Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Experimental Characterization, Optimization, and Recovery of Data
  Retention Errors in MLC NAND Flash Memory   This paper summarizes our work on experimentally characterizing, mitigating,
and recovering data retention errors in multi-level cell (MLC) NAND flash
memory, which was published in HPCA 2015, and examines the work's significance
and future potential. Retention errors, caused by charge leakage over time, are
the dominant source of flash memory errors. Understanding, characterizing, and
reducing retention errors can significantly improve NAND flash memory
reliability and endurance. In this work, we first characterize, with real 2Y-nm
MLC NAND flash chips, how the threshold voltage distribution of flash memory
changes with different retention ages -- the length of time since a flash cell
was programmed. We observe from our characterization results that 1) the
optimal read reference voltage of a flash cell, using which the data can be
read with the lowest raw bit error rate (RBER), systematically changes with its
retention age, and 2) different regions of flash memory can have different
retention ages, and hence different optimal read reference voltages.
  Based on our findings, we propose two new techniques. First, Retention
Optimized Reading (ROR) adaptively learns and applies the optimal read
reference voltage for each flash memory block online. The key idea of ROR is to
periodically learn a tight upper bound of the optimal read reference voltage,
and from there approach the optimal read reference voltage. Our evaluations
show that ROR can extend flash memory lifetime by 64% and reduce average error
correction latency by 10.1%. Second, Retention Failure Recovery (RFR) recovers
data with uncorrectable errors offline by identifying and probabilistically
correcting flash cells with retention errors. Our evaluation shows that RFR
essentially doubles the error correction capability.

16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an