• Title/Summary/Keyword: hybrid hard disk

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Design and Implementation of Hybrid Hard Disk Simulator based on Linux Environment (Linux 기반의 하이브리드 하드 디스크 시뮬레이터 설계 및 구현)

  • Lee, Geun-Hyung;Kim, Deok-Hwan
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.649-650
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    • 2008
  • In order to resolve mechanical limit in HDD, recently, the hybrid hard disk combining HDD and a flash memory was launched. In this paper, we propose a simulator for hybrid hard disk which considers redirection, flushing and spin-down function to complement the difference between HDD and hybrid hard disk. The simulator was implemented in linux kernel 2.6.20 by modifying system calls related with file system. The experiment shows that the power consumption of hybrid hard disk is 47% smaller than that of hard disk in laptop PC.

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Embedded Node Cache Management for Hybrid Storage Systems (하이브리드 저장 시스템을 위한 내장형 노드 캐시 관리)

  • Byun, Si-Woo;Hur, Moon-Haeng;Roh, Chang-Bae
    • Proceedings of the KIEE Conference
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    • 2007.04a
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    • pp.157-159
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    • 2007
  • The conventional hard disk has been the dominant database storage system for over 25 years. Recently, hybrid systems which incorporate the advantages of flash memory into the conventional hard disks are considered to be the next dominant storage systems to support databases for desktops and server computers. Their features are satisfying the requirements like enhanced data I/O, energy consumption and reduced boot time, and they are sufficient to hybrid storage systems as major database storages. However, we need to improve traditional index node management schemes based on B-Tree due to the relatively slow characteristics of hard disk operations, as compared to flash memory. In order to achieve this goal, we propose a new index node management scheme called FNC-Tree. FNC-Tree-based index node management enhanced search and update performance by caching data objects in unused free area of flash leaf nodes to reduce slow hard disk I/Os in index access processes.

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Effecient Prefetching Scheme for Hybrid Hard Disk (하이브리드 하드디스크를 위한 효율적인 선반입 기법)

  • Kim, Jeong-Won
    • The Journal of the Korea institute of electronic communication sciences
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    • v.6 no.5
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    • pp.665-671
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    • 2011
  • The Competitiveness of Hybrid hard disk drive(H-HDD) for solid state disk(SSD) comes from both lower power consumption and higher reading speed. This paper suggests a prefetching scheme that can improve the performance of Non-Volatile cache(NVCache) memory installed on the H-HDD through prefetching disk blocks as well as files to the NVCache. The proposed scheme makes the highly used data such as booting files copy to the NVCache as an unit of file and the frequently accessed blocks copy to the NVCache. This prefetching is done on the idle time of disk queue and the priorities of prefetched target blocks are based on both time and spatial locality of blocks. Experiments results show that the suggested method can improve response time of H-HDD and also lower the power consumption.

I/O Scheme of Hybrid Hard Disk Drive for Low Power Consumption and Effective Response Time (저전력과 응답시간 향상을 위한 하이브리드 하드디스크의 입출력 기법)

  • Kim, Jeong-Won
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.10
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    • pp.23-31
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    • 2011
  • Recently, Solid state disk is mainly used because this device has lower power consumption as well as higher response time. But it features higher price and lower performance at delete and write operations compared with HDD. To compensate this defect, Hybrid hard disk with internal non-volatile flash memory was issued. This NVCache is used as a kind of cache for disk blocks. In this paper, an I/O scheme for H-HDD is proposed for improving low power consumption as well as response time. Our method is to use this NVCache as read cache mainly and write cache when write requests are concentrated. In read cache operation, disk blocks with higher priority determined on basis of time as well as spatial localities are prefetched, which can improve response time. The write operation is conducted only at write peak time as disk spindle up costs higher battery power as well as response time. Experiments results show that the suggested method can improve response time of H-HDD and lower the power consumption.

A Block Replacement Scheme using Analytic Hierarchy Process in Hybrid HDD (하이브리드 하드디스크에서 AHP를 적용한 블록 교체 기법)

  • Kim, Jeong-Won
    • Journal of Korea Society of Industrial Information Systems
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    • v.20 no.5
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    • pp.45-52
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    • 2015
  • The read performance of hybrid hard disk is better than the legacy hard disk and power consumption is also considerably low. As blocks with enough localities may be located in the non-volatile cache whose size is generally limited, an effective block replacement scheme is required. As this replacement is inevitably affected by various parameters, we define this issue as a kind of multiple criteria decision model. To solve this problem, this paper suggests a new block replacement algorithm based on the analytic hierarchy process. Through simulation for our model, we confirmed that the proposed model could be used as a replacement algorithm of the hybrid hard disk as it may improve boot time as well as response time of general applications.

Flash Node Caching Scheme for Hybrid Hard Disk Systems (하이브리드 하드디스크 시스템을 위한 플래시 노드 캐싱 기법)

  • Byun, Si-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1696-1704
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    • 2008
  • The conventional hard disk has been the dominant database storage system for over 25 years. Recently, hybrid systems which incorporate the advantages of flash memory into the conventional hard disks are considered to be the next dominant storage systems. Their features are satisfying the requirements like enhanced data I/O, energy consumption and reduced boot time, and they are sufficient to hybrid storage systems as major database storages. However, we need to improve traditional index management schemes based on B-Tree due to the relatively slow characteristics of hard disk operations, as compared to flashmemory. In order to achieve this goal, we propose a new index management scheme called FNC-Tree. FNC-Tree-based index management enhanced search and update performance by caching data objects in unused free area of flash leaf nodes to reduce slow hard disk I/Os in index access processes. Based on the results of the performance evaluation, we conclude that our scheme outperforms the traditional index management schemes.

Improving Flash Translation Layer for Hybrid Flash-Disk Storage through Sequential Pattern Mining based 2-Level Prefetching Technique (하이브리드 플래시-디스크 저장장치용 Flash Translation Layer의 성능 개선을 위한 순차패턴 마이닝 기반 2단계 프리패칭 기법)

  • Chang, Jae-Young;Yoon, Un-Keum;Kim, Han-Joon
    • The Journal of Society for e-Business Studies
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    • v.15 no.4
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    • pp.101-121
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    • 2010
  • This paper presents an intelligent prefetching technique that significantly improves performance of hybrid fash-disk storage, a combination of flash memory and hard disk. Since flash memory embedded in a hybrid device is much faster than hard disk in terms of I/O operations, it can be utilized as a 'cache' space to improve system performance. The basic strategy for prefetching is to utilize sequential pattern mining, with which we can extract the access patterns of objects from historical access sequences. We use two techniques for enhancing the performance of hybrid storage with prefetching. One of them is to modify a FAST algorithm for mapping the flash memory. The other is to extend the unit of prefetching to a block level as well as a file level for effectively utilizing flash memory space. For evaluating the proposed technique, we perform the experiments using the synthetic data and real UCC data, and prove the usability of our technique.

An Efficient Data Block Replacement and Rearrangement Technique for Hybrid Hard Disk Drive (하이브리드 하드디스크를 위한 효율적인 데이터 블록 교체 및 재배치 기법)

  • Park, Kwang-Hee;Lee, Geun-Hyung;Kim, Deok-Hwan
    • Journal of KIISE:Computing Practices and Letters
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    • v.16 no.1
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    • pp.1-10
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    • 2010
  • Recently heterogeneous storage system such as hybrid hard disk drive (H-HDD) combining flash memory and magnetic disk is launched, according as the read performance of NAND flash memory is enhanced as similar to that of hard disk drive (HDD) and the power consumption of NAND flash memory is reduced less than that of HDD. However, the read and write operations of NAND flash memory are slower than those of rotational disk. Besides, serious overheads are incurred on CPU and main memory in the case that intensive write requests to flash memory are repeatedly occurred. In this paper, we propose the Least Frequently Used-Hot scheme that replaces the data blocks whose reference frequency of read operation is low and update frequency of write operation is high, and the data flushing scheme that rearranges the data blocks into the multi-zone of the rotation disk. Experimental results show that the execution time of the proposed method is 38% faster than those of conventional LRU and LFU block replacement schemes in I/O performance aspect and the proposed method increases the life span of Non-Volatile Cache 40% higher than those of conventional LRU, LFU, FIFO block replacement schemes.

HAMM(Hybrid Address Mapping Method) for Increasing Logical Address Mapping Performance on Flash Translation Layer of SSD (SSD 플래시 변환 계층 상에서 논리 주소 매핑의 성능 향상을 위한 HAMM(Hybrid Address Mapping Method))

  • Lee, Ji-Won;Roh, Hong-Chan;Park, Sang-Hyun
    • The KIPS Transactions:PartD
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    • v.17D no.6
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    • pp.383-394
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    • 2010
  • Flash memory based SSDs are currently being considered as a promising candidate for replacing hard disks due to several superior features such as shorter access time, lower power consumption and better shock resistance. However, SSDs have different characteristics from hard disk such as difference of unit and time for read, write and erase operation and impossibility for over-writing. Because of these reasons, SSDs have disadvantages on hard disk based systems, so FTL(Flash Translation Layer) is designed to increase SSDs' efficiency. In this paper, we propose an advanced logical address mapping method for increasing SSDs' performance, which is named HAMM(Hybrid Address Mapping Method). HAMM addresses drawbacks of previous block-mapping method and super-block-mapping method and takes advantages of them. We experimented our method on our own SSDs simulator. In the experiments, we confirmed that HAMM uses storage area more efficiently than super-block-mapping method, given the same buffer size. In addition, HAMM used smaller memory than block-mapping method to construct mapping table, demonstrating almost same performance.

Design and Implementation of Hybrid Hard Disk I/O System based on n-Block Prefetching for Low Power Consumption and High I/O Performance (저전력과 입출력 성능이 향상된 n-블록 선반입 기반의 하이브리드 하드디스크 입출력 시스템 설계 및 구현)

  • Yang, Jun-Sik;Go, Young-Wook;Lee, Chan-Gun;Kim, Deok-Hwan
    • Journal of KIISE:Computer Systems and Theory
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    • v.36 no.6
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    • pp.451-462
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    • 2009
  • Recently, there are many active studies to enhance low I/O performance of hard disk device. The studies on the hardware make good progress whereas those of the system software to enhance I/O performance may not support the hardware performance due to its poor progress. In this paper, we propose a new method of prefetching n-blocks into the flash memory. The proposed method consists of three steps: (1)analyzing the pattern of read requests in block units; (2)determining the number of blocks prefetched to flash memory; (3)replacing blocks according to block replacement policy. The proposed method can reduce the latency time of hard disk and optimize the power consumption of the computer system. Experimental results show that the proposed dynamic n-block method provides better average response time than that of the existing AMP(Adaptive multi stream prefetching) method by 9.05% and reduces the average power consumption than that of the existing AMP method by 11.11%.