X-ray: Discovering DRAM Internal Structure and Error Characteristics by Issuing Memory Commands

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