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.

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.

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.

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.

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.

Tellurium oxide (TeO_x) 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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 (AgO_x) 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.

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.

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.

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.

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.

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.

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.

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.

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.

Light rare earth-heavy rare earth-transition metal films (LRE-HRE-TM)have large saturation magnetization (M_s) 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 (H_c)and the temperature stability of magnetic properties decrease distinctly. These results can be explained by the ferri-magnetic structure of the RE-TM alloy.

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.

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.

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.

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.

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.

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.

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.

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.