Selective retirement of blocks
AssigneeApple Inc.
InventorsMatthew Byom, Daniel J. Post, Vadim Khmelnitsky
Life of this patent
Estimating the term…
Abstract
Systems and methods are provided for selectively retiring blocks based on refresh events of those blocks. In addition to refresh events, other criteria may be applied in making a decision whether to retire a block. By applying the criteria, the system is able to selectively retire blocks that may otherwise continue to be refreshed.
Claims20
A method for selectively retiring blocks comprising:
- monitoring blocks that experience refresh events;
- adding blocks that experience refresh events to a list;
- maintaining characteristics associated with the blocks in the list;
- applying at least two different criteria to the blocks in the list to determine if any one or more of the blocks should be retired;
- and
- retiring any blocks that meet the at least two criteria.
A system comprising a processor and non-volatile memory, the processor operative to:
- monitor a number of times a superblock has been refreshed;
- determine if the superblock has refreshed at least a predetermined number of times during a given period of time;
- if the superblock has refreshed at least the predetermined number of times during the given period of time, determine a physical block within the superblock that is responsible for causing the superblock to experience refresh events;
- and
- retire the physical block.
A method for selectively retiring blocks comprising:
- providing a plurality of superblocks, each superblock comprising a physical block from two or more planes of physical blocks;
- maintaining, for each superblock, a counter of the number of times the superblock is refreshed;
- updating the counter for a given superblock when the given superblock is refreshed;
- determining if the given superblock has refreshed more than a predetermined number of times within a predetermined period of time;
- and
- retiring at least one physical block included as part of the given superblock if it is determined that the given superblock has refreshed more than the predetermined number of times within the predetermined period of time.
A method for selectively retiring blocks, comprising:
- refreshing a superblock, the superblock comprising physical blocks from two or more planes of physical blocks;
- programming the physical blocks;
- reading, after the physical blocks are programmed, back the data to check for an error;
- determining whether the error exceeds a refresh threshold;
- and
- in response to determining that the error exceeds the refresh threshold:
- determining which physical block in the physical blocks is responsible for causing the physical blocks to exceed the refresh threshold;
- and
- retiring the responsible physical block.
A method for selectively retiring blocks, comprising:
- providing a plurality of blocks that are arranged in a plurality of planes;
- maintaining a list of potential blocks suitable for retirement;
- determining if a given block in the list has been refreshed over N number of times, N being an number greater than zero;
- determining if a percentage of retired blocks in the plane of the given block is less than Q percentage, Q being a number greater than zero;
- and
- retiring the given block if the given block has been refreshed over N number of times and the percentage of retired blocks in the plane of the given block is less than Q percentage.
Dependencies are inferred from the claim text.