Sumeet Sobti

Considering the energy consumption of mobile storage alternatives

This paper is motivated by a simple question: what are the energy consumption characteristics of mobile storage alternatives? To answer this question, we are faced with a design space of multiple dimensions. Two important dimensions are the type of storage technologies and the type of file systems. In this paper, we explore some options along each of these two dimensions. We have constructed a logical-disk system, which can be configured to run on different storage technologies and to emulate the behavior of different file systems. As we explore these configuration options, we find that the energy behavior is determined by a complex interaction of three factors: the power management mechanism of the storage device, the distribution of idleness in the workload, and the file system strategies that attempt to exploit and bridge these first two factors.

Bridging the digital divide: storage media + postal network = generic high-bandwidth communication

Making high-bandwidth Internet access pervasively available to a large worldwide audience is a difficult challenge, especially in many developing regions. As we wait for the uncertain takeoff of technologies that promise to improve the situation, we propose to explore an approach that is potentially more easily realizable: the use of digital storage media transported by the postal system as a general digital communication mechanism. We shall call such a system a Postmanet. Compared to more conventional wide-area connectivity options, the Postmanet has several important advantages, including wide global reach, great bandwidth potential, low cost, and ease of incremental adoption. While the idea of sending digital content via the postal system is not a new one, none of the existing attempts have turned the postal system into a generic and transparent communication channel that not only can cater to a wide array of applications, but also effectively manage the many idiosyncrasies associated with using the postal system. In the proposed Postmanet, we see two recurring themes at many different levels of the system. One is the simultaneous exploitation of the Internet and the postal system so we can combine their latency and bandwidth advantages. The other is the exploitation of the abundant capacity and bandwidth of the Postmanet to improve its latency, cost, and reliability.

Network-Embedded Programmable Storage and Its Applications

We consider the utility of two key properties of network-embedded storage: programmability and network-awareness. We describe two extensive applications, whose performance and functionalities are significantly enhanced through innovative combination of the two properties. One is an incremental file-transfer system tailor-made for low-bandwidth conditions. The other is a “customizable” distributed file system that can assume very different personalities in different topological and workload environments. The applications show how both properties are necessary to exploit the full potential of network-embedded storage. We also discuss the requirements of a general infrastructure to support easy and effective access to network-embedded storage, and describe a prototype implementation of such an infrastructure.