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Mirrored and Hybrid Disk Arrays: Organization, Scheduling, Reliability, and Performance [article]

Alexander Thomasian
2018 arXiv   pre-print
Shortest seek distance and affinity based routing both shorten seek time. Anticipatory arm placement places arms optimally to minimize the seek distance.  ...  Hybrid disk arrays which store XORed instead of replicated data tend to have a higher reliability than mirrored disks, but incur a higher overhead in updating data.  ...  Section 6 discusses analytic models to estimate seek distances and also cylinder remapping to reorganize data in mirrored disks to reduce seek distances.  ... 
arXiv:1801.08873v1 fatcat:epbfrk2ukberrnguq25joqyzua

RAID: high-performance, reliable secondary storage

Peter M. Chen, Edward K. Lee, Garth A. Gibson, Randy H. Katz, David A. Patterson
1994 ACM Computing Surveys  
Disk arrays were proposed in the 1980s as a way to use parallelism between multiple disks to improve aggregate I/O performance.  ...  It then discusses the two architectural techniques used in disk arrays: striping across multiple disks to improve performance and redundancy to improve reliability.  ...  Seek (random cylinder to cylinder) 11.0 ms Maximum Seek (full stroke seek) Data Transfer Rate 22.5 ms ≈ 4.6 MB/s -3 SCSI Disk Drive.  ... 
doi:10.1145/176979.176981 fatcat:5hb5vw56xrh2zo5cifiihoxlre

Modeling the performance and energy of storage arrays

Sankaran Sivathanu, Ling Liu, Cristian Ungureanu
2010 International Conference on Green Computing  
The key abstraction used in our analytical model is the run-lengtha single sequential run of requests at the disk level.  ...  We show that the performance and power predicted by the model under the migration and layout policies of PARAID accurately match the results of a detailed simulation of the system.  ...  ACKNOWLEDGEMENTS The first and second authors are partially supported by grants from NSF CISE NetSE program, CyberTrust program, an IBM SUR grant, an IBM faculty award, and a grant from Intel Research  ... 
doi:10.1109/greencomp.2010.5598308 dblp:conf/green/SivathanuLU10 fatcat:dnemztpumrhzxos7btj5amjl6e

The automatic improvement of locality in storage systems

Windsor W. Hsu, Alan Jay Smith, Honesty C. Young
2005 ACM Transactions on Computer Systems  
Disk I/O is increasingly the performance bottleneck in computer systems despite rapidly increasing disk data transfer rates.  ...  Since disk performance in practice is increasing by only about 8% per year [18], the benefit of ALIS may correspond to as much as several years of technological progress.  ...  Thanks are also owed to William Guthrie who shared with us his expertise in modeling disk drives, and to Ed Grochowski who provided the historical performance data for IBM disk drives.  ... 
doi:10.1145/1113574.1113577 fatcat:jcmhhs2q2jci7nxhpildq652mi

Dynamic and reversible remapping of network representations in an unchanging environment [article]

Isabel I.C. Low, Alex H Williams, Malcolm G Campbell, Scott W Linderman, Lisa M Giocomo
2020 bioRxiv   pre-print
This flexibility in neural coding is hypothesized to support navigation and memory by dividing sensory experience into unique contextual episodes.  ...  These remapping events were synchronized across hundreds of medial entorhinal neurons and correlated with changes in running speed.  ...  Specifically, k-means seeks to minimize equation (3) , Thus, if we view as the elements of an matrix, the rows of this matrix are constrained to be standard Cartesian basis vectors of -dimensional Euclidean  ... 
doi:10.1101/2020.10.05.326942 fatcat:aax7idcwlbdklgz6a3ge7p7bru

A gradient-based framework for maximizing mixing in binary fluids

M.F. Eggl, P.J. Schmid
2018 Journal of Computational Physics  
The stirrers are embedded in the computational domain by a Brinkman-penalization technique, and shape and path gradients for the stirrers are computed from the adjoint solution.  ...  A computational framework based on nonlinear direct-adjoint looping is presented for optimizing mixing strategies for binary fluid systems.  ...  Right column: Enforced minimum by mirroring the axis length across both cylinders at t = 8, 16, 24, 32.  ... 
doi:10.1016/j.jcp.2018.04.030 fatcat:mcl4wg6npravdb4352ab7547cm

Astrophotonics: astronomy and modern optics [article]

S. Minardi, R. Harris, L. Labadie
2020 arXiv   pre-print
We conclude by describing possible future developments in the field and their influence on astronomy.  ...  Much of the progress in Astronomy has been driven by instrumental developments, from the first telescopes to fiber fed spectrographs.  ...  Lasing media are typically inserted in an optical resonator, where light can be amplified by many orders of magnitude by passing it repeatedly in the amplifier by means of two mirrors.  ... 
arXiv:2003.12485v2 fatcat:bje62eojejbk3il5buv25ayjwu

Emerging display technologies - new systems and applications: from images to sensing, interaction and enhancement

2005 IEEE Proceedings. VR 2005. Virtual Reality, 2005.  
The only difference is that the connection jack that was to have been implanted in the back of our skulls is in fact turning out to be our collections of display and interface devices.  ...  As our culture and society become increasingly enveloped by computational technologies, we are quietly entering the world of a continuous cyberspace as real as that predicted by science fiction writers  ...  ACKNOWLEDGEMENTS The authors would like to especially thank Chris Ashworth for his early contributions in prototyping many of the ideas in this paper, and to our research colleagues Greg Welch and Marc  ... 
doi:10.1109/vr.2005.1492818 fatcat:cjrhq3hrlrgxvdh2jqw3gcblay

The Three‐dimensional Circumstellar Environment of SN 1987A

Ben E. K. Sugerman, Arlin P. S. Crotts, William E. Kunkel, Stephen R. Heathcote, Stephen S. Lawrence
2005 Astrophysical Journal Supplement Series  
Interior to this is a cylindrical hourglass, 1 ly in radius and 4 ly long, which connects to the Peanut by a thick equatorial disk.  ...  The nebulae are inclined 41 south and 8 east of the line of sight, slightly elliptical in cross section, and marginally offset west of the SN.  ...  As for the ellipse, we seek to find the six parameters that minimize the total distance from all transformed points to the z axis.  ... 
doi:10.1086/430408 fatcat:2m6o7uktwbhwfm7lswl5yqanye

Bluetooth Hacking: A Case Study

Dennis Browning, Gary Kessler
2009 Journal of Digital Forensics, Security and Law  
A Knowledge Index has been calculated by dividing the K&S mean by the I&E mean. This can be interpreted as follows.  ...  The data is inaccessible by the disk drive and the computer operating system.  ...  Certified Information Systems Security Professional (CISSP).  ... 
doi:10.15394/jdfsl.2009.1058 fatcat:cm7mvnadpzdthhitft5boixn5i

Matching Application Access Patterns to Storage Device Characteristics (CMU-PDL-03-109)

Jiri Schindler
2018
This dissertation (i) identifies specific features of disk drives, disk arrays, and MEMS-based storage devices not exploited by conventional systems, (ii) quantifies the potential performance gains these  ...  features offer, and (iii) demonstrates on three different implementations (FFS file system, database storage manager, and disk array logical volume manager) the benefits to the applications using these  ...  Seek times are measured for seeks of every distance between 1 and 10 cylinders, every 2nd distance up to 20 cylinders, every 5th distance up to 50 cylinders, every 10th distance up to 100 cylinders, every  ... 
doi:10.1184/r1/6619676 fatcat:ka5d5h5ftvcpnkrxdnktbg3lgq

39th European Conference on Visual Perception (ECVP) 2016 Barcelona

2016 Perception  
The metal mirrors made apparent distance and depth larger than the glass mirror.  ...  In this study, we investigated how the apparent distance to targets and the apparent depth between targets vary by mirror material.  ...  A clinical validation of the system was performed in a group of 250 patients.  ... 
doi:10.1177/0301006616671273 fatcat:el2dmsuk6zd25pedijucuexl5m

Designing computer systems with MEMS-based storage

Steven W. Schlosser
2018
Results from five application studies show these devices reduce application I/O stall times by 3-10X and improve overall application performance by 1.6-8.1X.  ...  This research explores the impact that several different MEMS-based storage designs will have on computer systems.  ...  Further, it can tolerate probe-tip failures simply by remapping the failed probe tip's data to a functional tip.  ... 
doi:10.1184/r1/6604802.v1 fatcat:amnfodhpxngvnfpk5lz4o2mlxu

CMB-S4 Science Case, Reference Design, and Project Plan [article]

Kevork Abazajian, Graeme Addison, Peter Adshead, Zeeshan Ahmed, Steven W. Allen, David Alonso, Marcelo Alvarez, Adam Anderson, Kam S. Arnold, Carlo Baccigalupi, Kathy Bailey, Denis Barkats (+190 others)
2019 arXiv   pre-print
This typically means that off-axis mirrors are used 18 .  ...  Gravity acts mostly in-plane for the secondary mirror, minimizing gravitational deformation.  ...  Re-use would likely involve a fee, upgrades to monitoring and control systems, and some additional testing and alignment to meet CMB-S4 requirements.  ... 
arXiv:1907.04473v1 fatcat:7lqitlzxefgizgekpzpccbdc3y

Particle hydrodynamics with tessellation techniques

Steffen Heß, Volker Springel
2010 Monthly notices of the Royal Astronomical Society  
We show that this eliminates spurious surface tension effects present in SPH and that play a role in suppressing certain fluid instabilities.  ...  We find that the new 'Voronoi Particle Hydrodynamics' described here produces comparable results than SPH in shocks, and better ones in turbulent regimes of pure hydrodynamical simulations.  ...  Also I would like to say that it is thanks to Volker Springel, that the work has been possible in this way.  ... 
doi:10.1111/j.1365-2966.2010.16892.x fatcat:nnt6k4msojeelfwtia4ff7lxuu
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