Scientific data centers comprised of high-powered computing equipment and large capacity disk storage systems consume considerable amount of energy. Dynamic power management techniques (DPM) are commonly used for saving energy in disk systems. These involve powering down disks that exhibit long idle periods and placing them in standby mode. A file request from a disk in standby mode will incur both energy and performance penalties as it takes energy (and time) to spin up the disk before it can serve a file. For this reason, DPM has to make decisions as to when to transition the disk into standby mode such that the energy saved is greater than the energy needed to spin it up again and the performance penalty is tolerable. The length of the idle period until the DPM decides to power down a disk is called idlenessthreshold. In this paper, we study both analytically and experimentally dynamic power management techniques that save energy subject to performance constraints on file access costs. Based on observed workloads of scientific applications and disk characteristics, we provide a methodology for determining file assignment to disks and computing idleness thresholds that result in significant improvements to the energy saved by existing DPMsolutions …

While initially a virtual institute, the driving force behind the creation of the DOE Joint Genome Institute in Walnut Creek, California in the Fall of 1999 was the Department of Energy's commitment to sequencing the human genome. With the publication in 2004 of a trio of manuscripts describing the finished 'DOE Human Chromosomes', the Institute successfully completed its human genome mission. In the time between the creation of the Department of Energy Joint Genome Institute (DOE JGI) and completion of the Human Genome Project, sequencing and its role in biology spread to fields extending far beyond what could be imagined when the Human Genome Project first began. Accordingly, the targets of the DOE JGI's sequencing activities changed, moving from a single human genome to the genomes of large numbers of microbes, plants, and other organisms, and the community of users of DOE JGI data similarly expanded and diversified. Transitioning into operating as a user facility, the DOE JGI modeled itself after other DOE user facilities, such as synchrotron light sources and supercomputer facilities, empowering the science of large numbers of investigators working in areas of relevance to energy and the environment. The JGI's approach to being a user facility is …