SHF: Small: Memory Persistency: programming paradigms for byte-addressable, non-volatile memories

十多年来，工业界和学术界的研究人员一直在寻找新的技术来存储数据，以便以低廉的成本存储大量数据并快速访问。 今天，计算机系统通常有三种类型的数据存储：旋转磁盘，用于便宜但缓慢，长期，批量数据存储;主存储器，用于快速但昂贵的数据访问应用程序正在积极使用;和闪存，其行为很像旋转磁盘，但提供更快的访问速度，每比特的价格更高。 然而，我们现在正处于新的存储技术的可用性的风口浪尖，提供接近主内存的性能，但可以持久地存储数据？也就是说，当电脑关机的时候？在闪存和主存储器之间的每比特成本。 这些新的非易失性存储器设备在存储器和闪存之间向计算机系统数据存储层次结构添加了新的层。 在十年内，包含这些新的非易失性存储器的系统将变得广泛可用。 事实上，随着成本和制造工艺的改善，这种存储器可能成为“物联网”中小型设备的首选存储设备，并对云系统的性能和可恢复性至关重要。这些新存储器开辟了探索在计算机系统断电时存储数据的新格式和结构的可能性。 与磁盘和闪存不同，非易失性存储器中的数据可以以非常细的粒度访问？各个数据项（例如，bytes）？而不是粗粒度的数据块。 这种细粒度访问支持开发数据结构，即使在意外断电的情况下也能可靠地存储数据，而且比磁盘或闪存上的数据存储具有更高的性能和简单性。 现有的计算机主存储器系统没有考虑到跨电源故障的耐久性而设计，因为当电源故障时数据丢失，并且因此不试图维持数据被写入存储器的任何特定顺序。 然而，控制这种写入数据的顺序对于允许系统在写入过程中发生电源故障时恢复并继续操作至关重要。 该研究项目将为程序员开发新的方法，以有效和轻松地设计高性能的数据结构，通过仔细控制数据记录的顺序，可以从意外故障中恢复。 该研究将与行业密切合作，并与主要研究者？操作系统和并行计算机体系结构课程。

For over a decade, researchers in industry and academia have sought new techniques to store data so vast amounts of data can be stored inexpensively and accessed quickly. Today, computer systems typically have three kinds of data storage: rotating disks for cheap-but-slow, long-term, bulk data storage; main memory for fast, but expensive access to data applications are actively using; and FLASH, which behaves much like rotating disks, but offers somewhat faster access at a higher price per bit. However, we are now at the cusp of availability of new storage technologies that offer performance close to that of main memory, but can store data durably?that is, when the computer is powered off?at a cost per bit between Flash and main memory. These new non-volatile memory devices add a new layer to the computer system data storage hierarchy between memory and FLASH. Within a decade, systems incorporating these new non-volatile memories will become widely available. Indeed, as cost and manufacturing processes improve, such memories may become the preferred storage for small devices in the ``Internet of Things'' and become critical to performance and recoverability in cloud systems. These new memories open up the possibility to explore new formats and structures for storing data across computer system power failures. Unlike disk and FLASH, data in non-volatile memories can be accessed at very fine granularity?individual data items (e.g., bytes)?rather than coarse-grained blocks of data. This fine-grain access enables the development of data structures that reliably store data even if power fails unexpectedly, but with greater performance and simplicity than data storage on disk or FLASH. Existing computer main memory systems have not been designed with durability across power failures in mind, since the data is lost when power fails, and therefore do not try to maintain any specific order in which data is written to memory. However, controlling this order of writing data is critical to allowing a system to recover and continue operation if power fails while writes are in progress. This research project will develop new ways for programmers to efficiently and easily design high-performance data structures that can recover from unexpected failures by carefully controlling the order in which data is recorded. The research will be performed in close collaboration with industry, and integrated with the principal investigators? course offerings in operating systems and parallel computer architecture.