Erase health metric to rank memory portions
First Claim
1. A method, comprising:
- for each of a plurality of non-volatile memory portions of a non-volatile memory device, determining a respective erase health metric for each of the plurality of non-volatile memory portions by combining an erase difficulty metric and an age metric, including;
calculating the erase difficulty metric for a respective non-volatile memory portion, wherein the erase difficulty metric for the respective non-volatile memory portion is based on one or more erase performance metrics obtained during a plurality of erase phases of an erase operation performed on the respective non-volatile memory portion;
wherein;
each of the plurality of erase phases of the erase operation performed on the respective non-volatile memory portion comprises;
performing an erase using an erase voltage; and
determining an erase statistic for the performed erase, wherein the erase statistic for the performed phase includes a number of non-erased memory cells in the respective non-volatile memory portion having cell voltages that fail to satisfy a criterion corresponding to the performed erase; and
the one or more erase performance metrics include;
the number of non-erased memory cells in the respective non-volatile memory portion; and
a change in voltage between an initial erase voltage used during an initial erase phase of the erase operation on the respective non-volatile memory portion, and a final erase voltage used in a final erase phase of the erase operation on the respective non-volatile memory portion; and
determining the age metric for the respective non-volatile memory portion based on a total number of erase operations performed on the respective non-volatile memory portion during a lifespan of the non-volatile memory device; and
after determining the respective erase health metric for each of the plurality of non-volatile memory portions of the non-volatile memory device;
ranking non-volatile memory portions, including at least the plurality of non-volatile memory portions of the non-volatile memory device, in accordance with the determined respective erase health metrics; and
selecting a non-volatile memory portion of the plurality of non-volatile memory portions in accordance with the ranking of the non-volatile memory portions, and writing data to the selected non-volatile memory portion.
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Accused Products
Abstract
An exemplary method to rank blocks of a non-volatile memory device includes: for each of a plurality of blocks of a memory device, determining a respective erase health metric (EHM) for each of the blocks by combining an erase difficulty metric and an age metric, including: calculating the erase difficulty metric for a respective block based on erase performance metrics obtained during erase phases of an erase operation performed on the respective block, and determining the age metric for the respective block based on a total number of erase operations performed on the respective block during its lifespan. After determining the respective EHM for each of the blocks, the method includes ranking blocks in accordance with the determined respective EHMs, and selecting a block of the plurality of blocks in accordance with the rankings, and writing data to the selected block.
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Citations
18 Claims
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1. A method, comprising:
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for each of a plurality of non-volatile memory portions of a non-volatile memory device, determining a respective erase health metric for each of the plurality of non-volatile memory portions by combining an erase difficulty metric and an age metric, including; calculating the erase difficulty metric for a respective non-volatile memory portion, wherein the erase difficulty metric for the respective non-volatile memory portion is based on one or more erase performance metrics obtained during a plurality of erase phases of an erase operation performed on the respective non-volatile memory portion; wherein; each of the plurality of erase phases of the erase operation performed on the respective non-volatile memory portion comprises; performing an erase using an erase voltage; and determining an erase statistic for the performed erase, wherein the erase statistic for the performed phase includes a number of non-erased memory cells in the respective non-volatile memory portion having cell voltages that fail to satisfy a criterion corresponding to the performed erase; and the one or more erase performance metrics include; the number of non-erased memory cells in the respective non-volatile memory portion; and a change in voltage between an initial erase voltage used during an initial erase phase of the erase operation on the respective non-volatile memory portion, and a final erase voltage used in a final erase phase of the erase operation on the respective non-volatile memory portion; and determining the age metric for the respective non-volatile memory portion based on a total number of erase operations performed on the respective non-volatile memory portion during a lifespan of the non-volatile memory device; and after determining the respective erase health metric for each of the plurality of non-volatile memory portions of the non-volatile memory device; ranking non-volatile memory portions, including at least the plurality of non-volatile memory portions of the non-volatile memory device, in accordance with the determined respective erase health metrics; and selecting a non-volatile memory portion of the plurality of non-volatile memory portions in accordance with the ranking of the non-volatile memory portions, and writing data to the selected non-volatile memory portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A storage system, comprising:
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a storage medium; one or more processors; and memory storing one or more programs, which when executed by the one or more processors cause the storage system to; for each of a plurality of non-volatile memory portions of a non-volatile memory device, determine a respective erase health metric for each of the plurality of non-volatile memory portions by combining an erase difficulty metric and an age metric, including; calculate the erase difficulty metric for a respective non-volatile memory portion, wherein the erase difficulty metric for the respective non-volatile memory portion is based on one or more erase performance metrics obtained during a plurality of erase phases of an erase operation performed on the respective non-volatile memory portion; wherein; each of the plurality of erase phases of the erase operation performed on the respective non-volatile memory portion comprises; performing an erase using an erase voltage; and determining an erase statistic for the performed erase, wherein the erase statistic for the performed phase includes a number of non-erased memory cells in the respective non-volatile memory portion having cell voltages that fail to satisfy a criterion corresponding to the performed erase; and the one or more erase performance metrics include; the number of non-erased memory cells in the respective non-volatile memory portion; and a change in voltage between an initial erase voltage used during an initial erase phase of the erase operation on the respective non-volatile memory portion, and a final erase voltage used in a final erase phase of the erase operation on the respective non-volatile memory portion; and determine the age metric for the respective non-volatile memory portion based on a total number of erase operations performed on the respective non-volatile memory portion during a lifespan of the non-volatile memory device; and after determining the respective erase health metric for each of the plurality of non-volatile memory portions of the non-volatile memory device; rank non-volatile memory portions, including at least the plurality of non-volatile memory portions of the non-volatile memory device, in accordance with the determined respective erase health metrics; and select a non-volatile memory portion of the plurality of non-volatile memory portions in accordance with the ranking of the non-volatile memory portions, and write data to the selected non-volatile memory portion. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A storage system, comprising:
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means for determining, for each of a plurality of non-volatile memory portions of a non-volatile memory device, a respective erase health metric for each of the plurality of non-volatile memory portions by combining an erase difficulty metric and an age metric, including; means for calculating the erase difficulty metric for a respective non-volatile memory portion, wherein the erase difficulty metric for the respective non-volatile memory portion is based on one or more erase performance metrics obtained during a plurality of erase phases of an erase operation performed on the respective non-volatile memory portion; wherein; each of the plurality of erase phases of the erase operation performed on the respective non-volatile memory portion comprises; performing an erase using an erase voltage; and determining an erase statistic for the performed erase, wherein the erase statistic for the performed phase includes a number of non-erased memory cells in the respective non-volatile memory portion having cell voltages that fail to satisfy a criterion corresponding to the performed erase; and the one or more erase performance metrics include; the number of non-erased memory cells in the respective non-volatile memory portion; and a change in voltage between an initial erase voltage used during an initial erase phase of the erase operation on the respective non-volatile memory portion, and a final erase voltage used in a final erase phase of the erase operation on the respective non-volatile memory portion; and means for determining the age metric for the respective non-volatile memory portion based on a total number of erase operations performed on the respective non-volatile memory portion during a lifespan of the non-volatile memory device; and means for ranking non-volatile memory portions, including at least the plurality of non-volatile memory portions of the non-volatile memory device, in accordance with the determined respective erase health metrics; and means for selecting a non-volatile memory portion of the plurality of non-volatile memory portions in accordance with the ranking of the non-volatile memory portions, and write data to the selected non-volatile memory portion.
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Specification