16,230 research outputs found
FLARE: A design environment for FLASH-based space applications
Designing a mass-memory device (i.e., a solid-state recorder) is one of the typical issues of mission-critical space system applications. Flash-memories could be used for this goal: a huge number of parameters and trade-offs need to be explored. Flash-memories are nonvolatile, shock-resistant and power-economic, but in turn have different drawback: e.g., their cost is higher than normal hard disk and the number of erasure cycles is bounded. Moreover space environment presents various issues especially because of radiations: different and quite often contrasting dimensions need to be explored during the design of a flash-memory based solid-state recorder. No systematic approach has so far been proposed to consider them all as a whole: as a consequence a novel design environment currently under development is aimed at supporting the design of flash-based mass-memory device for space application
How migrating 0.0001% of address space saves 12% of energy in hybrid storage
We present a simple, operating-\ud
system independent method to reduce the num-\ud
ber of seek operations and consequently reduce\ud
the energy consumption of a hybrid storage\ud
device consisting of a hard disk and a ďŹash\ud
memory. Trace-driven simulations show that\ud
migrating a tiny amount of the address space\ud
(0.0001%) from disk to ďŹash already results\ud
in a signiďŹcant storage energy reduction (12%)\ud
at virtually no extra cost. We show that the\ud
amount of energy saving depends on which part\ud
of the address space is migrated, and we present\ud
two indicators for this, namely sequentiality and\ud
request frequency. Our simulations show that\ud
both are suitable as criterion for energy-saving\ud
ďŹle placement methods in hybrid storage. We\ud
address potential wear problems in the ďŹash\ud
subsystem by presenting a simple way to pro-\ud
long its expected lifetime.\u
Flash-memories in Space Applications: Trends and Challenges
Nowadays space applications are provided with a processing power absolutely overcoming the one available just a few years ago. Typical mission-critical space system applications include also the issue of solid-state recorder(s). Flash-memories are nonvolatile, shock-resistant and power-economic, but in turn have different drawbacks. A solid-state recorder for space applications should satisfy many different constraints especially because of the issues related to radiations: proper countermeasures are needed, together with EDAC and testing techniques in order to improve the dependability of the whole system. Different and quite often contrasting dimensions need to be explored during the design of a flash-memory based solid- state recorder. In particular, we shall explore the most important flash-memory design dimensions and trade-offs to tackle during the design of flash-based hard disks for space application
Redundancy and Aging of Efficient Multidimensional MDS-Parity Protected Distributed Storage Systems
The effect of redundancy on the aging of an efficient Maximum Distance
Separable (MDS) parity--protected distributed storage system that consists of
multidimensional arrays of storage units is explored. In light of the
experimental evidences and survey data, this paper develops generalized
expressions for the reliability of array storage systems based on more
realistic time to failure distributions such as Weibull. For instance, a
distributed disk array system is considered in which the array components are
disseminated across the network and are subject to independent failure rates.
Based on such, generalized closed form hazard rate expressions are derived.
These expressions are extended to estimate the asymptotical reliability
behavior of large scale storage networks equipped with MDS parity-based
protection. Unlike previous studies, a generic hazard rate function is assumed,
a generic MDS code for parity generation is used, and an evaluation of the
implications of adjustable redundancy level for an efficient distributed
storage system is presented. Results of this study are applicable to any
erasure correction code as long as it is accompanied with a suitable structure
and an appropriate encoding/decoding algorithm such that the MDS property is
maintained.Comment: 11 pages, 6 figures, Accepted for publication in IEEE Transactions on
Device and Materials Reliability (TDMR), Nov. 201
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