Configuring storage cells
Apparatuses, systems, methods, and computer program products are disclosed for configuring storage cells. A method includes determining a usage history for a set of storage cells of a solid-state storage medium. A method includes adjusting a voltage threshold for a set of storage cells by an amount based at least in part on a usage history. A method includes configuring a set of storage cells to use an adjusted voltage threshold.
1. An apparatus comprising:
a data set read module configured to detect a shift in a read voltage level past a read voltage threshold for a set of memory cells of a non-volatile memory medium;
an adjustment module configured to, in response to the shift in the read voltage level, adjust a read voltage threshold for the set of memory cells by an amount based at least in part on one or more characteristics of the set of memory cells; and
a read voltage module configured to configure the set of memory cells to use the adjusted read voltage threshold;
wherein the adjustment module is external to the non-volatile memory medium.
2. The apparatus of claim 1 , further comprising a persistence module configured to retain the adjusted read voltage threshold for the set of memory cells.
3. The apparatus of claim 2 , wherein the persistence module is configured to store different read voltage thresholds for different sub-groupings of the set of memory cells.
4. The apparatus of claim 3 , wherein the read voltage module is configured to reconfigure the entire set of memory cells to use one of the different read voltage thresholds in response to a read request for a sub-grouping associated with the one of the different read voltage thresholds.
5. The apparatus of claim 2 , wherein the persistence module is configured to send the adjusted read voltage threshold to the non-volatile memory medium for each read operation for the set of storage cells.
6. The apparatus of claim 1 , wherein the one or more characteristics include one or more of a usage history for the set of memory cells, an error history for the set of memory cells, an age for the set of memory cells, a number of program and erase cycles for the set of memory cells, and an amount of wear for the set of memory cells.
7. The apparatus of claim 1 , wherein the data set read module is further configured to detect the shift in the read voltage level by detecting a data error for the set of memory cells.
8. The apparatus of claim 1 , wherein the data set read module is further configured to detect the shift in the read voltage level in response to a testing operation for the set of memory cells.
9. An apparatus comprising:
means for determining a number of program and erase cycles for a set of storage cells of a solid-state storage medium; and
means for compensating for a change in read voltage levels for the set of storage cells based at least in part on the number of program and erase cycles; wherein the means for compensating are external to the solid-state storage medium.
10. The apparatus of claim 9 , further comprising means for persisting an adjustment that compensates for the change in read voltage levels.
11. The apparatus of claim 10 , wherein the means for persisting the adjustment comprises means for persisting different adjustments for different sets of storage cells.
12. The apparatus of claim 9 , wherein compensating for the change in read voltage levels comprises adjusting a read voltage threshold for the set of storage cells, an amount of the adjustment based at least in part on the number of program and erase cycles.
13. A method comprising:
determining a usage history for a set of storage cells of a solid-state storage medium;
adjusting a voltage threshold for the set of storage cells by an amount based at least in part on the usage history; and
configuring the set of storage cells to use the adjusted voltage threshold;
wherein said adjusting is performed by a module external to the solid-state storage medium.
14. The method of claim 1 , wherein the amount is based at least in part on a difference between a bias for data of the storage cells and a known bias.
15. The method of claim 1 , wherein a direction for adjusting the voltage threshold is determined based on a deviation of a bias for data of the storage cells from a known bias.
16. The method of claim 1 , wherein the voltage threshold comprises a read voltage threshold.
17. The method of claim 1 , wherein the voltage threshold comprises a program voltage.
18. The method of claim 1 , wherein the usage history comprises a number of program and erase cycles for the set of storage cells.
19. The method of claim 1 , wherein the usage history comprises an error history for the set of storage cells.
20. The method of claim 1 , wherein adjusting the voltage threshold is in response to detecting a read error for the set of storage cells.