BORG: Block-reORGanization and Self-optimization in Storage Systems

This paper presents the design, implementation, and evaluation of BORG, a self-optimizing storage system that performs automatic block reorganization based on the observed I/O workload. BORG is motivated by three characteristics of I/O workloads: non-uniform access frequency distribution, temporal locality, and partial determinism in non-sequential accesses. To achieve its objective, BORG manages a small, dedicated partition on the disk drive, with the goal of servicing a majority of the I/O requests from within this partition with significantly reduced seek and rotational delays. BORG is transparent to the rest of the storage stack, including applications, file system(s), and I/O schedulers, thereby requiring no or minimal modification to storage stack implementations. We evaluated a Linux implementation of BORG using several real-world workloads, including individual user desktop environments, a web-server, a virtual machine monitor, and an SVN server. These experiments comprehensively demonstrate BORG’s effectiveness in improving I/O performance and its incurred resource overhead

Fluid Ontologies in the Search for MH370

This paper gives an account of the disappearance of Malaysian Airways Flight MH370 into the southern Indian Ocean in March 2014 and analyses the rare glimpses into remote ocean space this incident opened up. It follows the tenuous clues as to where the aeroplane might have come to rest after it disappeared from radar screens – seven satellite pings, hundreds of pieces of floating debris and six underwater sonic recordings – as ways of entering into and thinking about ocean space. The paper pays attention to and analyses this space on three registers – first, as a fluid, more-than-human materiality with particular properties and agencies; second, as a synthetic situation, a composite of informational bits and pieces scopically articulated and augmented; and third, as geopolitics, delineated by the protocols of international search and rescue. On all three registers – as matter, as data and as law – the ocean is shown to be ontologically fluid, a world defined by movement, flow and flux, posing intractable difficulties for human interactions with it

Behavior and Compositional Process in Georges Aperghis' "Luna Park"

Includes abstract and vita. --- Introduction -- Notational systems and strategies -- Collaborative composition -- Compositional process, vocal works -- Compositional process, ensemble works -- Conclusion.George Aperghis' compositional methodology in Luna Part (2011) is based upon an overarching conceptual framework, communicated through minimal notation means, for a collaborative process in which a work gradually coalesces over the course of development through interaction between composer and performers. The resulting artwork--an interdisciplinary performance of "composed theatre"--does not 'reside' in, or emerge from, traditional artifacts such as pre-notated musical scores, but rather exists as a collective memory within the specific community of musicians that has collaborated in its creation. Through development and rehearsal, a mode of performance materializes and is agreed upon that reflects the insterests and preferences of both composer and performers. The written document that initiates the compositional process and collaborative development is distinct from an indeterminate score--in that it is not, in itself, a "map" for an open-ended musical performance, but rather the catalyst of a process of compositional method that has not been comprehensively studied and is not easily codified as a system of organization or compositional technique, this study seeks to question fundamental assumptions that this method raises surrounding the function and role of a composer and score, as well as explore and evaluate those issues through the lens of the author's own experiences. How does Aperghis conceptualize composition and what is the impetus of a new work? What is the nature of his collaboration with performers, and is it possible for them to recreate this process autonomously without him? How is the work 'encoded' other than its manifestation in performance? Aperghis' Luna Park represents the confluence of strategies employed in previous works leading up to its creation

BORG: Block-reORGanization and Self-optimization in Storage Systems

Disk I/O is the primary performance bottleneck for a wide range of workloads due to the relatively large, mechanical seek and rotational delay overheads incurred during I/O operations. Current-day file systems that exclusively manage storage space on disk drives employ static data layouts and do not attempt to optimize for application access patterns. We argue that this lack of application awareness in operating system storage management is one of the key reasons for sub-optimal disk I/O performance. We present the design and implementation of BORG, a self-optimizing block storage layer that performs automatic block reorganization to optimize storage system performance, while remaining oblivious to the file system(s) and application layers above and the I/O scheduling and device driver layers below. BORG optimizes storage system performance in a continuous and online fashion by dynamically reorganizing disk data to best suit common disk access patterns. It successfully addresses the key requirements for a self-optimizing storage solution, incorporating accurate extraction and representation of disk access patterns, file system independence, modularization of storage stack layers, isolation of space management responsibilities, data consistency, online optimization capability, and overhead control. A Linux implementation of BORG demonstrates consistent improvements in disk I/O performance for a variety of workloads ranging from file servers and web servers to development workstations and even individual desktop applications, with acceptable overhead in other resource dimensions.

On the Development of a Confocal Rayleigh-Brillouin Microscope

This Note illustrates how a confocal microscope may be modified to conduct Rayleigh-Brillouin mapping experiments that yield very useful information on the mechanical properties of interfacial materials in small volume elements. While the modifications to the microscope are quite straightforward, they do entail significant changes in the optical design. The instrument described herein consists of an argon ion laser equipped with an actively stabilized intercavity étalon that serves as the excitation source for a modified Zeiss LSM 310 confocal laser scan microscope. The optics of the microscope were reconfigured to enable interfacing of the microscope with a tandem triple-pass Fabry-Pérot interferometer. This instrument enables three-dimensional Rayleigh-Brillouin spectral mapping of samples at micron spatial resolution. The performance of the instrument and its ability to perform both lateral and depth scans of the acoustic phononvelocity and, hence, the longitudinal modulus across bonded polymer/polymer and polymer/ceramic interfaces are illustrated and discussed

On the Development of a Confocal Rayleigh-Brillouin Microscope

This Note illustrates how a confocal microscope may be modified to conduct Rayleigh-Brillouin mapping experiments that yield very useful information on the mechanical properties of interfacial materials in small volume elements. While the modifications to the microscope are quite straightforward, they do entail significant changes in the optical design. The instrument described herein consists of an argon ion laser equipped with an actively stabilized intercavity étalon that serves as the excitation source for a modified Zeiss LSM 310 confocal laser scan microscope. The optics of the microscope were reconfigured to enable interfacing of the microscope with a tandem triple-pass Fabry-Pérot interferometer. This instrument enables three-dimensional Rayleigh-Brillouin spectral mapping of samples at micron spatial resolution. The performance of the instrument and its ability to perform both lateral and depth scans of the acoustic phononvelocity and, hence, the longitudinal modulus across bonded polymer/polymer and polymer/ceramic interfaces are illustrated and discussed

BORG: Block-reORGanization and Self-optimization in Storage Systems

This paper presents the design, implementation, and evaluation of BORG, a self-optimizing storage system that performs automatic block reorganization based on the observed I/O workload. BORG is motivated by three characteristics of I/O workloads: non-uniform access frequency distribution, temporal locality, and partial determinism in non-sequential accesses. To achieve its objective, BORG manages a small, dedicated partition on the disk drive, with the goal of servicing a majority of the I/O requests from within this partition with significantly reduced seek and rotational delays. BORG is transparent to the rest of the storage stack, including applications, file system(s), and I/O schedulers, thereby requiring no or minimal modification to storage stack implementations. We evaluated a Linux implementation of BORG using several real-world workloads, including individual user desktop environments, a web-server, a virtual machine monitor, and an SVN server. These experiments comprehensively demonstrate BORG’s effectiveness in improving I/O performance and its incurred resource overhead.