least two data packets and the global uncorrectable error signal.

18. The computer program product of claim 17 further comprising program code configured to:

process one data packet with the error control decoder operating while the safe decoding mode is off and sending the results of such to the recipient.

19. The computer program product of claim 17 further comprising program code configured to:

store in a table information about persistent failures in memory ranks of a memory that supplies requested data packets.

20. The computer program product of claim 19 further comprising program code configured to:

compute a memory rank score based upon the information in the table to enable or disabled the safe decoding mode.