[월:] 2016년 07월

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개발자를 위한 SSD (Coding for SSD) – Part 3 : 페이지 & 블록 & FTL(Flash Translation Layer)

2016-07-16 KENNETH 0

개발자를 위한 SSD (Coding for SSD) – Part 3 : 페이지 & 블록 & FTL(Flash Translation Layer) 이번 챕터에서는 데이터 쓰기가 Block과 Page 레벨에서 어떻게 처리되는지, 그리고 쓰기 시에 발생하는 “Write Amplication”과 “Wear Leveling”의 기본적인 개념을 살펴보도록 하겠다. 추가로 FTL(Flash Translation Layer)이 무엇인지, 그리고 FTL의 2가지 목적인 논리적 블록 맵핑(Logical Block Mapping, 여기에서는 Hybrid Log Block Mapping 위주로)과 Garbage-collection도 같이 살펴볼 것이다. 3. 기본 오퍼레이션 3.1. 읽기 & 쓰기 & 삭제(Erase) NAND 플래시 메모리의 구성 특성상, 특정 셀을 단독으로 읽고 쓰는 작업은 불가능하다. 메모리는 그룹핑되어 있으며, 아주 특별한 방법으로만 접근할 수 있다. 그래서 NAND 플래시 메모리의 특별한 방법을 숙지하는 것은 SSD의 데이터 구조를 최적화하고 작동 방식을 이해하는데 있어서 꼭 필요한 부분이다. 이번 섹션에서는 SSD의 읽고 쓰기 그리고 삭제(Erase) 오퍼레이션이 실행되는 방법들을 살펴 보도록 하겠다. 읽기는 페이지 사이즈 단위로 실행(Reads are aligned on page size) 한번에 하나의 페이지보다 작은 크기의 데이터를 [ more… ]

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USN-3034-1: Linux kernel vulnerability

2016-07-15 KENNETH 0

USN-3034-1: Linux kernel vulnerability Ubuntu Security Notice USN-3034-1 14th July, 2016 linux vulnerability A security issue affects these releases of Ubuntu and its derivatives: Ubuntu 14.04 LTS Summary The system could be made to crash under certain conditions. Software description linux – Linux kernel Details Jan Stancek discovered that the Linux kernel's memory manager did notproperly handle moving pages mapped by the asynchronous I/O (AIO) ringbuffer to the other nodes. A local attacker could use this to cause adenial of service (system crash). Update instructions The problem can be corrected by updating your system to the following package version: Ubuntu 14.04 LTS: linux-image-3.13.0-92-powerpc-e500mc 3.13.0-92.139 linux-image-3.13.0-92-powerpc-e500 3.13.0-92.139 linux-image-3.13.0-92-powerpc64-smp 3.13.0-92.139 linux-image-3.13.0-92-generic-lpae 3.13.0-92.139 linux-image-3.13.0-92-powerpc-smp 3.13.0-92.139 linux-image-3.13.0-92-lowlatency 3.13.0-92.139 linux-image-3.13.0-92-generic 3.13.0-92.139 linux-image-3.13.0-92-powerpc64-emb 3.13.0-92.139 To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades. After a standard system update you need to reboot your computer to makeall [ more… ]

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USN-3034-2: Linux kernel (Trusty HWE) vulnerability

2016-07-15 KENNETH 0

USN-3034-2: Linux kernel (Trusty HWE) vulnerability Ubuntu Security Notice USN-3034-2 14th July, 2016 linux-lts-trusty vulnerability A security issue affects these releases of Ubuntu and its derivatives: Ubuntu 12.04 LTS Summary The system could be made to crash under certain conditions. Software description linux-lts-trusty – Linux hardware enablement kernel from Trusty for Precise Details USN-3034-1 fixed a vulnerability in the Linux kernel for Ubuntu 14.04LTS. This update provides the corresponding updates for the LinuxHardware Enablement (HWE) kernel from Ubuntu 14.04 LTS for Ubuntu12.04 LTS. Jan Stancek discovered that the Linux kernel's memory manager did notproperly handle moving pages mapped by the asynchronous I/O (AIO) ringbuffer to the other nodes. A local attacker could use this to cause adenial of service (system crash). Update instructions The problem can be corrected by updating your system to the following package version: Ubuntu 12.04 LTS: [ more… ]

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USN-3035-1: Linux kernel vulnerability

2016-07-15 KENNETH 0

USN-3035-1: Linux kernel vulnerability Ubuntu Security Notice USN-3035-1 14th July, 2016 linux vulnerability A security issue affects these releases of Ubuntu and its derivatives: Ubuntu 15.10 Summary The system could be made to crash under certain conditions. Software description linux – Linux kernel Details Jan Stancek discovered that the Linux kernel's memory manager did notproperly handle moving pages mapped by the asynchronous I/O (AIO) ringbuffer to the other nodes. A local attacker could use this to cause adenial of service (system crash). Update instructions The problem can be corrected by updating your system to the following package version: Ubuntu 15.10: linux-image-4.2.0-42-powerpc64-smp 4.2.0-42.49 linux-image-4.2.0-42-generic 4.2.0-42.49 linux-image-4.2.0-42-generic-lpae 4.2.0-42.49 linux-image-4.2.0-42-powerpc64-emb 4.2.0-42.49 linux-image-4.2.0-42-powerpc-e500mc 4.2.0-42.49 linux-image-4.2.0-42-lowlatency 4.2.0-42.49 linux-image-4.2.0-42-powerpc-smp 4.2.0-42.49 To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades. After a standard system update you need to reboot your computer to makeall the necessary changes. ATTENTION: [ more… ]

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USN-3035-2: Linux kernel (Raspberry Pi 2) vulnerability

2016-07-15 KENNETH 0

USN-3035-2: Linux kernel (Raspberry Pi 2) vulnerability Ubuntu Security Notice USN-3035-2 14th July, 2016 linux-raspi2 vulnerability A security issue affects these releases of Ubuntu and its derivatives: Ubuntu 15.10 Summary The system could be made to crash under certain conditions. Software description linux-raspi2 – Linux kernel for Raspberry Pi 2 Details Jan Stancek discovered that the Linux kernel's memory manager did notproperly handle moving pages mapped by the asynchronous I/O (AIO) ringbuffer to the other nodes. A local attacker could use this to cause adenial of service (system crash). Update instructions The problem can be corrected by updating your system to the following package version: Ubuntu 15.10: linux-image-4.2.0-1034-raspi2 4.2.0-1034.44 To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades. After a standard system update you need to reboot your computer to makeall the necessary changes. ATTENTION: Due to an unavoidable ABI [ more… ]