CSR: Small: Fault-Tolerant Distributed Software Transactional Memory: Theory, Protocols, and Java Package

该项目旨在开发容错分布式事务内存（DTM）的协议、机制和Java实现。DTM承诺减轻基于锁的分布式并发控制的可编程性、可伸缩性和性能挑战。容错性对于DTM处理节点/网络故障至关重要，而对象复制是实现这一目标的核心。复制协议必须是可伸缩的，并确保事务正确性和进度属性。预期的结果是一个新的复制DTM框架，其关键思想是将事务分成两个具有正交职责的独立阶段：1)常规读/写阶段，快速查找和获取所需对象的最新副本，而不进行并发控制；2)请求-提交阶段，进行（分布式）并发控制。该项目研究了基于仲裁的复制协议的使用，该协议在读/写仲裁中维护事务性元数据，并通过利用仲裁交集属性进行可扩展的并发控制。复制的DTM框架和协议在开源的HyFlow DTM Java包（hyflow.org）中实现。容错DTM有潜力提高包括防御系统在内的各种高级分布式计算应用程序的可靠性和性能。该项目计划将该技术（技术和HyFlow实现）转移到美国国防部的生产系统中，以利用容错DTM的优势。这是一项具有直接潜在经济效益和社会效益的研究。此外，该项目的成果将被纳入弗吉尼亚理工大学的研究生课程，其中包括弗吉尼亚州布莱克斯堡的学生，弗吉尼亚州美国海军水面作战中心达尔格伦分部（NSWCDD）的科学家和工程师，通过弗吉尼亚理工大学在NSWCDD的研究生外展计划，以及中东和北非的学生通过弗吉尼亚理工大学在埃及的VT-MENA计划。

The project is to develop protocols, mechanisms, and a Java implementation of fault-tolerant distributed transactional memory (DTM). DTM promises to alleviate the programmability, scalability, and performance challenges of lock-based distributed concurrency control. Fault-tolerance is essential to DTM to cope with node/network failures, and object replication is central toward achieving this. Replication protocols must be scalable and ensure transactional correctness and progress properties. The expected outcome is a novel replicated DTM framework, whose key idea is to split transactions into two independent phases with orthogonal responsibilities: 1) regular read/write phases, which quickly look-up and fetch latest copies of required objects without concurrency control, and 2) a request-commit phase, which does (distributed) concurrency control. The project investigates the use of quorum-based replication protocols, which maintain transactional metadata in read/write quorums, and do scalable concurrency control by exploiting the quorum intersection property. The replicated DTM framework and protocols are implemented in the open-source HyFlow DTM Java package (hyflow.org). Fault tolerant DTM has potential to improve both reliability and performance of a broad range of advanced distributed computing applications, including defense systems. The project has plans to transitioning this technology (techniques and HyFlow implementation) to a production system of the US Department of Defense, to leverage the benefits of fault-tolerant DTM. This is a direct potential economic and social benefit of the research. Additionally, the project's results are being incorporated into a graduate course at Virginia Tech that includes students at Blacksburg, VA, scientists and engineers at US Naval Surface Warfare Center Dahlgren Division (NSWCDD), VA through Virginia Tech's graduate outreach program at NSWCDD, and students in the Middle East and North Africa through Virginia Tech's VT-MENA program at Egypt.