Corrigendum to: A Systematic Study of DDR4 DRAM Faults in the Field

TL;DR

This corrigendum corrects decoding errors in a previous study of DDR4 DRAM faults, leading to revised fault classifications and updated statistical results, thereby refining the original analysis.

Contribution

It identifies and corrects a bug in fault decoding, providing more accurate fault classification and updated data analysis in DDR4 DRAM field fault study.

Findings

Revised fault classification with more accurate single-bit fault counts

Updated failure rate metrics (FIT) for DDR4 DRAM devices

Clarified the distribution of fault modes after correction

Abstract

This paper is a corrigendum to the paper by Beigi et al. published at HPCA 2023 https://doi.org/10.1109/HPCA56546.2023.10071066. The HPCA paper presented a detailed field data analysis of faults observed at scale in DDR4 DRAM from two different memory vendors. This analysis included a breakdown of fault patterns or modes. Upon further study of the data, we found a bug in how we decoded errors based on the logged row-bank-column address. Specifically, we found that some errors that occurred in one column were mis-interpreted as occurring in two non-adjacent columns. As a result of this, some single-bit faults were misclassified as partial-row faults (i.e., two-bit faults). Similarly, some single-column faults were misclassified as two-column faults. The result of these misclassification errors is that the proportion of single-bit faults is higher than reported in the paper, with a commensurate reduction in the fraction of certain types of multi-bit faults. These misclassifications also slightly change the Failure In Time (FIT) per DRAM device values presented in the original paper. In this corrigendum, we provide an updated version of the relevant tables and figures and point out the corresponding page numbers and references in the original paper that they replace.