Random read tracking in non-volatile memory devices
The present disclosure relates to systems, apparatuses, methods, and non-transitory computer-readable media including a non-volatile memory and a controller operatively coupled to the non-volatile memory. The controller is to determine information on a number of errors for a page for reading data stored in the page of the non-volatile memory, and the data is read using a first read threshold. The controller is to determine a second read threshold based at least in part on the first read threshold and the number of page errors for the page and apply the second read threshold for subsequently reading data stored on the page according to a decision rule.
1 . A system, comprising:
a non-volatile memory; and
a controller operatively coupled to the non-volatile memory, wherein the controller is to:
determine information on a number of errors for a page of the non-volatile memory that occur while reading data stored in the page, wherein the data is read using a first read threshold;
determine a second read threshold based at least in part on the first read threshold and the information on the number of errors for the page; and
apply the second read threshold for subsequently reading data stored on the page according to a decision rule.
2 . The system of claim 1 , wherein reading the data comprises a single page read operation on the page of the non-volatile memory.
3 . The system of claim 1 , wherein the information on the number of the errors for the page comprises a Failed Bit Count (FBC) value and a direction of the errors.
4 . The system of claim 3 , wherein the direction of the errors comprises:
a first direction corresponding to reading “0” as “1” or a zero-to-one error; and
a second direction corresponding to reading “1” as a “0” or a one-to-zero error.
5 . The system of claim 3 , wherein the controller is to determine the second read threshold in response to determining that:
the FBC value is higher than an FBC threshold;
a ratio of the second direction of errors to the first direction of errors is higher than an error ratio threshold.
6 . The system of claim 1 , wherein the information on the number of errors for the page comprises an actual number of errors for a given size of the page.
7 . The system of claim 1 , wherein the second read threshold is determined based at least in part on the first read threshold, the information on the number of errors for the page, and a page type.
8 . The system of claim 1 , wherein the page type comprises at least one of a top page, upper page, middle page, or lower page.
9 . The system of claim 1 , wherein the first read threshold corresponds to a first shift index, and the second read threshold corresponds to a second shift index.
10 . The system of claim 9 , wherein the controller is to:
perform hard bit decoding (HB-DEC) for the first shift index;
determine that the HB-DEC fails for the first shift index;
perform the HB-DEC for the second shift index;
determine that the HB-DEC succeeds for the first shift index; and
update a History Table (HT) using the second shift index according to the decision rule.
11 . The system of claim 10 , wherein the HT is updated using the second shift index in response to determining that a Bit Error Rate (BER) for the second shift index is greater than a BER threshold.
12 . The system of claim 10 , wherein updating the HT comprises replacing a default shift index of the HT with the second shift index.
13 . The system of claim 10 , wherein the HT comprises a plurality of shift indices corresponding to Data Retention (DR).
14 . The system of claim 9 , wherein
the first shift index comprises at least one read threshold comprising the first read threshold; and
the second shift index comprises at least one read threshold comprising the second read threshold.
15 . The system of claim 1 , wherein the controller is to:
store the information on the number of errors for the page and Meta Data (MD) in a First-In First Out (FIFO); and
retrieve the information on the number of errors for the page and the MD to determine the second read threshold.
16 . The system of claim 15 , wherein the MD comprises at least one of a page type, a previous shift index, and a cycle count.
17 . At least one non-transitory computer readable medium including one or more instructions stored thereon and executable by a processor to:
determine information on a number of errors for a page of the non-volatile memory that occur while reading data stored in the page, wherein the data is read using a first read threshold;
determine a second read threshold based at least in part on the first read threshold and the information on the number of page errors for the page; and
apply the second read threshold for subsequently reading data stored on the page according to a decision rule.
18 . The at least one non-transitory computer readable medium of claim 17 , wherein
the information on the number of the errors for the page comprises a Failed Bit Count (FBC) value and a direction of the errors; and
the direction of the errors comprises:
a first direction corresponding to reading “0” as “1” or a zero-to-one error; and
a second direction corresponding to reading “1” as a “0” or a one-to-zero error.
19 . A method, comprising:
determining information on a number of errors for a page of the non-volatile memory that occur while reading data stored in the page, wherein the data is read using a first read threshold;
determining a second read threshold based at least in part on the first read threshold and the information on the number of page errors for the page; and
applying the second read threshold for subsequently reading data stored on the page according to a decision rule.
20 . The method of claim 19 , wherein
the information on the number of the errors for the page comprises a Failed Bit Count (FBC) value and a direction of the errors; and
the direction of the errors comprises:
a first direction corresponding to reading “0” as “1” or a zero-to-one error; and
a second direction corresponding to reading “1” as a “0” or a one-to-zero error.