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<p>The past decade has seen wide availability of solid-state drives (SSDs) in settings ranging from personal computing to enterprise storage. Their success over the hard disks is driven by performance considerations and cost savings. Besides SSDs based on flash memory, there have been ongoing efforts in developing other non-volatile memory technologies such as phase-change memory and MRAM. All these technologies enable what we refer to as random-access block devices. Unlike hard disks, these devices have fast random accesses; on the other hand, their writes are more expensive than their reads. In this work, we study how to optimize database and storage algorithms for the I/O characteristics of random-access block devices. Specifically, we tackle the following three problems.</p><p>The first one is about permuting data out-of-core. While external merge sort is popular for implementing permutation on hard disks, it carries unnecessary overhead in storing and comparing keys. We propose more efficient algorithms for a useful class of permutations called Address-Digit Permutations on random-access block devices.</p><p>The second problem is concurrency control for indexes on SSDs. Various indexes have been proposed for these devices, but to make such indexes practical, we must address the issue of concurrency control. We propose a novel indexing and concurrency control scheme which allows concurrent accesses during ongoing index reorganizations, and does so with minimal memory and block-level locking.</p><p>The third problem concerns log-structured merge, a popular indexing technique well-suited to random-access block devices. We show how an intelligent partial merge policy, combined with a block-preserving merge procedure, can ­significantly lower write traffic while preserving other advantages of log-structured merge.</p> / Dissertation

The theme of the diploma thesis "Brno waterfront - rehabilitation of the Brno rivers and their surroundings" is creating an urban proposal in Brno, Zábrdovice, on the eastern waterfront of the Svitava river. The intention is to use the potential of the area and create the possibility of lucrative housing by river with a commercial ground floor, services, leisure time park with a multifunctional playground and easy direct access to the Svitava river. The studied location, has an area of 6.32 hectares andis defined mainly by the Zábrdovická Street and the Svitava River near the former Premonstratensian Monastery, which now serves as a Military Hospital. At present, the location has mainly low-floor industrial buildings with storage and expedition functions. The proposed buildings relate to existing buildings on the east and west banks of the Svitava River. They have the form of four to six storey blocks, which are characteristic for this area. The park connects to the revitalized eastern embankment of the river at the site of a new footbridgethat connects both rive sides and stairs. They provide space formeetings and relaxation, but also serve as a flood control in the event of a water inflow. Along the Svitava River there is a sidewalk with street alleyways and access to the river.