A Realistic Evaluation of Memory Hardware Errors and Software System Susceptibility Xin Li, Michael C. Huang, and Kai Shen Lingkun Chu University of Rochester Ask.com Memory hardware reliability is an indispensable part of whole-system dependability. Its importance is evidenced by a plethora of prior research work studying the impact of memory errors on software systems. However, the absence of solid understanding of the error characteristics prevents software system researchers from making well reasoned assumptions, and it also hinders the careful evaluations over different choices of fault tolerance design. In this paper, we present our realistic memory hardware error traces collected from production computer systems with more than 800GB memory for around nine months. Based on the traces (including detailed information on the error addresses and patterns), we explore the implications of different hardware ECC protection schemes so as to identify the most common error causes and approximate error rates exposed to the software level. Lastly, we investigate the software system susceptibility to some major error causes, with the particular goal to validate, question, and augment results of prior system studies.