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This PDF file contains the front matter associated with SPIE Proceedings Volume 7517, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.
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Photonics and Optoelectronics Meetings (POEM) 2009: Optical Storage and New Storage Technologies
This paper presents a new fast video watermarking scheme in spatial domain for embedded device identity verification.
A binary watermark signal, which is produced by the identity of the embedded device such as the disc video player, is
permutated using sequence numbers generated by a secret key. And then it is encoded by Gray code. Each bit of the
binary encoded watermark is embedded four times in different positions, by modifying the intensities of a nonoverlapping
block of 8*8 of the blue component of the frames in host video. In watermarking extract scheme, the frame
of the watermarked video and the original video are decoded to images. And the intensities of a block of 8*8 of all
components of the frame images in the watermarked and the original video are compared to calculate the probability of
detecting '0' or '1' for extracting binary watermark. Both the embedding and the extraction of watermarks are done in the
spatial domain, so the computational cost is low. Then the digital watermark with the identity information is embedded
in real time to the video image when the embedded devices play their videos. Experimental results show that the
algorithm has obvious low complexity, and the strong robustness against distortion, deleting, and cropping operations.
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With the popularity of Saas (Software as a service), backup service has becoming a hot topic of storage
application. Due to the numerous backup users, how to reduce the massive data load is a key problem for system
designer. Data compression provides a good solution. Traditional data compression application used to adopt a
single method, which has limitations in some respects. For example data stream compression can only realize
intra-file compression, de-duplication is used to eliminate inter-file redundant data, compression efficiency cannot
meet the need of backup service software. This paper proposes a novel hybrid compression approach, which
includes two levels: global compression and block compression. The former can eliminate redundant inter-file
copies across different users, the latter adopts data stream compression technology to realize intra-file
de-duplication. Several compressing algorithms were adopted to measure the compression ratio and CPU time.
Adaptability using different algorithm in certain situation is also analyzed. The performance analysis shows that
great improvement is made through the hybrid compression policy.
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A new photochromic diarylethene bearing thiazole and a six-membered aryl unit 1-(2, 4-dimethyl-5-thiazolyl)
-2-(2-methylphenyl)perfluorocyclopentene has been synthesized. Its properties, including photochromism and
fluorescence were investigated in detail. It underwent reversible cyclization and cycloreversion reactions upon
alternating irradiation with UV and visible light both in solution and in PMMA film. The results showed that this
compound exhibited reversible photochromism, changing from colorless to yellow after irradiation with UV light both in
solution and in PMMA amorphous film. In hexane, compound 1a exhibited an absorption peak at 293 nm, upon
irradiation with 254 nm light, a new visible absorption band centered at 449 nm emerged while the original peak at 293
nm decreased. In PMMA amorphous film, diarylethene 1a also showed good photochromism as similar to that in
solution .Upon irradiation with 313 nm light, the absorption maxima was observed at 462 nm. Diarylethene 1 also
exhibited good fluorescent switching both in solution and in PMMA flim upon alternating irradiation with UV and
visible light. At last, polarization optical recording using diarylethene 1b as recording medium was carried out
successfully.
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Resolution and focal depth are very important parameters in optical data storage systems, and have attracted much
attention. In this article, focusing properties of concentric two-zone cylindrical vector beam are investigated theoretically
by means of vector diffraction theory. The phase shift of the center zone and outer annular zone are different. Simulation
results show that the focal pattern can be altered considerably by adjusting the radius of dividing circle between the two
concentric portions and the phase shift of each zone. For certain phase shifts for these two zone, focal spot broadens
along optical axis with increasing radius, and splits into two peaks, and then combine back into one peak again. In this
evolution process, some novel focal pattern may come into being. For certain geometrical parameter and phase shift, the
focal spot shrinks, which means superresolution effect appears, and at the same time, focal depth can also be widened,
high focal depth companies with resolution, which is very useful in optical data storage systems.
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Tellurium oxide (TeOx) thin films have been prepared by rf reactively sputtering deposition by using a tellurium target
under Ar-O2 gas mixture. The effect of O2/Ar ratio on the structure and optical properties was investigated by XRD,
FTIR and optical transmission measurement. With increasing the O2/Ar ratio the optical band gap of thin films increased
from 0.59eV to 0.87eV, but the Urbach energy firstly decreased, then increased. After UV illumination, the blue and red
shifts of absorption edge were observed. And the annealing of
as-deposited films also was done. It was proposed that the
blue and red shifts may be related with the Urbach energy. All the results can be attributed to the rearrangement of
bonding network with the variation of stoichiometry of tellurium oxide films.
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A unsymmetrical photochromic diarylethene,
1-[2-methyl-5-(4-chlorophenyl)-3-thienyl]-2
-(2-cyano-1,
5-dimethyl-4-pyrryl)hexafluorocyclopentene (1a), was synthesized, and its photochromic and fluorescent properties were
also investigated. The results showed that this compound exhibited reversible photochromism, changing from colorless
to blue after irradiation with UV light both in solution and in PMMA amorphous film. The open-ring isomer of the
diarylethene 1 exhibited relatively strong fluorescence at 412 nm in hexane solution (5×10-5 mol/L) and 417 nm in
PMMA amorphous film when excited at 320 nm. The fluorescence intensity decreased along with the photochromism
upon irradiation with 297 nm light and its closed-ring isomer showed almost no fluorescence. The fluorescence spectra
of diarylethene 1a depended on the concentration and the polarity of the solvent. Using diarylethene 1 as recording
medium, polarization holographic optical recording was carried out successfully.
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As a result of Nand flash memory being widely used as storage medium, solid-state disk has inherited the intrinsic
hardware features from the Nand flash memory. Unlike standard block access devices, the flash memory media needs to
be erased before program operations and the block endurance is limited. Therefore distributing erasure operations evenly
across the whole flash memory blocks is a hot research issue for designing solid-state disk. In this pager, an efficient
wear-leveling algorithm is put forward. The basic idea is that: for each writing operation, new data will be written to the
block which have a minimum number of erasure cycles in the whole erased blocks, and the block storing static data and
with relatively small number of erasure cycles will be forced to move their data to the erased block with high number of
erasure cycles. The infrequent updated data will stay in old block until wear-leveling takes effect again. In addition, an
efficient page mapping table technology is also proposed; this technology can reduce the average read response time.
Extensive simulation and comparison were performed, and the results show that the provided algorithm, needing small
memory space can make all the blocks of flash having the average number of erasure cycles, which significantly
improves the lifespan of solid-state disk by more than 70% and reduces extra block erasure cycles and extra live-data
coping.
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Biochip is a kind of nano/microfluidic chip based on biology system. All advanced microfluidic are moving into small
micro-meter and nano-meter scale and need a low cost and high production manufacturing method. The history and
situation of biochips as well as the situation of optical storage industry, including the difficulties which producers face to,
are surveyed. The advantages and disadvantages for the fabricating method of biochip based on CD/DVD production
line are put forward. Once the low cost technology is developed, it will be able to speed up biotech research as well as
revival of optical storage industry and make use of the unemployed optical instruments.
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In this article, the focal properties of cylindrically polarized beams through a high numerical aperture parabolic mirror
are numerically investigated. The vector field distributions within the focal region for cylindrically polarized beams are
calculated by using the Richards-Wolf vectorial diffraction theory. It shows that the three-dimensional intensity distributions in the vicinity of the focus is dependent on the polarization rotation angle, topological charge and numerical aperture value. Additionally, some interesting focal volume structures, such as adjustably confined flat-topped focus,
doughnut focal hole can be obtained by controlling polarization rotator angle. The tightly focused cylindrically polarized beams by a high numerical aperture parabolic mirror have possible applications in particle acceleration, optical
trapping and manipulating, single molecule imaging and high resolution imaging microscopy, et al.
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Hydrophilic SiO2-nanoperticals dispersed polyvinyl alcohol /acrylamide (PVA/AA)
binder-based volume holographic recording photoloymers are fabricated. In this photopolymer,
monomer-nanoparticle counter diffusion plays a fundamental and key role in hologram formation. The
experimental results indicate that nearly 20% increase of diffraction efficiency together with refractive
index modulation photopolymer films containing SiO2-nanoperticals contrast with traditional samples.
The optimum concentration of SiO2-nanoperticals and the origin of diffraction efficiency enhancement
are investigated. It is shown that the nanoparticles are uniformly dispersed in the sol-gel photopolymer
and significantly influence on the grating formation. Additionally, the incorporation of inorganic
nanoparticles into photopolymer leads to the substantive suppression of the volume shrinkage during
holographic exposure.
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A new unsymmetrical photochromic diarylethene compound,
[1-(2-methyl-5-phenyl-3-thienyl),2-(2-methyl-5-(2-pyridyl)-3-thienyl)]perfluorocyclopentene (1a), was synthesized and its photochemical properties, such as
photochromism and kinetics in solution as well as in PMMA amorphous film, electrochemical properties and optical
strorage properties were investigated in detail. The results showed that the cyclization/cycloreversion process of the
compound was determined to be the zeroth/first order reaction, the electrochemical properties suggests that the
diarylethene derivative can be used as an electrochemical switch and electrochemistry data storage, and the optical
propertis can be potential use for data storage.
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This paper presents the profile measurement method for recording marks in signal waveform modulation multilevel
(SWM) read-only disc. In SWM disc, multilevel is realized with the combined varying size and position of inserted subpit/
sub-land in an original recording land/pit. The micro-patterns of the recording marks are key identifier for level of
run-lengths. In mastering process, the mark profile is shaped with timing duration variation of the power of laser beam
recorder (LBR). To form ideal SWM recording pit microstructure, atomic force microscope (AFM) is used to measure
the pit profile, which is feedback and used to adjust the writing strategy. The measured parameters including depth,
height and position, etc. 6T land and pit are selected as examples to describe the relationship between the variation of
these parameters and levels of run-lengths. The recording symbol microstructures of DVD and signal amplitude
modulation (SAM) multilevel optical disc are also measured with AFM, which are compared with the mark profile of
SWM disc. The experimental results show that the AFM measurement for SWM recording marks is an effective method.
These quantitative measurement results provide theoretical basis for SWM stamper disc manufacturing process.
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The present study is aimed to develop a nanobiomedicine
crystal-inspired optical quantum bit (qubit) storage system, as
one candidate of potentially promising solutions to the nanofabrication problem, by a bottom-up approach of chemical or
physical forces operating at a nanometer scale, to self-assemble 0.1nm~10nm basic units into a large "vertical" storage
architecture for simultaneously computing several qubits. The state of an optical qubit may be measured in a momentum
space by using laser micro-photoluminescence spectrum (Laser micro-PL spectrum) in combination with the Gaussian
non-linear function fit of optical wavelengths and optical intensities and twice faster Fourier transformations of
photoluminescence spectra at time and frequency domains. All architectures of self-assembled nanobiomedicine may be
probed by conducting atomic force microscopy (C-AFM) in three dimensions (x, y, z axes) with a powerfully spatial
resolution at sub-angstrom. The reproducible results of optical qubit measurements in self-assembled nanobiomedicine
crystals more than six times by laser micro-PL spectra for one nanobiomedicine crystal sample were acquired, as shown
in average values of wavelengths and intensities with standard deviations in laser micro-PL spectra. It is concluded that
the nanobiomedicine crystal-inspired optical qubit storage is emerging as a new solid state storage system.
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We studied some factors affecting the properties relevant to nonvolatile hologram storage by using two-color
recording scheme in In(0,1mol.%):Fe:Cu:LiNbO3 crystals. Two-color recording is achieved by use of 488nm blue light
acts as the sensitized light and 633nm red light acts as the recording light. First, the effect of In3+ doping on the
nonvolatile photorefractive properties was investigated experimentally. Next, the influences of the pre-illumination
processing, the red-to-blue intensity ratio as well as the oxidation-reduction treatments on the nonvolatile photorefractive
properties of In(1mol.%):Fe:Cu:LiNbO3 crystal were studied in detail.
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A novel constant linear velocity (CLV) control method employing sync pattern detection has been developed for the
multi-level run-length limited read-only disc. In the proposed method, the sync pattern is special designed and inserted in
the RF signal to detect the velocity error of the spindle. The differentiation method is adopted to detect the sync pattern
from the RF signal and is more easy and accurate than using the threshold level slicer. By using the proposed CLV
method, the spindle works robust in the CLV mode and the velocity error of the spindle can be suppressed less than
0.3%. The experimental result shows the novel CLV control method for the ML-RLL read-only disc is practicability.
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A nickel(II) hydrazone complex was synthesized in order to obtain a suitable optical recording medium for the new
generation recordable blu-ray disk. Smooth thin films of the nickel(II) hydrazone complex were prepared by using the
spin-coating method. Absorption and reflectance spectra of the thin films were evaluated in the wavelength 300-700 nm.
Thermal properties of the nickel(II) complex were investigated by thermogravimetry (TG) and differential scanning
calorimetry (DSC). Optical constants (complex refractive indices N=n+ik) and thickness of the thin film, prepared on
single-crystal silicon substrate, were investigated on a rotating analyzer-polarizer scanning ellipsometer in the
wavelength 285-705 nm. In addition, in order to examine its possible use as a blu-ray recording medium, the spin-coated
film of the nickel(II) complex was prepared on K9 glass substrate with a silver reflective layer, and was studied by static
optical recording testing system with a 406.7 nm laser. It is found that the absorption spectra of the thin film has an
strong absorption band in the wavelength region 360-420 nm and a moderate absorbance at the 405 nm side, which
indicates that the absorption of the film is well matched with the laser wavelength of the 405 nm. The reflectance spectra
show that a high reflectivity of the thin film at 405 nm wavelength can be obtained by an optimum film thickness and an
appropriate metal reflective layer. The thin film of the nickel(II) complex gives a high n value of 1.62 and a low k value
of 0.33, corresponding to the wavelength of the blue laser of 405 nm. Measurements of the thermal properties show that
the nickel(II) complex holds a high thermal stability (~ 300 °C) and a sharp weight loss which are helpful to fabricate a
small and sharp recording mark edge. The results of the static optical recording test, using the nickel(II) complex thin
film as the recording layer, demonstrate that high reflectivity contrast (>50 %) can be obtained at an optimum laser
writing power and pulse width. In addition, the recording marks are durable even after 20000 times readout. These
preliminary results indicate that the nickel(II) hydrazone complex has great potential application for high-density discrecordable
system at wavelength of the 405 nm.
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A novel photochromic diarylethene, 1-(2-ethyl-3-benzothienyl)-2-(
2-methoxylphenyl)perfluorocyclopentene(1a) was
synthesized and its photochromic and fluorescent properties were investigated. This compound showed good
photochromism both in solution and in PMMA amorphous film. In hexane solution, the open-ring isomer of the
diarylethene 1 exhibited relatively strong fluorescence at 363 nm when excited at 327 nm. This new photochromic
compound also exhibited remarkable fluorescence switching in the solid state. Using diarylethene 1b/PMMA film as
recording medium, the evaluation of potential of photochromic diarylethene as a polarization medium by recording and
reading in a real-time operation was investigated.The results demonstrated that the diarylethene compound had attractive
properties for high density optical storage.
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A new symmetrical photochromic diarylethene,
1-[2-methyl-5-(3-cyanophenyl)-3-thienyl]-2-[
(2-trifluoromethylphenyl)] perfluorocyclopentene(1a), was synthesized, and its photochromic properties were investigated
in detail. The compound exhibited good photochromism both in solution and in PMMA film with alternating irradiation
by UV/VIS light, and the maxima absorption of its closed-ring isomer 1b are 542 and 553 nm, respectively. Especially,
the cyclic voltammetry tests demonstrated that the colorless open-ring isomers were assigned to the unique oxidation
process, but the color closed-ring isomers of the compounds were assigned to two oxidation processes. Using
diarylethene 1b/PMMA film as recording medium and a He-Ne laser (633 nm) for recording and readout, three types of
polarization holographic optical recording were performed perfectly. The experiment demonstrates that diarylethene
/PMMA films can be used to hide and display two differently polarized patterns, which may be applied in optical
recording and camouflage technology.
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Zr:Fe:LiNbO3 crystals with various of [Li]/[Nb] ratios were grown by Czochralski technique from melts having
compositions varying between 46-58 mol% Li2O. The compositions of the growth crystals were determined by the
inductively coupled plasma technique (ICP-AES). The defect structures were analyzed by UV-vis spectroscopy. The
photorefractive properties of the Zr:Fe:LiNbO3 were investigated by using two-beam coupling experiment. The results
showed that as the [Li]/[Nb] ratio increased, the diffraction efficiency decreased, but photorefractive sensitivity
increased , and the response time decreased.
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Continuous increment of magnetic recording density requires the realization of necessary
signal-to-noise-ratio (SNR) with less number of grains per bit, a fundamental limit in this approach is
that the thermal effect for continued scaling would cause spontaneous magnetization reversal of
individual grains, which would result in loss of recorded data. Patterned media can significantly
reduce the grain number per bit at the required SNR by its good pattern shape uniformity.
This paper focused on the recording performance evaluation of bit patterned media. Using
Karlqvist head and single pole head, the SNR of oriented continuous media (CM), patterned
longitudinal media (PLM) and perpendicular patterned media (PPM) were investigated via finite
element method. It is found that the SNR of PLM is approximately 20% higher than that of CM, with
the same anisotropy orientation distribution. At each areal density, the SNR of PPM remains the highest
before the areal density reaches 800Gbit/in2.
By comparing the simulation results of SNR of patterned longitudinal media at different bit aspect
ratio, it is indicated that with the dot size dispersion increase, the perfect media with the highest SNR
was also the most susceptible to size variation. These dispersions significantly increase down-track
noise and the effect was greatest at high linear densities where the signal was low. The effect of grain
diameter on magnetization variance of both PLM and PPM were also investigated.
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To improve the resolving power of high-density optical data storage, the superresolving technology regarding
Gaussian beam was investigated in detail and the related superresolving filters were given. These designed
superresolving filters were applied into the optical pick-up system and the mastering system to improve the resolution.
Two different structures of superresolving optical pick-up system were presented. Each of them is of great practical
benefits. Also after a detailed investigation, the structure of superresolving mastering system was fixed. The intensity
distribution on the focusing plane was simulated with the software ZEMAX. The simulated results validate that our
designed superresolving filter regarding Gaussian beam is more accurate than those based on uniform-amplitude incident
beam in practical application.
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The reversible molecule switching of an assymmetrical photochromic diarylethene
1-(2-methyl-5-phenyl-3-thienyl-2-[2-methy1-5-(4-ethoxylpheny1)
-3-thieny1]perfluorocyelopentene (MPTMEPTF6) has been prepared for
the examination of photo-switching, fluorescence switching. The photochromism properties of MPTMEPTF6
diarylethene show good photochromism in hexane and in PMMA amorphous film. Steady state fluorescence studies
indicated that MPTMEPTF6 diarylethene is higher fluorescent in the open-ring isomer, but there almost no
fluorescence in the closed-ring isomer in PMMA amorphous film. The diarylethene MPTMEPTF6 has promising
application for photo-switching, fluorescence-switching which can use for data storage.
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The local field enhancement generates in the vicinity of the tip which has approached to surface plasmon resonance (SPR)
region of the sample. The power of the local field enhancement could be utilized to pattern the sample, and this new
lithography method is called probe inducing surface plasmon resonance nanolithography (PSPRN). Owing to the high
energy density of local field enhancement and super-diffraction limiting character, PSPRN has the advantages of low
power consumption and high resolution. The influence of various film parameters on SPR was simulated by eigenmatrix
method in this paper. Through analysis and by comparison, glass ZF6, silver (Ag), silicon dioxide (SiO2) and silver oxide
(AgOx) were selected as the materials for prism, metal layers, protecting layers and recoding layers respectively. A
PSPRN experiment was implemented on an atomic force microscope (AFM). In the experiment, samples with
single-layer, double-layer, and three-layer structures were researched. Holes of 100nm / 18nm, 75nm / 7nm and 195nm /
7.5nm (diameter/depth) were written into the three structures respectively. However, the result was not ideal with
three-layer structure. The influence of diverse parameters on the size of lithography point has been analyzed, which
could help providing the theory basis for improving experiment equipment.
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A new unsymmetrical photochromic diarylethene
1-[(2-methyl-5-(2-cyanophenyl)-3-thienyl)
]- 2 - [ ( 2 - trifluoromethylphenyl) ] perfluoroscyclopentene (1a) was
synthesized, its photochromic properties were examined, the
result indicated that the Diarylethene 1a changed the color from colorless to red upon irradiation with 313 nm UV light, in
which absorption maxima were observed at 541 and 548 nm in hexane and PMMA film, respectively. The the
photochromic reaction kinetics indicated that the cyclization processes of 1 belong to the zeroth order reaction and the
cycloreversion process belong to the first order reaction. This new photochromic system also exhibited remarkable
fluorescence switching in hexane solution and this new photochromic system also exhibited remarkable optical storage
character.
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A novel photochromic diarylethene bearing a six-membered aryl unit, 1-[2-methyl-5-(3-methoxylphenyl)-3-thienyl]-2-
(2-cyanophenyl)perfluorocyclopentene (1a), was synthesized and its photochromic and electrochemical properties were
investigated. Diarylethene 1a changed the color from colorless to magenta upon irradiation with 297 nm UV light, in
which absorption maxima were observed at 545 nm in hexane and at 551 nm in PMMA film, respectively. The results
also showed that the cyclization/cycloreversion process of the compound was determined to be the zeroth/first order
reaction, and the electrochemcial switching property can be potential use for electrochemistry data storage. Finally,
photo-mode rewritable optical storage using 1a was performed. The images demonstrated that the compound as optical
storage material was very sensitive responding to 633 nm recording laser, and the recorded-signals were provided with
high S/N ratio.
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Crystallization dynamics of as-deposited amorphous AgInSbTe and SiSb thin films induced by picosecond laser pulses
with different fluences were studied using time-resolved reflectivity measurements. The transient phase change process
during crystallization was discussed and compared.
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In this paper, we investigate data layout schemes and their impact on system reliability in a petabyte scale storage system
built from thousands of Object-Based Storage Devices. We delve in two underlying data layout schemes: RAID 5 and
RAID 5 mirroring. To accelerate data reconstruction, Fast Mirroring Copy is employed where the reconstructed objects
are stored on different OBSDs throughout the system. In order to improve the system reliability, SMART Reliability
Mechanism (SRM) is introduced for enhancing the reliability in very large-scale storage system. Analysis results show
that they can be used to assure the reliability of data storage and efficiently utilize the disk resource while exert minimum
impact on the whole systems performance.
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Data is the core resource of the information system, so that data corruption is one of the key
problems which are on top of the radar screen of most information system administrators.
Continuous Data Protection (CDP) technologies help them deal with data corruption by
providing timely recovery to any point-in-time. But in this CDP process, the CDP system
needs record every data changes, and then the extra system I/O operations increase greatly,
the performance of information systems will be lower and the system cannot provide the best
service. This paper discusses a method based buffer chains that can reduce the extra I/O
operations from the disk. We have presented an implementation in the Linux kernel which
provides continuous data protection service with higher performance under some buffer
chains strategy.
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With the networked storage becomes a tendency of data storing, the data stored on storage device gradually
becomes the major goal of the malicious attackers, and the storage system becomes the final defense line to safeguard
data security. To strengthen the confidentiality of data, this paper designed a new cryptographic read/write flow for
networked storage system. On the base of the optimized data read/write flow, we implemented a Kernel-based
Cryptographic File System (short for KCFS). The cryptographic file system can overcome the inconvenience of encryption application and the low efficiency of user-level encryption file system, e.g CFS, so as to realize the encryption/decryption function at the kernel-level file system, providing the upper-level application a transparent storage
space. Additionally, the data is stored in cipher-text mode, so can protect the stored data from illegal exposure. In the
comparative experiment, the transferring rate of NFS+KCFS reduces between 9.2% and 13.2% relative to NFS, and the transferring rate of NFS+CFS reduces between 18.6% and 30.1%. The experiment shows that KCFS can reach better read/write performance compared to user-level encryption file system.
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An object-based storage system - integrating advantages of both NAS and SAN - can be applied in large-capacity, lowcost
and large-scale storage systems built from commodity disk devices. The continuous data protection or CDP is a
well-known technique that continuously captures or tracks data modifications and stores changes independent of primary
data, enabling data recovery - from any point in the past. An efficient file system optimized for CDP plays an important
role in object-based storage systems. In this paper, concurrent processes during data backup and data recovery operations
are discussed in details. To fully take the advantage of distributed system architectures, we make the concurrent data
operations as far as possible during read, write, and recovery processes. A new backup data object placement strategy is
present to work in coordination with a replica strategy in
object-based distributed file systems. Backup data object can be
placed in other object storage servers (or OSS for short) instead of the OSS where the original data is residing, when the
backup data object matches certain conditions. For data recovery, we make the related OSSes to concurrently perform
data object movement. All these strategies can efficiently reduce system response times.
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Nowadays P2P systems have become increasingly popular for object distribution and file sharing, and the majority of
Internet traffic is generated by P2P file sharing applications. However, those applications usually ignored the underlying
proximity of physical nodes and regionalization of file accessing. As a result, they generate a large amount of
unnecessary interdomain transit traffic and increase response latency. In this paper, we proposed a new traffic control
approach to enhance p2p traffic locality and reduce the cross-group transfer. Using analysis, we show that the method
substantially improves node transfer efficiency and significantly reduces file access latency compared with native P2P
applications.
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Light rare earth-heavy rare earth-transition metal films (LRE-HRE-TM)have large saturation magnetization (Ms) and are
the promising media for hybrid recording. In this paper, Nd(Tb,Dy)Co/Cr films with perpendicular magnetic anisotropy
were successfully fabricated onto glass substrate by RF magnetron sputtering and the effects of sputtering technology
parameters and Nd substitution for HRE atoms on the magnetic properties were investigated. It was found that when the
sputtering power and sputtering time are 250W and 4min, respectively, the magnetic properties of Nd(Tb,Dy)Co/Cr
films obtain optimization, perpendicular coercivity, Ms and remanence square ratio(S) of NdTbCo/Cr film reach 3.8kOe,
247emu/cm3 and 0.801, respectively. With the increasing of Nd concentration, Ms increases, while the coercivity (Hc)and
the temperature stability of magnetic properties decrease distinctly. These results can be explained by the ferri-magnetic
structure of the RE-TM alloy.
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In this paper, a heat transfer model has been developed and employs method of Green function (heat source
method) to calculate the temperature distribution in the magnetic film by using ATM tip transferring heat. The
results indicate that the temperature in a magnetic film is relative to the diameter of the tip and the power of the
laser pulse. Specifically, the power of laser pulse has a critical point threshold in hybrid recording by using
this method.
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Object-based storage system integrates advantage of both NAS and SAN, can be applied in large-capacity, low-cost and
large-scale storage systems which are built from commodity devices. Continuous data protection (CDP) is a
methodology that continuously captures or tracks data modifications and stores changes independent of the primary data,
enabling recovery points from any point in the past. An efficient file system optimized for CDP is needed to provide
CDP feature in object-based storage system. In this thesis, a new metadata management method is present. All necessary
meta data information are recorded when changes happened to file system. We have a journal-like data placement
algorithm to store these metadata. Secondly, this metadata management method provides both CDP feature and Object-based
feature. Two type write operations are analyzed to reduce storage space consumption. Object-based data allocation
algorithm can take the advantage of distributed file system to concurrently process CDP operations over storage nodes.
Thirdly, history revisions and recovery operations are discussed. Finally, the experiment test result is present and
analyzed.
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Recently, the research about deduplication technology is focus on how to save the disk space and decrease the chunking
index table's size but not performance analysis when this technology is integrated into the storage system. In this paper,
we present the classification of various deduplication technologies for storage and compare these different categories
then develop the architecture and process flow for the online storage service. The analytical model is developed to
description and calculation of storage performance, including the deduplication ratio, system throughput and energy
savings. The results analyzed on the model are encouraging, and indicating that the model provides the accurate
performance.
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FCoE (Fibre Channel over Ethernet) is a newly emerging storage networking protocol, which encapsulates Fibre Channel frames inside Ethernet packets. As a new choice of the building blocks for SANs (Storage Area Networks), FCoE does not involve TCP/IP protocol processing that dominates the iSCSI processing costs, so it is considered more suitable for the data center than iSCSI. This paper evaluates the performance of software implementations of FCoE and iSCSI. We compare the two approaches on throughputs, average I/O response time and CPU utilizations at different disk I/O sizes. The measurement data shows that FCoE software implementation has a little higher throughput and less average I/O response time at small I/O sizes and a little lower throughput and more average I/O response time at larger I/O sizes than iSCSI software implementation. We also conduct the experiments to learn the effect of Jumbo Ethernet frames for FCoE and iSCSI. To better understand the overheads of FCoE processing, we do a profile analysis of execution hotspots, and assess the impact of CRC computation on FCoE performance. The results call for the need for optimized FCoE Target software and CRC offload in NIC hardware.
PUBLISHER'S NOTE 25 August 2010: This paper has been updated, replacing the version published on 23 October 2009. If you downloaded the original version of the paper and no longer have access, please contact CustomerService@SPIEDigitalLibrary.org for assistance.
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With the growing scale of storage system, the traditional storage strategies can not match the requirements of storage
system. The attribute controlled object storage has brought about new revolution. Moreover, storage system must handle
an increasing variety of data storage needs. QoSS (Quality of Storage Service) has therefore become an important issue.
Based on a review of the current development in the object storage and QoS, a QoSS management framework and some
optimization strategies are proposed. We implement QoSS efficiently involved with the optimizations in object-based
storage systems in accordance with the proposed framework. An attribute-managed storage system with guaranteed
QoSS based on extension of OSD and iSCSI protocols is developed. We mainly extend the T10 OSD standard on the
delay and bandwidth attributes. The test results show that the proposed strategy can achieve the optimization of the
storage systems.
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Traditional RAID gradually becomes unable to satisfy most applications. It is reflected in two main
respects, one is the security problem of data in RAID system, the other is that one RAID controller can not use several
devices of different protocol. Now, the performance of RAID controller gets faster and faster, therefore, it is the right
time to use software encryption module instead of hardware encryption to guarantee the data confidentiality.
Furthermore, with the development of storage device, different disk interface appears. How to use the disk of different
protocol in the same RAID controller is becoming a new research hotspot. As to the problems mentioned above, this
paper presents a new multi-protocol disk array architecture that provides encryption on RAID, referred to as Encryption
Multi-protocol RAID (EMRAID). EMRAID solution not only uses different interface to management the different kinds
of device, but also adopts SEAL algorithm which is an efficient pseudorandom function family encryption algorithm.
Analysis result indicates that EMRAID performs more efficiently than the single-protocol RAID, and the experiment
shows that the encryption algorithm has certain loss (not very large) on I/O performance.
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The main reason of causing the cost in p2p system is the maintenance cost that nodes build their routing information. In a
large-scale system or a dynamic environment, p2p system generates considerable maintenance workload, which not only
increase the bandwidth consumption but also affect the routing efficiency. So we present here a new Hierarchy_based
maintenance method to minimize the maintenance cost which combines the hierarchical DHT algorithm with a peer
proximity mechanism. The analysis results show our design can significantly decrease maintenance cost and improve
scalability of the P2P system.
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The giant magnetoimpedance (GMI) effect implies a strong dependence of the impedance of a
conductor on the external magnetic field and has been observed in a wide range of soft magnetic
materials. The impedance values of magnetic thin films and magnetic/conductor/magnetic sandwiched
structures with different thickness are simulated using the finite element method (FEM). The giant
magneto-impedance (GMI) is calculated from the difference of the impedance values with high and
low permeability of the magnetic material. The application of extra magnetic field can be simulated by
change the value of permeability. It is shown that the GMI ratio of films is significantly influenced by
the geometry. And the conductor layer can obviously increase the sensitivity of GMI effect. The skin
effect combined with the lack of shielding of the central conductor at the edge produce the high GMI
effect of sandwiched structure thin films.
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