Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Yalamanchili, Sudhakar; Committee Member: Riley, George; Committee Member: Schimmel, David. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Computer Science, 2009. / Includes bibliographical references.

Thesis (M.S.)--University of Florida, 2004. / Title from title page of source document. Document formatted into pages; contains 85 pages. Includes vita. Includes bibliographical references.

Thesis (Ph.D.) -- University of Rhode Island, 2009. / Typescript. Includes bibliographical references (leaves 128-137).

Thesis (Ph. D.)--University of Washington, 1981. / Vita. Bibliography: leaves [173]-177.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 82-84). Also available in electronic version.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (MScEng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Flash memory and the errors induced in it by radiation were studied. A test board was then designed and developed as well as a radiation test program. The system was irradiated. This gave successful results, which confirmed aspects of the study and gave valuable insight into flash memory behaviour. To date, the board is still being used to test various flash devices for radiation-harsh environments. A memory protection unit (MPU) was conceptually designed and developed to morntor flash devices, increasing their reliability in radiation-harsh environments. This unit was designed for intended use onboard a micro-satellite. The chosen flash device for this study was the K9F1208XOA model from SAMSUNG. The MPU was designed to detect, maintain, mitigate and report radiation induced errors in this flash device. Most of the design was implemented in field programmable gate arrays and was realised using VHDL. Simulations were performed to verify the functionality of the design subsystems. These simulations showed that the various emulated errors were handled successfully by the MPU. A modular design methodology was followed, therefore allowing the chosen flash device to be replaced with any flash device, following a small reconfiguration. This also allows parts of the system to be duplicated to protect more than one device. / AFRIKAANSE OPSOMMING: 'n Studie is gemaak van" Flash" geheue en die foute daarop wat deur radiasie veroorsaak word. 'n Toetsbord is ontwerp en ontwikkel asook 'n radiasie toetsprogram waarna die stelsel bestraal is. Die resultate was suksesvol en het aspekte van die studie bevestig en belangrike insig gegee ten opsigte van "flash" komponente in radiasie intensiewe omgewmgs. 'n Geheue Beskermings Eenheid (GBE) is konseptueel ontwerp en ontwikkelom die "flash" komponente te monitor. Dit verhoog die betroubaarheid in radiasie intensiewe omgewings. Die eenheid was ontwerp met die oog om dit aan boord 'n mikro-satelliet te gebruik. Die gekose "flash" komponent vir die studie was die K9F1208XOA model van SAMSUNG. Die GBE is ontwerp om foute wat deur radiasie geïnduseer word in die "flash" komponent te identifiseer, herstel en reg te maak. Die grootste deel van die implementasie is gedoen in "field programmable gate arrays" and is gerealiseer deur gebruik te maak van VHDL. Simulasies is gedoen om die funksionaliteit van die ontwikkelde substelsels te verifieer. Hierdie simulasies het getoon dat die verskeie geëmuleerde foute suksesvol deur die GBE hanteer is. 'n Modulre ontwerpsmetodologie is gevolg sodat die gekose "flash" komponent deur enige ander flash komponent vervang kan word na gelang van 'n eenvoudige herkonfigurasie. Dit stelook dele van die sisteem in staat om gedupliseer te word om sodoende meer as een komponent te beskerm.

The past decade has witnessed the rapid growth of data in large-scale distributed storage systems. Triplication, a reliability mechanism with 3x storage overhead and adopted by large-scale distributed storage systems, introduces heavy storage cost as data amount in storage systems keep growing. Consequently, erasure codes have been introduced in many storage systems because they can provide a higher storage efficiency and fault tolerance than data replication. However, erasure coding has many performance degradation factors in both I/O and computation operations, resulting in great performance degradation in large-scale erasure-coded storage systems. In this thesis, we investigate how to eliminate some key performance issues in I/O and computation operations for applying erasure coding in large-scale storage systems. We also propose a prototype named ESetStore to improve the recovery performance of erasure-coded storage systems. We introduce our studies as follows. First, we study the encoding and decoding performance of the erasure coding, which can be a key bottleneck with the state-of-the-art disk I/O throughput and network bandwidth. We propose a graphics processing unit (GPU)-based implementation of erasure coding named G-CRS, which employs the Cauchy Reed-Solomon (CRS) code, to improve the encoding and decoding performance. To maximize the coding performance of G-CRS by fully utilizing the GPU computational power, we designed and implemented a set of optimization strategies. Our evaluation results demonstrated that G-CRS is 10 times faster than most of the other coding libraries. Second, we investigate the performance degradation introduced by intensive I/O operations in recovery for large-scale erasure-coded storage systems. To improve the recovery performance, we propose a data placement algorithm named ESet. We define a configurable parameter named overlapping factor for system administrators to easily achieve desirable recovery I/O parallelism. Our simulation results show that ESet can significantly improve the data recovery performance without violating the reliability requirement by distributing data and code blocks across different failure domains. Third, we take a look at the performance of applying coding techniques to in-memory storage. A reliable in-memory cache for key-value stores named R-Memcached is designed and proposed. This work can be served as a prelude of applying erasure coding to in-memory metadata storage. R-Memcached exploits coding techniques to achieve reliability, and can tolerate up to two node failures. Our experimental results show that R-Memcached can maintain very good latency and throughput performance even during the period of node failures. At last, we design and implement a prototype named ESetStore for erasure-coded storage systems. The ESetStore integrates our data placement algorithm ESet to bring fast data recovery for storage systems.