We study cobordisms and cobordisms rel boundary of PL locally-flat disk knots Dn−2 ↪→ Dn. Any two disk knots are cobordant if the cobordisms are not required to fix the boundary sphere knots , and any two even-dimensional disk knots with isotopic boundary knots are cobordant rel boundary. However, the cobordism rel boundary theory of odd-dimensional disk knots is more subtle. Generalizing resul...

Configuring, installing, re-configuring, and re-installing disk drives can be time consuming. Understanding the physical disk and how UNIX file systems are laid out on disk drives can not only help an administrator troubleshoot problems, but can allow him/her to maximize the amount of disk space available. Standard formatting utilities tend to configure disks with similar geometry identically. ...

Title of Document: DISK DESIGN-SPACE EXPLORATION IN TERMS OF SYSTEM-LEVEL PERFORMANCE, POWER, AND ENERGY CONSUMPTION Nuengwong Tuaycharoen Doctor of Philosophy, 2006 Directed By: Associate Professor Bruce L. Jacob Department of Electrical and Computer Engineering University of Maryland, College Park To make the common case fast, most studies focus on the computation phase of applications in whi...

In the past decade, parallel disk systems have been highly scalable and able to alleviate the problem of disk I/O bottleneck, thereby being widely used to support data-intensive applications. Although a variety of parallel disk systems were developed, most existing disk systems lack a means to adaptively control the quality of security for dynamically changing workloads. We address this gap in ...

RAID5 tolerates single disk failures by exclusive-ORing (XORing) the blocks corresponding to a requested block on the failed disk to reconstruct it. This results in increased loads on surviving disks and degraded disk response times with respect to normal mode operation. Provided a spare disk is available, a rebuild process systematically reads successive disk tracks, XORs them to recreate lost...

Disk logging is a fundamental building block for faulttolerance system design because it captures a persistent snapshot of critical system state for subsequent recovery in the occurrence of failures. Logging typically is required to be synchronous to ensure absolute recoverability. Therefore speeding up synchronous disk write is critical to those fault tolerance systems that are based on disk l...

The birth environment of the Sun will have influenced the physical and chemical structure of the pre-solar nebula, including the attainable chemical complexity reached in the disk, important for prebiotic chemistry. The formation and distribution of complex organic molecules (COMs) in a disk around a T Tauri star is investigated for two scenarios: (i) an isolated disk, and (ii) a disk irradiate...