구차니의 잡동사니 모음

$ sudo apt-get update; sudo apt-get upgrade

기존:1 http://ppa.launchpad.net/saiarcot895/myppa/ubuntu xenial InRelease

기존:2 http://ports.ubuntu.com/ubuntu-ports xenial InRelease

기존:3 http://ports.ubuntu.com/ubuntu-ports xenial-updates InRelease

기존:4 http://ports.ubuntu.com/ubuntu-ports xenial-backports InRelease

기존:5 http://ports.ubuntu.com/ubuntu-ports xenial-security InRelease

패키지 목록을 읽는 중입니다... 완료

E: /var/lib/dpkg/lock 잠금 파일을 얻을 수 없습니다 - open (11: Resource temporarily unavailable)

E: 관리 디렉터리를 (/var/lib/dpkg/) 잠글 수 없습니다. 다른 프로세스가 사용하고 있지 않습니까? 

~$ ps -ef | grep apt

root      2471     1  0 12:42 ?        00:00:00 /bin/sh /usr/lib/apt/apt.systemd.daily update

root      2475  2471  0 12:42 ?        00:00:00 /bin/sh /usr/lib/apt/apt.systemd.daily lock_is_held update

root      3743     1  0 12:45 ?        00:00:00 /bin/sh /usr/lib/apt/apt.systemd.daily install

$ sudo systemctl stop apt-daily.timer

$ sudo systemctl disable apt-daily.timer

$ sudo systemctl mask apt-daily.service

$ sudo systemctl daemon-reload 

/usr/lib/apt/apt.systemd.daily 

$ sudo vi /etc/apt/apt.conf.d/10periodic

APT::Periodic::Enable "0";

Systemd is all about concurrent start of services, so the cloud-init script is run at the same time the apt-daily.service is triggered. By the time cloud-init gets to execute the user-specified payload, apt-get update is already running. So the attempts 2. and 3. failed not because of some namespace magic, but because they altered the system too late for apt.systemd.daily to pick the changes up.

This also means that there is basically no way of preventing apt.systemd.daily from running -- one can only kill it after it's started. 

Ultra High Speed, Phase I (UHS-I) bus design for SDHC and SDXC cards was added in SD spec 3.0. This is a design enhancement to increase the performance of SDHC/SDXC cards.

There is no compatibility problem using a UHS card with a non-UHS device. 

Ultra High Speed Phase II (UHS-II) bus design for SDHC and SDXC was added in SD spec 4.0. This is an additional design enhacement with connector interface modifications to increase performance.

UHS-II specification defines bus architecture for options of 156MB/s and 312MB/s. Manufacturers implemented the 312MB/s option in memory cards. These are theoretical maximum limits and actual maximum performance for a specific card is defined on the label or in advertising.

Host devices will obtain the maximum UHS-II speed when both the card and the host device support UHS-II. Otherwise, the host device and card will use the highest compatible UHS-I or SD bus speed.

There is no compatibility problem using a USH-II card in a UHS-I or non-UHS device.

UHS라는 말이 혼용돼 쓰이기 때문에 조금 헷갈릴 수 있습니다. UHS-I, UHS-II 등은 SD카드의 버스 규격입니다. 파일을 주고 받을 수 있는 틀이라고 보면 됩니다. 그리고 이는 다시 U1, U3 등으로 나뉩니다. 이는 ‘UHS 스피드 클래스’라고 부릅니다. U1은 초당 최소 10MB, U3는 30MB를 쓸 수 있다는 표기입니다. 클래스와 비슷하다고 보면 됩니다.

현재 나오는 제품들은 거의 UHS-I 버스를 씁니다. 그리고 플래시메모리에 따라 실제 속도는 U1과 U3 정도로 나뉜다고 보면 됩니다. 4K 영상을 찍으려면 U3 정도 속도가 필요하고, 풀HD라면 클래스10, 혹은 U1이라고 표기된 제품이면 됩니다. 

Supports next-generation memory cards including SDHC UHS-I, SDXC UHS-I, micro SDHC UHS-I, micro SDXC UHS-I 

$ sudo nano /etc/modprobe.d/mk_arcade_joystick_rpi.conf

options mk_arcade_joystick_rpi map=5 gpio=2,3,4,17,9,10,22,27,11,24,23,25 

$ sudo apt-get install cmake

$ git clone https://github.com/tasanakorn/rpi-fbcp

$ cd rpi-fbcp/

$ mkdir build

$ cd build/

$ cmake ..

$ make

$ sudo install fbcp /usr/local/bin/fbcp

$ sudo apt-get install fbset

$ con2fbmap 1 1