SHF: Small: Enhancing Memory System Dependability by Integrity Checking

随着存储单元密度和总容量的不断增加，存储系统的可靠性日益受到关注。最近的实地研究表明，记忆错误率正在上升，记忆错误表现出相关模式。在这两种趋势下，当前的内存错误保护方案对于服务器计算机已不再足够。该项目探索了一种独特的错误保护方案，称为MemGuard，它基于内存完整性检查，以增强服务器计算机的内存错误保护，并为个人和移动计算机提供成本和节能的解决方案。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，并将包括与初高中学生和教师的互动。MemGuard方案使用基于哈希的签名检查内存读和写之间的一致性，以检测内存错误。它能以可忽略不计的假阴性率检测记忆细胞错误。与SECDED（单错误纠错双错误检测）ECC和SDDC（单数据设备纠错）方案相比，它在多比特错误检测方面要强大得多，并且成本和能源开销可以忽略不计。它不像其他两种方案那样能立即纠正错误；相反，它可能会在操作系统检查点或程序重新启动时回复错误恢复。该项目将充分研究MemGuard的设计，评估MemGuard在实际DRAM错误模式下的强度，将其扩展到多处理器和I/O丰富的环境中，开发类似的基于完整性的处理器/内存通信错误保护方案，并将MemGuard与现有的错误保护方案结合起来。该项目还将优化MemGuard哈希函数的设计和实现，将MemGuard与选择错误保护相结合，并探索有效的检查点策略以提高效率。

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.