SHF: Small: Enhancing Memory System Dependability by Integrity Checking

随着存储器单元密度及总容量持续增加，存储器系统可靠性日益成为关注点。最近的实地研究表明，记忆错误率正在上升，记忆错误已经证明了相关模式。在这两种趋势下，当前的存储器错误保护方案不再足以用于服务器计算机。这个项目探讨了一个独特的错误保护计划，称为MemGuard，这是基于内存完整性检查，以加强服务器计算机的内存错误保护，以及提供一个成本和能源效率的解决方案，为个人和移动的计算机。该研究可以显著提高计算机系统的可靠性，而不会产生高成本或能源开销。教育和推广活动将鼓励少数民族和妇女学生参与研究，并将包括与初中/高中学生和教师的互动。MemGuard方案使用基于散列的签名来检查内存读取和内存写入之间的一致性，以检测内存错误。 它可以检测到内存单元错误，假阴性率可以忽略不计。与SECDED（single error correcting double error detection）ECC和SDDC（single data device correction）方案相比，它在多比特错误检测方面更强大，并且成本和能量开销可以忽略不计。它不像其他两种方案那样立即纠正错误;相反，它可能会在操作系统检查点或程序重新启动时进行错误恢复。该项目将全面调查MemGuard的设计，评估MemGuard与真实DRAM错误模式的强度，将其扩展到多处理器和I/O丰富的环境，开发一个类似的基于完整性的处理器/内存通信错误保护方案，并将联合收割机MemGuard与现有的错误保护方案相结合。项目还将优化MemGuard哈希函数的设计和实现，将联合收割机MemGuard与选择错误保护相结合，探索高效的检查点策略，提高效率。

Memory system dependability is increasingly a concern as memory cell density and total capacity continue to increase. Recent field studies have shown that memory error rates are rising and memory errors have demonstrated correlation patterns. With these two trends, current memory error protection schemes are no longer sufficient for server computers. This project explores a unique error protection scheme called MemGuard, which is based on memory integrity checking, to enhance memory error protections for server computers as well as to provide a cost- and energy-efficient solution for personal and mobile computers. The research may significantly improve the dependability of computer systems without incurring high cost or energy overhead. The education and outreach activities will encourage minority and women students to get involved in the research, and will include interactions with middle/high school students and teachers.The MemGuard scheme checks the consistency between memory reads and memory writes using hash-based signatures to detect memory errors. It can detect memory cell errors with a negligible rate of false negative. Compared to SECDED (single error correcting double error detection) ECC and SDDC (single data device correction) schemes, it is much stronger in multi-bit error detection and with negligible cost and energy overhead. It does not correct errors immediately as the other two schemes do; instead, it may reply on OS checkpointing or program restarting for error recovery. The project will fully investigate the design of MemGuard, evaluate the strength of MemGuard with realistic DRAM error modes, extend it to multiprocessors and I/O rich environments, develop a similar integrity-based scheme for processor/memory communication error protection, and combine MemGuard with existing error protection schemes. The project will also optimize the design and implementation of the hash functions of MemGuard, combine MemGuard with selection error protection, and explore efficient checkpointing strategies for improved efficiency.