• Journal of Information Technology Applications and Management
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• v.12 no.1
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• pp.125-140
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• 2005

Nowadays, we have many embedded systems which store and process multimedia data. For multimedia systems using hard disks as storage media such as DVR, existing file systems are not the right choice to store multimedia data in terms of cost. performance and reliability. In this study we designed a reliable file system with very high performance for embedded multimedia applications. The proposed file system runs with quite simple disk layout to reduce time to initialize and to recover after power failures, uses a large data block to speed up the sequential accesses, incorporates a time-based indexing scheme to improve the time-based random accesses and boosts reliability by backing up the important meta data on a small NVRAM. We implemented the file system on a Linux-based DVR and verified the performance by comparing with existing file systems.

• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.2
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• pp.90-103
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• 2006

There are many file systems in various operating systems. Those are usually designed for server environments, where the common cases are usually 'multiple active users', 'great many small files' And they assume a big main memory to be used as buffer cache. So the existing file systems are not suitable for resource hungry embedded systems that process multimedia data streams. In this study, we designed and implemented a new file system which efficiently stores and retrieves multimedia data steams. The proposed file system has a very simple disk layout, which guarantees a quick disk initialization and file system recovery. And we introduced a new indexing-scheme, called the time-based indexing scheme, with the file system. With the indexing scheme, the file system maintains the relation between time and the location for all the multimedia streams. The scheme is useful in searching and playing the compressed multimedia streams by locating exact frame position with given time, resulting in reduction of CPU processing and power consumption. The proposed file system and its APIs utilizing the time-based indexing schemes were implemented firstly on a Linux environment, though it is operating system independent. In the performance evaluation on a real DVR system, which measured the execution time of multi-threaded reading and writing, we found the proposed file system is maximum 38.7% faster than EXT2 file system.

• The KIPS Transactions:PartA
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• v.17A no.2
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• pp.63-72
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• 2010

Recently, the need for multimedia devices, such as digital TV, and camcorder has increased. These devices provide many services on multimedia files such as playing, recording, and editing. Throughout these services, in case of storing edited large-scaled multimedia files, existing file system have several capability problems that are taking too much time and requiring disk I/O. In this paper, we propose the use of Linux Ext2 file system based 'Block-Link file (BL-file) system' in order to solve these problems. For the BL-file system, when editing and storing large-scaled files, there is no data input or output but only modification of the metadata. Additionally, by sharing data blocks between multimedia files, we can save disk spaces. Moreover, because the managing of data block sharing information is more convenient than the existing FWAE technique, we can lessen system overhead. The BL-file system is based on Ext2 file system and implemented in a Linux environment, and the usefulness of the proposed technique is validated by applying the Linux multimedia file-editing tool 'Avidemux'.

• The KIPS Transactions:PartA
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• v.16A no.2
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• pp.89-100
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• 2009

With the advance in digital technologies and the increasing prevalence of high quality multimedia contents, there is a growing user demand for multimedia devices, such as mobile phones, digital TV, PMP, digital camcoders, digital cameras. Such devices provide various services associated with multimedia file manipulation, including multimedia contents playback, multimedia file editing, etc. Conventional file systems exhibit a performance-related drawback that requires considerable amount of time and disk I/Os in order to store large-sized edited multimedia files. This paper proposes a fast, efficient writing technique for large-sized edited multimedia files by using data block sharing with adjustment of inode block pointers. Our experiments show that the proposed scheme not only improves write performance of the Ext3 file system on average by 16 times with various types of edited multimedia files, but also reduces consumed disk space dramatically through the data block sharing.

• Journal of Broadcast Engineering
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• v.8 no.4
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• pp.392-398
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• 2003

In this paper, we propose the structure of multimedia file format based on MPEG-21 standard and the method to address a media resource within the file. The proposed multimedia file format supports the backward compatibility with MPEG-4 and the efficient addressing a media resource from a Digital Item that is XML-based MPEG-21 content. Also, the proposed multimedia file format can provide the functionality to package various types of media contents structurally and efficiently in digital broadcasting, Internet, and wireless environment. In addition, it can be a base model for multimedia file format that can be used for many different purposes such as integration and usage of metadata and multimedia contents.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.100-102
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• 2001

Intensive I/O bandwidth demand of the multimedia streaming service puts significant burden on file system. Different from the legacy text based or image data, the semantics of the data in multimedia format can be significantly affected if the data block is not delivered by the predefined deadline. The legacy file system used in Unix or Unix like environment is designed to efficiently handle the files who sizes range from few hundreds of byte to several tens of gigabytes. This fundamental design philosophy results in the file system based on multi level skewed tree structure. Multi level i-node structure has significant drawback when the application performs sequential read operation. In this article, we present the result of the performance study of the file system which is specifically designed for handling multimedia streams. We implemented the file system on Linux Operating System environment and examines the performance behavior of the file system under streaming I/O workload. The result of the study shows that the proposed file system performs much more efficiently than the ext2 file system of Linux does.

• Journal of Information Technology Applications and Management
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• v.10 no.4
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• pp.169-183
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• 2003

In multimedia systems, very large files are stored and played. Because those files are read-centric and have low reusability, legacy file systems that are optimized for the use of many small files, do not show good performance in the multimedia systems. We implemented a new file system to deal with those characteristics. The new file system shows the superior performances in read, write and mixed operation to the Linux's EXT2 or EXT3 file systems. The new file system was implemented on the Linux operating system, and it also can be easily ported to other operating systems.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1705-1708
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• 2005

Recently, flash memory is becoming popular as storage system to store and retrieve multimedia files. However, there are few researches about multimedia file system for flash memory based storage devices. We have been designing and developing a novel multimedia file systems for flash memory. In this paper, we describe the semantics of real-time retrieval of multimedia data and present scheduling scheme to guarantee the real-time requirements in our multimedia file system.

• Journal of Korea Multimedia Society
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• v.4 no.6
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• pp.489-499
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• 2001

This paper presents the SIC(Size-Interval-Count) prefetching system that can record the file access patterns of applications within a relatively small space of memory based on the repetitiveness of the file access patterns. The SICPS(SIC Prefetching System) is based on knowledge-based prefetching methods which includes high correctness in predicting future accesses of applications. The proposed system then uses the recorded file access patterns, referred to as "SIC access pattern information", to correctly predict the future accesses of the applications. The proposed prefetching system improved the response time by about 40% compared to the general file system and showed remarkable memory efficiency compared to the previously knowledge-based prefetching methods.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.527-535
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• 2004

Handling mixed workload in digital set-top box or streaming server becomes an important issue as integrated file system gets momentum as the choice for the next generation file system. The next generation file system is required to handle real-time audio/video playback while being able to handle text requests such as web page, image file, etc. Legacy file system provides only best effort I/O service and thus cannot properly support the QoS of soft real-time I/O. In this paper, we would like to present our experience in developing the file system which fan guarantee the QoS of multimedia stream. We classify all application I/O requests into two category: periodic I/O and sporadic I/O. The QoS requirement of multimedia stream could be guaranteed by giving a higher priority to periodic requests than sporadic requests. The proto-type file system(Qosfs) is developed on Linux Operating System.