The access time of Disk/RAID has not been improved as fast as the memory performance whose rate of improvement has been 25% per year and hence the disk access penalty is considerably increasing with each enhancement in the memory architecture. To solve the problem, a new kind of storage hierarchy, Volume Holographic Universal Storage Cache (short for VHUSC) is proposed. VHUSC acts as a layer between main memory and disk or disk array. VHUSC can lower the disk access latency, provide much higher I/O bandwidth and throughput, it thus greatly improve the I/O performance of computer system. In this paper, an application independent model based on queuing theory is proposed for the VHUSC performance evaluation. Based on this model, VHUSC and traditional disk/RAID performance is analyzed and compared. Result shows that in most cases VHUSC can improve the disk read/write performance by 1 order of magnitude, especially when the hit rate is larger than 99%, the performance can reach 2 orders of magnitude.
The Volume Holographic Data Storage (VHDS) is an optical technology that allows one million bits of data to be written and read out in single flashes of light. To accommodate the characteristics of VHDS, this paper presents the following strategies in designing the file system based on VHDS: (1) Construct the virtual storage layer on the Holographic Storage media, which turns the storage-on-pages into the storage-on-blocks. (2) Use the two-layer structure of the directory table and the index node, and the data stored in the immediate area of the index node. This method can access the index node and the content (partial or all) of the file with an accessing operation. (3) Adopt the allocating method of the page priority in storing data--allocate the whole page to a file while the length of the file exceeds the page. In the meantime, a page is partitioned into many zones to enhance the storing utilities of VHDS. (4) To meet the three-dimension storage's need, the two-dimension Logical Block Address (LBA) is to be used, and makes the more continuity between data blocks--allocate the continuous data blocks in vertical and horizontal direction while storing data. The simulation test shows that the file system can be compatible with the existing file system, and has better stability.
This paper presents a novel storage architecture called Volume Holographic Universal Storage Cache (for short VHUSC) for the purpose of optimizing disk I/O performance. The main idea of VHUSC is to make use of the Volume Holographic Memory, referred to as VHUSC, as a new layer between main memory and disk. VHUSC can lower the disk access latency, provide much higher I/O bandwidth and throughput. An application independent model based on queuing theory is proposed for performance comparison between VHUSC and traditional disk. The results show performance improvements of up to one order of magnitude.
A iSCSI-based CD mirroring server (iCDMS) has been developed and tested. Firstly, the iCDMS can automate to concurrently mirror multi- CD with multi- CD drivers, and the CD includes VCD, DVD, and so on. Secondly, the iCDMS can provide both of the file I/O and the block I/O services by an iSCSI module, which converges the NAS and SAN advantages, as high performance and data sharing across platforms. Thirdly, the iCDMS greatly improves the I/O speed by Zero Copy mechanism. Fourthly, the iCDMS implements automatically - allocating I/O bandwidth for different users and applications by enriching the metadata operating semantic of the CD server, and allocate a wider bandwidth for applications that has higher priority, changing the old average allocating bandwidth pattern. Finally, the iCDMS improves paralleled file I/O performance with a parallel FTP server module. In the experiments, the iCDMS has ultra-high-throughput for both of the file I/O requests and the block I/O requests
A calorific equilibrium equation is used to derive the relativities of optimum recording power and pulse waveform parameters in various disc scanning velocities. Based on the model, a new recording parameters calibrating flow is given as a referenced process. A number of optical recording examples have been examined in detail, and the results have been compared with those calculated data by use of a general summation approach.