• KIPS Transactions on Computer and Communication Systems
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• v.2 no.10
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• pp.413-420
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• 2013

Redundant arrays of independent disks (RAID) without a power-fail-safe component in small and mid-sized business suffers from intolerably long resynchronization time after a unclean power-failure. Data blocks and a parity block in a stripe must be updated in a consistent manner, however a data block may be updated but the corresponding parity block may not be updated when a power goes off. Such a partially modified stripe must be updated with a correct parity block. However, it is difficult to find which stripe is partially updated (inconsistent). The widely-used traditional parity resynchronization manner is a intolerably long process that scans the entire volume to find and fix inconsistent stripes. This paper presents a fast resynchronization scheme with a negligible overhead for small and mid-sized RAIDs. The proposed scheme is integrated into a software RAID driver in a Linux system. According to the performance evaluation, the proposed scheme shortens the resynchronization process from 200 minutes to 5 seconds with 2% overhead for normal I/Os.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.149-152
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• 2003

최근 VOD 서버 모델로 제안되는 클러스터형 VOD 서버는 확장성과 가용성을 높일 수 있다는 장점이 있지만 서버에 노드수가 증가하면서 서버에 장애가 발생할 가능성이 높아지는 문제점을 가지고 있다. 본 논문에서는 클러스터형 VOD 서버에서 노드 장애 발생시 이를 복구하기 위한 방안으로서 RAID-3, 4의 특성을 취합하고, 이에 파이프라인 개념을 더한 복구 시스템을 제시하고자 한다. 본 복구 시스템은 RAID-4 개념을 도입하여 디스크로의 접근을 큰 사이즈의 블록단위로 함으로써 디스크의 효율성을 증가시키며, 네트웍에는 RAID-3 개념을 적용하여 작은 사이즈의 블록으로 나누어 전송함으로써 네트웍을 효율적으로 사용하고 메모리 부하를 줄일 수 있도록 한다. 또한 파이프라인 개념을 도입하여 복구과정을 여러 노드에서 분담하여 동시에 처리함으로써 CPU, 네트웍, 메모리 등과 같은 자원에 대한 부하가 모든 노드로 분산되도록 한다.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.195-200
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• 2013

In visual surveillance system abandoned objects in public places are the deliberately left things, which should be automatically detected by intelligent systems in the environment where the number of cameras is increasing. This research deals with the design scheme of a smart security disk system which can detect these abandoned objects automatically and save the relevant image information with the wireless interface of high definition images. By implementing the proposed system in this research it is confirmed that the transmission performance shows 60 frames per second without compression of high definition images and the capability of the disk system shows the relevant images can be saved in a RAID configuration. Also, the proposed visual surveillance software shows a good detection rate of 80% in PAT performance.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.353-356
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• 2002

RAID 레벨 중에서 스트라이핑을 하는 시스템에서는 운영중에 디스크를 추가하려면, 기존의 디스크에 저장되어 있는 데이터들은 새로 추가된 디스크를 고려하여 스트라이핑 하기 위해 재구성하는 과정이 필요하다. 이러한 동적디스크 수의 변화에 유연하게 적응할 수 있도록 매핑 테이블을 사용하는 방법들이 제안되고 있으나 관리해야 할 데이터의 양이 디스크 용량에 비례하여 증가하고 메인 메모리에서 모두 관리할 수 없기 때문에 성능이 떨어지는 문제가 발생한다. 이 논문에서는 스트라이핑을 하는 RAID 시스템에서 적은 양의 메타데이터(SZIT)를 관리함으로써 동적 디스크 수를 지원하는 계산에 의한 매핑 방법을 제안한다.

• The KIPS Transactions:PartA
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• v.13A no.6 s.103
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• pp.517-524
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• 2006

In cluster computers, it is essential to Implement the single I/O space(SIOS) supporting integrated I/O substructure to efficiently process I/O intensive applications. SIOS service provides with global I/O address space to directly access peripherals and hard disks in its own or remote nodes from any node in the cluster computer In this thesis, we propose the implementation method of SIOS in Linux clusters by using only freewares. This method is implemented at device driver level that uses Enhanced Network Block Device(ENBD) and file system level that uses S/W RAID and NFS. The major strengths of this method are easiness of implementation and almost no cost due to using freewares. In addition, since freewares used are open sources, it is possible to apply this method to other platforms with only slight modification. Moreover, experiments show that I/O throughputs are up to 5.5 times higher in write operations and approximately 2.3 times higher in read operations than those of CDD method that uses the device driver developed at kernel level.

• Management Science and Financial Engineering
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• v.19 no.2
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• pp.31-36
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• 2013

We propose a war-game model that is appropriate for a raid-type warfare in which, a priori, the maneuver of the attacker is relatively certain. The model is based on a multi-weapon extention of the Lanchester's law. Instead of a continuous time dynamic game with the differential equations from the Lanchester's law, however, we adopt a multi-period model relying on a time-discretization of the Lanchester's law. Despite the obvious limitation that two players make a move only on the discrete time epochs, the pragmatic model has a manifold justification. The existence of an equilibrium is readily established by its equivalence to a finite zero-sum game, the existence of whose equilibrium is, in turn, well-known to be no other than the LP-duality. It implies then that the war-game model dictates optimal strategies for both players under the assumption that any strategy choice of each player will be responded by a best strategy of her opponent. The model, therefore, provides a sound ground for finding an efficient reinforcement of a defense system that guarantees peaceful equilibria.

• The Transactions of the Korea Information Processing Society
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• v.4 no.11
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• pp.2662-2670
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• 1997

High speed network makes possible to transfer not only the test data but also multimedia data such as audio, image, and moving pictures and etc. In a multimedia applications, as a multimedia storage system, it is necessary to use a disk array to store and retrieve data by real time. It is important feature to various disk array parameters as a storage system on a real VOD system, such as configuration method of each disks and allocation method of multimedia data. In this paper, various parameters for the disk array are decided to be used for the video-on-demand system application by simulations in two ways. The real and simulation measurement are compared and analyzed on the performance. Simulation results shows that RAID level 5 and 256KB as striping unit and 185KB as data requests size per seconds are suitable parameter for the disk array architecture which provides MPEG-1 files with a rate of 1.5Mbps in two measurements of real and simulation.

• The KIPS Transactions:PartB
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• v.9B no.2
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• pp.191-198
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• 2002

Recently, Usage of multimedia server is rapidly increased with expansion of internet that real-time displaying service for multimedia data, MPEG and etc. For these multimedia real-time applications, it is necessary to use a disk array as a storage system. For providing requested service to much more clients at the same time in a multimedia data storage server, considerable varied strategies in a several parts. But especially it is important feature to various parameters for disk array such as relation of striping block size as a system environment and characteristics of video data. In this paper, we implemented real environment of multimedia server which provides MPEG-1 files and evaluated the suitable storage system architectures by applying synthetically generated workloads in the various parameters for disk array.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.287-292
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• 2001

Multimedia service systems should have efficient capacity to serve the growing clients and new data. In the general streaming services, users can endure the small amount of time delay at the beginning of service. But they want to have good quality of service. A streaming server tries to transfer video files to clients from a repository of files in real time. The server must guarantee concurrent and uninterrupted delivery of each video stream requested from clients. To achieve its purpose, many stream servers adopt multi-processors, sufficient memory, and RAID or SAN in their systems. In this paper, we propose a Linux-based parallel media streaming server. It is superior to the other systems in the storing structure, fault-tolerance, and service capacity. Since this system supports the web interlace, users can operate easily through the www. This system uses unique striping policy to distribute multimedia files into the parallel storage nodes. If a service request occurs, each storage node transmits striped files concurrently to the client. Its performance is better than the single media streaming service because of the parallel architecture.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.179.3-179
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• 2001

This paper describes the dual system technology of PC based control system at steel plant. Because PC is developed to be used in wide area such as Office Automation, Personal, It is cheaper and more portable than the present process control system, but is less stable and less reliable. In this research, We gathered the fault example of a general process control system and steel process control system, analyzed the cause of fault and decided the target fault that took over in our proposed system. The proposed PC based system is the dual system that has a shared RAID system connected by SCSI bus between two systems. In order to assist system reliability, we proposed watchdog manager to monitor ...