Methods and apparatus for maintaining characterized memory devices

1. A computerized method for monitoring a performance of characterized memories, the computerized method comprising:

accessing contents of a characterized memory at a characterized rate with a processor, wherein the characterized memory has one or more uncorrectable faults, the characterized memory characterized by a target performance based at least on the one or more uncorrectable faults;

determining an actual performance with the processor; and

refreshing the contents of the characterized memory with the processor based at least on the actual performance exceeding the target performance by a bound amount.

2. The computerized method of claim 1 , wherein the refreshing the contents of the characterized memory comprises re-writing the contents of the characterized memory with a pristine copy of the contents.

3. The computerized method of claim 1 , wherein the determining the actual performance is based at least on monitoring an increase in uncorrectable faults attributed to probabilistic errors.

4. The computerized method of claim 1 , wherein the accessing the contents of the characterized memory comprises a plurality of uniformly distributed memory reads over a memory space.

5. The computerized method of claim 1 , wherein the determining the actual performance comprises calculating a bit error rate (BER) based at least on the accessed contents and a pristine copy of the contents.

6. The computerized method of claim 1 , further comprising re-characterizing the characterized memory with a new target performance based at least on the actual performance exceeding the target performance by the bound amount.

7. The computerized method of claim 1 , wherein the determining the actual performance comprises determining a rate of change of faults.

8. The computerized method of claim 1 , wherein the determining the actual performance comprises determining a total accumulated number of faults.

9. The computerized method of claim 1 , wherein the target performance is based on a solution density function for an error-tolerant application.

10. A computerized method for estimating a degradation of one or more characterized memories, the computerized method comprising:

accessing contents of a characterized memory at a characterized rate with a processor, the characterized memory characterized by a target performance which is less than another target performance associated with another prescribed memory in data communication with the characterized memory;

determining an actual performance of the characterized memory with the processor based at least on the accessed contents and a pristine copy of the contents; and

based at least on the actual performance exceeding the target performance by a bound amount, triggering a remediation process for the characterized memory.

11. The computerized method of claim 10 , wherein the determining the actual performance with the processor based at least on the accessed contents and the pristine copy of the contents further comprises identifying uncorrectable faults.

12. The computerized method of claim 11 , wherein the remediation process comprises causing a replacement of the characterized memory based at least on the uncorrectable faults exceeding a threshold amount.

13. The computerized method of claim 11 , wherein the remediation process comprises refreshing the contents of the characterized memory based at least on the uncorrectable faults not exceeding a threshold amount.

14. The computerized method of claim 10 , wherein the determining the actual performance with the processor based at least on the accessed contents and the pristine copy of the contents further comprises identifying correctable faults.

15. The computerized method of claim 14 , further comprising repairing the correctable faults.

16. A computerized apparatus configured to remedy faults in one or more characterized memories, the computerized apparatus comprising:

a characterized memory comprising one or more uncorrectable faults, the characterized memory (i) configured to accumulate one or more correctable faults probabilistically during use, and (ii) characterized by a target performance level based at least on a solution density function for an error-tolerant application;

a processor configured to access the characterized memory at a characteristic rate; and

controller logic configured to, when executed by the processor, determine a performance metric based at least on the one or more uncorrectable faults and the one or more correctable faults;

wherein the controller logic is configured to:

refresh the characterized memory based at least on a number of correctable faults exceeding a first threshold;

flag the characterized memory for replacement based at least on a number of uncorrectable faults exceeding a second threshold; and

re-characterize the characterized memory with another target performance level based at least on the determined performance metric.

17. The computerized apparatus of claim 16 , wherein the one or more uncorrectable faults comprise probabilistic errors and hardware failures that (i) cannot be repaired or (ii) exceed a limitation of error correcting capability.

18. The computerized apparatus of claim 16 , wherein the controller logic is further configured to fuse replacement cells to repair hardware failures.

19. The computerized apparatus of claim 16 , wherein the controller logic is further configured to correct errors with an error correcting code.

20. The computerized apparatus of claim 16 , further comprising a pristine memory; and

wherein the controller logic is configured to refresh the characterized memory with data stored the pristine memory.