• Proceedings of the KIEE Conference
• /
• 2003.11c
• /
• pp.709-712
• /
• 2003

In this research, we port the RT-Linux to MVME 5100 board which is driven by VxWorks or Vertex until now. And, we developed the data logging modules by using the RT-Linux. This module gathers two different scan timing data from plant and sends this data to the host controller with real time.

• International journal of advanced smart convergence
• /
• v.10 no.1
• /
• pp.142-150
• /
• 2021

Open-channel SSD is a new type of Solid-State Disk (SSD) that improves the garbage collection overhead and write amplification due to physical constraints of NAND flash memory by exposing the internal structure of the SSD to the host. However, the host-level Flash Translation Layer (FTL) provided for open-channel SSDs in the current Linux kernel consumes host memory excessively because it use page-level mapping table to translate logical address to physical address. Therefore, in this paper, we implemente a selective mapping table loading scheme that loads only a currently required part of the mapping table to the mapping table cache from SSD instead of entire mapping table. In addition, to increase the hit ratio of the mapping table cache, filesystem information and mapping table access history are utilized for cache replacement policy. The proposed scheme is implemented in the host-level FTL of the Linux kernel and evaluated using open-channel SSD emulator. According to the evaluation results, we can achieve 80% of I/O performance using the only 32% of memory usage compared to the previous host-level FTL.

• Journal of Korea Multimedia Society
• /
• v.2 no.3
• /
• pp.265-276
• /
• 1999

Video on Demand (VOD) system is definitely one of main applications in upcoming multimedia era. In this research, we have designed and implemented a host-based scalable VOD system (SVOD) which is composed of low cost PC servers and runs on Linux kernel that is currently spotlighted in enterprise and research domains. Our contribution is as follows: first, the previous Ext2 file system was modified to efficiently support continuous media like MPEG stream. Second, the storage server features a host-based scalable architecture. Third, a software MPEG decoder was implemented using Microsoft's DirectShow$\circledR$COM. Finally, flow control between client and server is provided to suppress overflow and underflow of client circular buffer and supports FF VCR operation. We have known that it is possible to develop a thread-based and scalable VOD system on low cost PC servers and free Linux kernel.

• Journal of KIISE:Computer Systems and Theory
• /
• v.32 no.6
• /
• pp.296-305
• /
• 2005

TCP/IP, the most popular communication protocol, is processed on a host CPU in traditional computer systems and this imposes enormous loads on the host CPU. Recently TCP/IP Offload Engine (TOE) technology, which processes TCP/IP on a network adapter instead of the host CPU, becomes an important way to solve the problem. In this paper we analysed the structure of a TCP/IP protocol stack in the Linux operating system and important factors, which cause a lot of loads on the host CPU, by measuring the time spent on processing each function in the protocol stack. Based on these analyses, we propose a Hybrid TOE architecture, in which functions imposing much loads on the host CPU are implemented using hardware and other functions are implemented using software.

• International Journal of Internet, Broadcasting and Communication
• /
• v.14 no.3
• /
• pp.17-21
• /
• 2022

In this study, we wanted to examine the new vulnerability 'Dirty Pipe' that is founded in Linux kernel. how it's exploited and what is the limitation, where it's existed, and overcome techniques and analysis of the Linux kernel package. The study of the method used the hmark[1] program to check the vulnerabilities. Hmark is a whitebox testing tool that helps to analyze the vulnerability based on static whitebox testing and automated verification. For this purpose of our study, we analyzed Linux kernel code that is downloaded from an open-source website. Then by analyzing the hmark tool results, we identified in which file of the kernel it exists, cvss level, statistically depicted vulnerabilities on graph which is easy to understand. Furthermore, we will talk about some software we can use to analyze a vulnerability and how hmark software works. In the case of the Dirty Pipe vulnerability in Linux allows non-privileged users to execute malicious code capable of a host of destructive actions including installing backdoors into the system, injecting code into scripts, altering binaries used by elevated programs, and creating unauthorized user profiles. This bug is being tracked as CVE-2022-0847 and has been termed "Dirty Pipe"[2] since it bears a close resemblance to Dirty Cow[3], and easily exploitable Linux vulnerability from 2016 which granted a bad actor an identical level of privileges and powers.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.7
• /
• pp.65-73
• /
• 2022

Recently, as the Windows system supports the Windows subsystem for Linux (WSL), various researchers have studied to apply a docker container on various systems such as server systems, workstation system and so on. However, in various existing researchers, there is a lack of performance-related indicators to apply the system to each operating system (linux system and windows system). In this paper, we compared a performance comparison and analysis of container-based host operating systems. We configured experimental environments of operating systems for microsoft windows systems and linux systems based on a docker container support. In experimental results, the containers of linux systems reduced the average data latency of dataset 1-6 by 3.9%, 62.16%, 1552.38%, 7.27%, 60.83%, and 1567.2%, compared to the containers on microsoft windows systems.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2609-2611
• /
• 2003

In this study, we explain the process and the technique required for implementing web-based remote control system based on embedded processor, SAl110, and embedded Linux. At first. cross-compile environment for target system should be constructed on host computer, and bootloader in charge of Linux booting may be loaded on the target system. Then, kernel image is compiled and loaded on the target system. Embedded Linux porting process is completed when ram disk image is generated. Finally, we load wed-server and device driver on the ram disk and make web-page for remote control using CGI. Through the above process, we implement web-based remote control system and present the result.

• Journal of Information Processing Systems
• /
• v.4 no.4
• /
• pp.133-144
• /
• 2008

Clusters have become a popular alternative for building high-performance parallel computing systems. Today's high-performance system area network (SAN) protocols such as VIA and IBA significantly reduce user-to-user communication latency by implementing protocol stacks outside of operating system kernel. However, emerging parallel applications require a significant improvement in communication latency. Since the time required for transferring data between host memory and network interface (NI) make up a large portion of overall communication latency, the reduction of data transfer time is crucial for achieving low-latency communication. In this paper, Eager Data Transfer (EDT) mechanism is proposed to reduce the time for data transfers between the host and network interface. The EDT employs cache coherence interface hardware to directly transfer data between the host and NI. An EDT-based network interface was modeled and simulated on the Linux-based, complete system simulation environment, Linux/SimOS. Our simulation results show that the EDT approach significantly reduces the data transfer time compared to DMA-based approaches. The EDTbased NI attains 17% to 38% reduction in user-to-user message time compared to the cache-coherent DMA-based NIs for a range of message sizes (64 bytes${\sim}$4 Kbytes) in a SAN environment.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.2
• /
• pp.316-321
• /
• 2017

With the recent wide adoption of Linux in the fields of IoT, embedded, mobile, desktop and server industries, the importances of understanding the Linux system architecture as well as customizing the Linux system are increasing very steeply. Accordingly, the capabilities of building every component of Linux system from source code files have been important. The LFS (Linux From Scratch) site[1] guides the steps of building the basic Linux system from source files. The steps consist of build host preparation step, temporary system building step, final system building step, and system configuration and boot preparation step. However, the underlying concepts behind the steps used in building LFS are difficult to understand, particularly to the beginner. This paper analyzes the LFS build steps and reveal the core build concepts and principles used in each step. Additionally, this paper shows the measured package build times obtained from our build experience.

• Journal of the Institute of Convergence Signal Processing
• /
• v.6 no.4
• /
• pp.169-175
• /
• 2005

In recent, implementation of the embedded system is gradually in the spotlight of world-wide by information technology(IT) engineers. By this time, an implementation of real time system is limited on image acquisition and processing system in practical. In this paper, the USB camera interface system based on the embedded linux OS is implemented using USB 2.0 camera with low cost. This system can obtain image signals into the memory via X-hyper255B processor from USB camera. It is need to initialize USB camera by the Video4Linux for the kernel device driver. From the system image capturing and image processing can be performed. It is confirmed that the image data can be transformed to packet of Network File System(NFS) and connected to the internetwork, then the data can be monitored from the client computer connected to the internetwork.