Uncovering The Size, Structure, And Operation Of DRAM Subarrays And Showing Experimental Results Supporting The Cause Of Rowhammer


A technical paper titled “X-ray: Discovering DRAM Internal Structure and Error Characteristics by Issuing Memory Commands” was published by researchers at Seoul National University and University of Illinois at Urbana-Champaign.


“The demand for accurate information about the internal structure and characteristics of dynamic random-access memory (DRAM) has been on the rise. Recent studies have explored the structure and characteristics of DRAM to improve processing in memory, enhance reliability, and mitigate a vulnerability known as rowhammer. However, DRAM manufacturers only disclose limited information through official documents, making it difficult to find specific information about actual DRAM devices.
This paper presents reliable findings on the internal structure and characteristics of DRAM using activate-induced bitflips (AIBs), retention time test, and row-copy operation. While previous studies have attempted to understand the internal behaviors of DRAM devices, they have only shown results without identifying the causes or have analyzed DRAM modules rather than individual chips. We first uncover the size, structure, and operation of DRAM subarrays and verify our findings on the characteristics of DRAM. Then, we correct misunderstood information related to AIBs and demonstrate experimental results supporting the cause of rowhammer. We expect that the information we uncover about the structure, behavior, and characteristics of DRAM will help future DRAM research.”

Find the technical paper here. Published: June 2023 (preprint).

Nam, Hwayong, Seungmin Baek, Minbok Wi, Michael Jaemin Kim, Jaehyun Park, Chihun Song, and Nam Sung Kim. “X-ray: Discovering DRAM Internal Structure and Error Characteristics by Issuing Memory Commands.” arXiv preprint arXiv:2306.03366 (2023).

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