20140712

1. cacloud02, 08번 오류 해결 중.
cacloud02번은 아직도 원인을 파악하지 못했다.
cacloud08의 /var/log/xen 아래 로그를 모두 지운 다음에, 새로 들어오는 로그만 분석해보았다.

... xs_read(): vncpasswd get error
...
qemu...
...

아래 링크의 상황이 가장 비슷해 보였다.
Link : xen hvm starts but does not create vnc and there is no state status from xm list, http://community.spiceworks.com/topic/101417-xen-hvm-starts-but-does-not-create-vnc-and-there-is-no-state-status-from-xm-list

네트워크 설정 도중에 cacloud08이 꺼져버림.


2. DRAM 공부
1) IBM, 1996, Applications Note (Understanding DRAM Operation)
다소 오래된 문서이지만, DRAM의 기본적인 동작에 대해 정말 깔끔하게 잘 정리되어 있다.

2) Eye diagram에 대해 이해.
DRAM에 대해 찾아볼 때마다 이상한 그래프가 나와서 ‘뭐지?’ 하고 넘어갔는데, eye diagram이라고 한다.


(http://www.edn.com/design/test-and-measurement/4389368/Eye-Diagram-Basics-Reading-and-applying-eye-diagrams)

What does it show?

Eye diagrams show parametric information about the signal– effects deriving from physics such as system bandwidth

health, etc. It will not show protocol or logical problems – if a logic 1 is healthy on the eye, this does not reveal the fact that the system meant to send a zero. However, if the physics of the system mean that a logic one becomes so distorted while passing through the system that the receiver at the far end mistakes it for a zero, this should be shown in a good eye diagram.

Common ways of characterizing an eye are to measure the rise times, fall times, jitter at the middle of the crossing point of the eye, the overshoot present and many other numerical descriptions of eye behavior in order to compare devices being measured. Instruments usually offer automated measurements that simplify and speed up the taking of such measurements.

References :
[1] Deepak Behera, Sumit Varshney, Sunaina Srivastava, and Swapnil Tiwari, Freescale Semiconductor, (2011.12.16), Eye Diagram Basics: Reading and applying eye diagrams, EDN, http://www.edn.com/design/test-and-measurement/4389368/Eye-Diagram-Basics-Reading-and-applying-eye-diagrams
[2] Bruce Jacob,Spencer Ng,David, Memory Systems: Cache, DRAM, Disk
[3] Anatomy of an Eye Diagram, Tektronix, http://www.tek.com/application-note/anatomy-eye-diagram

3) HBM
[1] Wide I/O 2에서 HBM, 차세대 메모리가 나온 Memcon 2012, gigglehd, http://gigglehd.com/zbxe/newsreport/8501042
[2] 테라바이트 대역의 차세대 메모리 HBM, 2015년에 등장, gigglehd, http://gigglehd.com/zbxe/newsreport/9626135
[3] 차세대 GPU 메모리, HBM DRAM이 양산 단계,gigglehd, http://gigglehd.com/zbxe/newsreport/11406988
[4] TSV 적층, GDDR5의 후계자 HBM의 정보, gigglehd, http://gigglehd.com/zbxe/11424525
[5] 8Gb 투입으로 대용량화를 도모하는 HBM의 로드맵, gigglehd, http://gigglehd.com/zbxe/newsreport/11469149


3. DRAM에 대해 찾다보니 application note라는 것이 많이 나온다. Application note가 무엇인가?


4. SPEC benchmark를 실행하는 방법에 대해 공부해야 함.
SPEC benchmark 압축을 해제하고, install.sh, shrc는 실행했으나, runspec을 실행할 수 없었다.


5. 마음에 드는 글 몇 개 스크랩.
[1] scratch와 kodu, babyworm, http://babyworm.net/wordpress/?p=1803
[2] 오랜 시간 일하는 것이 좋은 것일까, babyworm, http://babyworm.net/wordpress/?p=1797

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