The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Recent studies have identified disk storage systems as one of the major consumers of power in data centers. Many disk power management (DPM) schemes were suggested where the power consumed by disks is reduced by spinning them down during long idle periods. Spinning the disks down and up results in additional energy and response time costs. For that reason, DPM schemes are effective only if the disks...
It is anticipated that in the near future disk storage systems will surpass application servers and will become the primary consumer of power in the data centers. Shutting down of inactive disks is one of the more widespread solutions to save power consumption of disk systems. This solution involves spinning down or completely shutting off disks that exhibit long periods of inactivity and placing...
Datasets used in scientific and engineering applications are often modeled as dense multi-dimensional arrays. For very large datasets, the corresponding array models are typically stored out-of-core as array files. The array elements are mapped onto linear consecutive locations that correspond to the linear ordering of the multi-dimensional indices. Two conventional mappings used are the row-major...
Data analyses in scientific domains involve storage, retrieval, processing and visualization of large scale multidimensional datasets. The datasets incrementally grow by appending new data to the dataset without reorganizing the already allocated data storage. The datasets, typically modeled as k-dimensional arrays, are maintained in files where the array elements are allocated in a sequence of consecutive...
Bitmap indices have been widely used in scientific applications and commercial systems for processing complex, multi-dimensional queries where traditional tree-based indices would not work efficiently. A common approach for reducing the size of a bitmap index for high cardinality attributes is to group ranges of values of an attribute into bins and then build a bitmap for each bin rather than a bitmap...
In his paper Should the two-headed disk be greedy? - Yes, it should Hofri defined a greedy policy as follows. Assuming that the range of disk addresses is [0,1], a request at location x is served by the closest arm while the other arm jockeys to a new position, z, where z = (1)x or z =2 + x depending on whether x is larger or smaller than 1. Hofri proved that this policy minimizes the expected...
This paper addresses the problem of urgently needed data management techniques for efficiently retrieving requested subsets of large datasets from mass storage devices. This problem is especially critical for scientific investigators who need ready access to the large volume of data generated by large-scale supercomputer simulations and physical experiments as well as the automated collection of...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.