Mohammed G. Khatib

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The disk and the DRAM in a typical mobile system consume a significant fraction (up to 30%) of the total system energy. To save on storage energy, the DRAM should be small and the disk should be spun down for long periods of time. We show that this can be achieved for predominantly streaming workloads by connecting the disk to the DRAM via a large(More)
In computer systems, the storage hierarchy, composed of a disk drive and a DRAM, is responsible for a large portion of the total energy consumed. This work studies the energy merit of interposing flash memory as a streaming buffer between the disk drive and the DRAM. Doing so, we extend the spin-off period of the disk drive and cut down on the DRAM capacity(More)
Because of its small form factor, high capacity, and expected low cost, MEMS-based storage is a suitable storage technology for mobile systems. However, flash memory may outperform MEMS-based storage in terms of performance, and energy-efficiency. The problem is that MEMS-based storage devices have a large number (i.e., thousands) of heads, and to deliver(More)
MEMS-based storage devices should be energy efficient for deployment in mobile systems. Since MEMS-based storage devices have a moving media sled, they should be shut down during periods of inactivity. However, shutdown costs energy, limiting the applicability of aggressive shutdown decisions. The media sled in MEMS-based storage devices is suspended by(More)
Phase Change Memory (PCM) is emerging as an attractive alternative to Dynamic Random Access Memory (DRAM) in building data-intensive computing systems. PCM offers read/write performance asymmetry that makes it necessary to revisit the design of in-memory applications. In this paper, we focus on in-memory hash tables, a family of data structures with wide(More)
Because of its small form factor, high capacity, and expected low cost, MEMS-based storage is a suitable storage technology for mobile systems. MEMS-based storage devices should also be energy efficient for deployment in mobile systems. The problem is that MEMS-based storage devices are mechanical, and thus consume a large amount of energy when idle.(More)
We propose a tamper-evident storage system based on probe storage with a patterned magnetic medium. This medium supports normal read/write operations by outof-plane magnetisation of individual magnetic dots. We report on measurements showing that in principle the medium also supports a separate class of write-once operation that destroys the out-of-plane(More)
MEMS storage technology promises appealing features, such as ultrahigh density and low cost. To stay competitive, however, its performance must improve to fulfil the increasing I/O requirements in first-tier applications. Further, it must be energy-efficient. The maturity of MEMS techniques invites for a change in the basic single-medium architecture of(More)
Probes (or read/write heads) in MEMS-based storage devices are susceptible to wear. We study probe wear, and analyze the causes of probe uneven wear. We show that under real-world traces some probes can wear one order of magnitude faster than other probes leading to premature expiry of some probes. Premature expiry has severe consequences for the(More)
Power efficiency is pressing in today’s cloud systems. Datacenter architects are responding with various strategies, including capping the power available to computing systems. Throttling bandwidth has been proposed to cap the power usage of the disk drive. This work revisits throttling and addresses its shortcomings. We show that, contrary to the common(More)