• KIPS Transactions on Computer and Communication Systems
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• v.4 no.9
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• pp.327-336
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• 2015

Mobile game servers usually execute frequent dynamic memory allocation for generating the buffers that deal with clients requests. It causes to deteriorate the performance of game servers since it increases system workload and memory fragmentation. In this paper, we propose fixed-sized memory pool management method. Memory pool for the proposed method has a sequential memory structure based on circular linked list data structure. It solves memory fragmentation problem and saves time for searching the memory blocks which are required for memory allocation and deallocation. We showed the efficiency of the proposed method by evaluating the performance of dynamic memory allocation, through the proposed method and the memory pool management method based on boost open source library.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.19-26
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• 2009

Recently, the Main Memory DBMS is gradually being expanded by the appearance of a large capacity of a Main Memory System, the increase in business area where it requires a real time process, and the rise of the users' required level. The Main Memory DBMS, which is able to go through a large capacity data process of the disk-based DBMS and guarantees a high efficiency, has domestically developed and has been put to a practical use. This paper presents an examination of the applied technologies and the limits of Altibase system, which is Main Memory DBMS. Moreover, it evaluated and performed a comparative analysis on the performance level of the Main Memory DBMS and the disk-based DBMS based on the same application. After five trials of the experiment based on the operating application, it was confirmed that the performance level of the Main Memory DBMS is enhanced and is higher by 4.13 to 7.89 times than the disk-based DBMS.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.185-188
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• 1991

In this paper we have designed and implemented a method of using extended memory and hard disk space as a data buffer for application programs to allow handling of large data files in DOS environment. We use a part of the conventional DOS memory as a buffer cache which allows the application program to use extended memory and hard disks transparently. Using buffer cache also allows some speed improvement for the application program. We have also implemented a number of functions to allow easier handling of pointer operations used by application programs.

• Journal of the Korea Society of Computer and Information
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• v.25 no.2
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• pp.21-29
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• 2020

The use of NAND flash memory is continuously increased with the demand of mobile data in the IT industry environment. However, the erase operations in flash memory require longer latency and higher power consumption, resulting in the limited lifetime for each cell. Therefore, frequent write/erase operations reduce the performance and the lifetime of the flash memory. In order to solve this problem, management techniques for improving the performance of flash based storage by reducing write and erase operations of flash memory with using disk buffers have been studied. In this paper, we propose a CPWL to minimized the number of write operations. It is a disk buffer management that separates read and write pages according to the characteristics of the buffer memory access patterns. This technique increases the lifespan of the flash memory and decreases an energy consumption by reducing the number of writes by arranging pages according to the characteristics of buffer memory access mode of requested pages.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.4
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• pp.177-185
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• 2005

NAND-type flash memory is becoming increasingly popular as a large data storage for mobile computing devices. Since flash memory is an order of magnitude more expensive than magnetic disks, data compression can be effectively used in managing flash memory based storage systems. However, compressed data management in NAND-type flash memory is challenging because it supports only page-based I/Os. For example, when the size of compressed data is smaller than the page size. internal fragmentation occurs and this degrades the effectiveness of compression seriously. In this paper, we present an efficient flash compression layer (FCL) for NAND-type flash memory which stores several small compressed pages into one physical page by using a write buffer Based on prototype implementation and simulation studies, we show that the proposed scheme offers the storage of flash memory more than $140\%$ of its original size and expands the write bandwidth significantly.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.51-56
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• 2009

Flash memory has rapidly deployed as data storage. However, the flash memory has a major disadvantage that recorded data cannot be dynamically overwritten. In order to solve this "erase-before-write" problem, the log block buffer scheme used Flash memory file system. however, the current managements of the log buffer, in case random write pattern, BAST technique have problem of frequent merge operation, but FAST technique don't consider merge operation by frequently updated data. Previous methods not consider merge operation cost and frequently updated data. In this paper, we propose a new log buffer management scheme, called JBB. Our proposed method evaluates the worth of the merge of log blocks, so we conducts the merge operation between infrequently updated data and its data blocks, and postpone the merge operation between frequently updated data and its data blocks. Through the method, we prevent the unnecessary merge operations, reduce the number of the erase operation, and improve the utilization of the flash memory storage. We show the superiority of our proposed method through the performance evaluation with BAST and FAST.

• Journal of Information Technology Applications and Management
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• v.12 no.4
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• pp.59-70
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• 2005

Flash memories are one of best media to support portable computer's storages in mobile computing environment. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major database storage components of portable computers. However, we need to improve traditional transaction management scheme due to the relatively slow characteristics of flash operation as compared to RAM memory. in order to achieve this goal, we devise a new scheme called Flash Two Phase Locking (F2PL) scheme for efficient transaction processing. F2Pl improves transaction performance by allowing multi version reads and efficiently handling slow flash write/erase operation in lock management process. We also propose a simulation model to show the performance of F2PL. Based on the results of the performance evaluation, we conclude that F2PL scheme outperforms the traditional scheme.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.33-41
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• 2014

This paper presents an effective memory access method for a high-speed data transfer on mobile systems using a direct memory access controller that considers the characteristics of a multi-port memory controller. The direct memory access controller has an integrated channel management function to control multiple direct memory access channels. The channels are physically separated and operate independently from each other. Experimental results show that the proposed direct memory access method improves the transfer performance by up to 72% and 69% on read and write transfer cycles, respectively. The total number of transfer cycles of the proposed method is 63% less than in a commercial method under 4-channel access.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.434-441
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• 2001

The concept of network memory was introduced for the efficient exploitation of main memory in a cluster. Network memory can be used to speed up applications that frequently access large amount of disk data. In this paper, we present a memory a management algorithm that does not require prior knowledge of access patterns and that is practical to implement under the web server cluster, In addition, our scheme has a good user response time for various access distributions of web documents. Through a detailed simulation, we evaluate the performance of our memory managment algorithms.

• Journal of the Korea Society of Computer and Information
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• v.25 no.6
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• pp.99-107
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• 2020

In this paper, we analyze the characteristics of mobile cache, which is used to improve the data access speed when executing applications on mobile devices, and verify the importance of mobile cache through a cache data access experiment. The mobile device market has grown at a fast pace over the past decade; however, battery limitations and size, price considerations restrict the usage of fast hardware. Thus, their performance are supplemented by using a memory buffer structure such as the cache memory. The analysis mainly focuses on cache size, hierarchical structure of cache, cache replacement policy, and the effect these features has on mobile performance. For the experimental data, we applied a data set from a microprocessor system study, originally used to test the cache performance. In the experimental results, the average data access speed on a mobile device showed a performance improvement of up to 10 times with the presence of cache memory than without. Accordingly, the cache memory was helpful for the performance improvement of a mobile device when the specifications were identical.