• International journal of advanced smart convergence
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• v.12 no.1
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• pp.76-81
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• 2023

Journaling file systems are widely used to keep file systems in a consistent state against crash situations. As traditional journaling file systems are designed for block I/O devices like hard disks, they are not efficient for emerging byte-addressable NVM (non-volatile memory) media. In this article, we present a new in-memory journaling file system for NVM that is different from traditional journaling file systems in two respects. First, our file system journals only modified portions of metadata instead of whole blocks based on the byte-addressable I/O feature of NVM. Second, our file system bypasses the heavy software I/O stack while journaling by making use of an in-memory file system interface. Measurement studies using the IOzone benchmark show that the proposed file system performs 64.7% better than Ext4 on average.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.405-410
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• 2012

Several attempts have been made to add journaling capability to a traditional file allocation table (FAT) file system. However, they encountered issues such as excessive system load or instability of the journaling data itself. If journaling data is saved as a file format, it can be corrupted by a user application. However, if journaling data is saved in a fixed area such as a reserved area, the storage can be physically corrupted because of excessive system load. To solve this problem, a new method that dynamically allocates journaling data is introduced. In this method, the journaling data is not saved as a file format. Using a reserved area and reserved FAT status entry of the FAT file system specification, the journaling data can be dynamically allocated and cannot be accessed by user applications. The experimental results show that this method is more stable and scalable than other log-based FAT file systems. HFAT was tested with more than 12,000 power failures and was stable.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.45-51
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• 2019

Modern file systems have journaling mechanism to maintain their stored state consistently even under unexpected system crashes or disasters. However, the journaling makes I/O throughput lower. This performance degradation comes from the ordering mechanism between the data buffer and metadata buffer and two-staged buffer writing. Especially, if the data buffer and metadata buffer are journalled at the same time, then it incurs significant performance degradation due to the two-staged writing. That shows the trade-off relation-ship between I/O performance and system reliability. In this paper, we propose RFJ: a reliable and fast jour-naling mechanism to deal with this trade-off relationship. We propose an ordering enforced writeback journaling mode and selective journaling mechanism. The Ordering enforced writeback journaling mode achieves low I/O latency and the selective journaling mechanism achieves high reliability. The experimental result shows that the performance of RFJ is almost 5x faster than the journal mode of Ext3 file system but it still supports the same reliability with the journal mode.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.107-111
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• 2023

Journaling techniques are widely used to maintain a consistent file system state in the event of a system crash. As existing journaling techniques are designed for block storage such as HDDs, they are not efficient for byte-addressable persistent memory media. This paper proposes a metadata journaling technique for in-memory file systems that has the ability of avoiding inconsistent file system states in crash situations. The proposed journaling technique reduces a large amount of writing by making use of the byte-addressable feature of memory media and bypasses heavy software I/O stack. Experimental results with the IOzone benchmark show that the proposed journaling technique improves the performance of Ext4 by 49.2% on average.

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.157-163
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• 2021

A single write operation in a file system can modify multiple data, but these changes in the file system are not atomically written to disk. Thus, for the consistency of the file system, conventional journaling guarantees crash consistency instead of sacrificing the system performance. It is known that using non-volatile memory as a journal space can alleviate performance degradation due to low latency and byte-level accessibility of non-volatile memory. However, none of the journaling techniques considering non-volatile memory provide scalability. In this paper, journal space on non-volatile memory is divided into multiple regions for scalable journaling, thus dispersing concentrated operations in one region. Second, the journal area-specific operator structure is used to accelerate data write operations to storage devices. We apply the proposed technique to JFS to evaluate it on multi-core servers equipped with high-performance storage devices. The evaluation results show that the proposed technique performs better than the existing technique of the NVM-based journaling file system.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.3
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• pp.191-198
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• 2009

The FAT (File Allocation Table) compatible file system has been widely used in mobile devices and memory cards because of its data exchangeability among numerous platforms recognizing the FAT file system. By the way. modern embedded systems have tough demands for instant power failure recovery and superior performance for multimedia applications. The key issue is how to achieve the goals of superior write performance and instant booting capability while controlling compatibility issues. To achieve the goals while controlling compatibility issues. we devised a temporary meta-data journaling scheme for a FAT compatible file system. Benchmark results of the scheme implemented in a FAT compatible file system shows that it really improves write performance of the FAT file system by converting small random write for meta-data update to a large sequential write in journaling area. Also, it provides natural way to implement the instant booting capability. Nevertheless, the file system compatibility is temporarily compromised by the scheme because it stores updated meta-data in the temporary journaling area rather than to their original locations. However, the compatibility can be fully recovered at any time by journal-flushing that copies meta-data in journaling area to their original locations. Generally, the journal-flushing is done before un-mounting a memory card so that it can be used in other mobile devices which recognized FAT file system but not the temporary meta-data journaling scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.633-636
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• 2011

In this paper, ordered mode of EXT3 file system offers to use an optional compression algorithm technique. If the system terminates abnormally or an error occurs, data which is being modified will be possibly damaged or a recovery of the existing data can be impossible. To overcome these problems, a journaling file system is used. Journaling file system manages by using an additional space called Journal. EXT3 file system is the most widely used journaling file system. In this paper, When performing a file writing of an existing EXT3 file system, it offers to use an optional compact algorithm technique for an efficient use of a space of storage device.

• English Language & Literature Teaching
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• v.16 no.3
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• pp.291-315
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• 2010

The present study examined the role of dialogue journaling in Korean students' English writing development. Thirteen Korean middle school students participated in a five-week dialogue journal writing program. The participants' English writing skills before and after their dialogue journaling were compared in terms of holistic and analytical scores of their English essays. The study also examined the changes in the participants' language use, as manifested in their dialogue journals. The results indicated the positive influence of dialogue journal writing on the participants' English writing skills in the areas of content and lexical fluency. As for the linguistic evidence that related dialogue journaling to English writing development, the three patterns of change in language use emerged from the participants' dialogue journals: a) raised awareness on grammar conventions, b) raised awareness on discourse conventions, and c) increased depth and richness in idea development. There were also three unhelpful factors associated with little improvement of English writing: a) lack in basic writing skills, b) repetitive use of identical sentence patterns, and c) lack in grammatical and lexical awareness. Overall, the results suggested that dialogue journaling could facilitate Korean students' English writing development when it creates authentic communicative interactions between the teacher and students.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.39-46
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• 2013

If a file system is damaged because of the unusual system close, the system performs the consistency test using fsch and it takes long time. Especially, if it is a big file system, it will take a lot of time. The journaling file system that uses journaling technique, can reduce the restoring time because it uses meta data and it may increase the chance of restoration when restoring. The goal of this paper compared performance evaluation journaling file systems focused on the reading and writing using Iozone tool which is the kernel based benchmarking tool in linux operating system. In this paper, Ex4 which is the current basic Linux file system. is 1.28x faster than XFS file system in terms of file read performance and 1.22x faster than Ext3 file system in terms of file write performance.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.375-384
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• 2001

The shared disk file systems use a technique known as file system journaling to support recovery of metadata on the SAN(Storage Area Network). In the existing journaling technique, the metadata that is dirtied by one host must be updated to disk space before some hosts access it. The system performance is decreased because the disk access number is increased. In this paper, we describe a new recovery technique using a global buffer to decrease disk I/O. It transmits the dirtied metadata into the other hosts through Fibre Channel network on the SAN instead of disk I/O and supports recovery of a critical data by journaling a data as well as metadata.