| 摘要 |
The present invention includes embodiments of systems and methods for increasing the operational efficiency and extending the estimated operational lifetime of a flash memory storage device (and its component flash memory chips, LUNs and blocks of flash memory) by monitoring the health of the device and its components and, in response, adaptively tuning the operating parameters of flash memory chips during their operational lifetime, as well as employing other less extreme preventive measures in the interim, via an interface that avoids the need for direct access to the test modes of the flash memory chips. In an offline characterization phase, “test chips” from a batch of recently manufactured flash memory chips are used to simulate various usage scenarios and measure the performance effects of writing and attempting to recover (read) test patterns written with different sets of operating parameters over time (simulating desired retention periods). |
| 主权项 |
1. An offline characterization system that generates, during an offline characterization phase prior to the operational lifetime of a flash memory chip, an optimal set of operating parameter values associated with a LUN in the flash memory chip, wherein the flash memory chip includes one or more LUNs, each LUN includes one or more blocks of flash memory and an associated set of one or more n-bit control registers, and each control register stores the value of an operating parameter associated with that LUN, the offline characterization system comprising:
(a) a candidate generator that utilizes one or more predictive models to generate a candidate score for each of a plurality of potential candidates, wherein:
(i) each potential candidate represents a set of operating parameter values that potentially will be stored in the control registers of a LUN of the flash memory chip,(ii) the candidate score for each potential candidate represents a prediction of a hardware score that would be generated from hardware testing of the flash memory chip in accordance with the set of operating parameter values represented by that potential candidate, and(iii) the candidate generator selects, from the plurality of potential candidates, one or more actual candidates for hardware testing based upon the candidate score of each potential candidate; (b) a hardware tester that:
(i) conducts one or more hardware tests upon each of the actual candidates by storing the operating parameter values represented by that actual candidate in the control registers of the LUN of the flash memory chip, and performing read, write and erase operations on the flash memory chip in accordance with the stored operating parameter values,(ii) generates a hardware score for each of the actual candidates based upon the results of the one or more hardware tests; and (c) a candidate selector that selects the set of operating parameter values represented by the actual candidate with the highest hardware score as the optimal set of operating parameter values associated with the LUN. |
