@phdthesis{Traue2018, author = {Traue, Jana}, title = {Fine-grained transactions for NVRAM}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-46367}, school = {BTU Cottbus - Senftenberg}, year = {2018}, abstract = {For decades, there has been a distinction between fast, volatile and slow, non-volatile memory technologies in the storage hierarchy of computer systems. While volatile memories offer a byte addressable interface, persistence was limited to slower, block-oriented media. As a consequence, processing and storing information implies copying data from the persistent storage to volatile memory and vice versa. In recent years, a new memory technology which is both byte-addressable and non-volatile has been announced: Non-Volatile Random Access Memory (NVRAM). Its unique combination of features allows processing of information exactly at the location where it is stored permanently, thereby eliminating the need for copies. Without the need to create and manage copies, data can be processed significantly faster. The processing of persistent information can be disrupted by failures, like crashes. When changes are only partially performed, data might be left in an inconsistent state. Such a situation can be avoided by creating a copy before starting to change data. That backup is restored when a failure has been detected. Such a procedure relies on a highly specific order of its operations, because the backup can only be disposed after all changes have been carried out successfully. Since NVRAM removes the need for accessing block-oriented media, it removes a major bottleneck in the processing of persistent information, especially when only small amounts of data are modified. As a result, controlling the order of operations dominates the processing performance. This thesis analyses transactional mechanisms for data on NVRAM which can guarantee that sequences of operations are either carried out as one unit or not at all. The idea is based on creating backups, as sketched above. Existing approaches for the traditional storage hierarchy use separate memory locations for backup and modified data. In a first step, the costs of applying existing procedures to NVRAM are identified. Afterwards, a novel approach which couples the versions tighter in space is presented. Enabled by the unique properties of NVRAM, this new approach is able to reduce the costs of ordering. The processing of persistent data can thereby be sped up significantly.}, subject = {NVRAM; Transactions; Cache lines; Non-volatile; Main memory; Nicht-fl{\"u}chtig; Hauptspeicher; Cache-Line; Transaktionen; NVRAM; Hauptspeicher; RAM; Transaktion; Sicherungskopie}, language = {en} }