4 research outputs found
Design of Soft Viterbi Algorithm Decoder Enhanced With Non-Transmittable Codewords for Storage Media
Viterbi Algorithm Decoder Enhanced with Non-transmittable Codewords is one of
the best decoding algorithm which effectively improves forward error correction
performance. HoweverViterbi decoder enhanced with NTCs is not yet designed to
work in storage media devices. Currently Reed Solomon (RS) Algorithm is almost
the dominant algorithm used in correcting error in storage media. Conversely,
recent studies show that there still exist low reliability of data in storage
media while the demand for storage media increases drastically. This study
proposes a design of the Soft Viterbi Algorithm decoder enhanced with
Non-transmittable Codewords (SVAD-NTCs) to be used in storage media for error
correction. Matlab simulation was used in this design in order to investigate
behavior and effectiveness of SVAD-NTCs in correcting errors in data retrieving
from storage media.Sample data of one million bits are randomly generated,
Additive White Gaussian Noise (AWGN) was used as data distortion model and
Binary Phase- Shift Keying (BPSK) was applied for simulation modulation.
Results show that,behaviors of SVAD-NTC performance increase as you increase
the NTCs, but beyond 6NTCs there is no significant change and SVAD-NTCs design
drastically reduce the total residual error from 216,878 of Reed Solomon to
23,900
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
An Empirical Study On the Recovery Speed of USB Flash Drives Utilizing Raid-5 Compared to HDDs and SSDs
Since their creation and implementation, storage drives have undergone and continue to undergo drastic changes in speed, size, and reliability. The original storage drives, known as hard disk drives (HDDs), are constructed using moving parts. The second modern type of storage drives, known as solid state drives (SSDs), are constructed using a series of silicon chips that utilize no moving parts. The third and most recent innovation in storage drives, known as USB flash drives (USBs), use only a single silicon chip to provide storage which grants them the smallest form factor of the three drive types.
This study compared these three types of storage devices with a RAID-5 drive redundancy configuration. A RAID-5 configuration logically joins three or more drives of a single type using either software or hardware, a situation in which both HDDs and SSDs are frequently placed. This research placed USBs in a similar configuration to compare their functional speeds within this arrangement with two similar configurations of HDDs and SSDs. These recorded speeds were then mathematically compared with the price of the drives to determine if USBs are a cost-effective alternative to HDDs and SSDs in the current marketplace. While the testing did not demonstrate consistent results with the selected batch of USB drives, the evolutionary trajectory of storage technology promises that such devices will eventually match their peers in processing capabilities