(BEER): Determining DRAM On-Die ECC Functions by Exploiting DRAM Data Retention Characteristics
Bit-Exact ECC Recovery (BEER): Determining DRAM On-Die ECC Functions by Exploiting DRAM Data Retention Characteristics Minesh Pately Jeremie S. Kimzy Taha Shahroodiy Hasan Hassany Onur Mutluyz yETH Zurich¨ zCarnegie Mellon University Increasing single-cell DRAM error rates have pushed DRAM entirely within the DRAM chip [39, 76, 120, 129, 138]. On-die manufacturers to adopt on-die error-correction coding (ECC), ECC is completely invisible outside of the DRAM chip, so ECC which operates entirely within a DRAM chip to improve factory metadata (i.e., parity-check bits, error syndromes) that is used yield. e on-die ECC function and its eects on DRAM relia- to correct errors is hidden from the rest of the system. bility are considered trade secrets, so only the manufacturer Prior works [60, 97, 98, 120, 129, 133, 138, 147] indicate that knows precisely how on-die ECC alters the externally-visible existing on-die ECC codes are 64- or 128-bit single-error cor- reliability characteristics. Consequently, on-die ECC obstructs rection (SEC) Hamming codes [44]. However, each DRAM third-party DRAM customers (e.g., test engineers, experimental manufacturer considers their on-die ECC mechanism’s design researchers), who typically design, test, and validate systems and implementation to be highly proprietary and ensures not to based on these characteristics. reveal its details in any public documentation, including DRAM To give third parties insight into precisely how on-die ECC standards [68,69], DRAM datasheets [63,121,149,158], publi- transforms DRAM error paerns during error correction, we cations [76, 97, 98, 133], and industry whitepapers [120, 147].
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