Richi's blog

Tag: linux

  • Screen went black

    This morning, I had a short moment of horror when I turned on my Netbook. After the ubuntu splash screen, it went black and didn’t respond to any keys. The only response was for the power key, where it displayed the ubuntu splash screen again and shut down.

    My Acer aspire one has the dreaded Intel gma500 poulsbo graphics card. This graphics chipset was bought by Intel, and it’s absymal driver support has embarassed them ever since. It is also the reason I still run maverick on the netbook. Knowing that, I was even more horrified by the screen turning black.

    First thing was trying to boot an older kernel. In case you’re not presented with a grub menu, press shift after the BIOS.  Didn’t help, not even in recovery mode.

    So I booted to a console, and examined

    $cat /var/log/apt/history.log | tail

Start-Date: 2012-01-24  21:15:04
Commandline: apt-get install python-pyopencl
Install: nvidia-current:i386 (260.19.06-0ubuntu1, automatic), nvidia-settings:i386 (260.19.06-0ubuntu1, automatic), python-pyopencl:i386 (0.92~beta+git20100709-1ubuntu1), python-pytools:i386 (10-7, automatic), python-decorator:i386 (3.2.0-1, automatic)
End-Date: 2012-01-24  21:20:26

    The only thing I installed yesterday was python-pyopencs as it was the only package in the repository that seemed like a starting point to experiment with OpenCL. It has dependencies to nvidia drivers, but I didn’t think that installing these would break my system.

    So, all I had to do was “apt-get purge python-pyopencs nvidia-current nvidia-settings” and the system would boot again normally.

    It’s amazing how a linux system that doesn’t boot can almost always be saved relatively easily. With a Windows system that has the same symptoms you’re fucked.

  • Running debian on a nas dongle [updated]

    I used a nas dongle from ARP for a while to share an USB harddisk, and I always wondered about what’s inside. It’s a nifty little device that works reasonably well. It needed a reboot from time to time, and it had some issues with the filesystem. Because of the FAT filesystem it couldn’t store large files, but what I missed most was ssh. Not ssh itself, but scp, sftp and rsync. I knew that without further information it would be impossible to add these. But so far I couldn’t find out anything on the internet. Then somehow I found a blog post with a device that looked similar from the outside but was sold more like a hacker device. So I went to figure out if it’s the same. It looked similar from the inside as well. So, it is probably really a bifferboard. The pins for the serial console matched, which was even more proof…

    The boot messages with the stock firmware look like this:  $ minicom -b 115200 -D /dev/ttyUSB0

    (more…)

  • missing env variables when running from cron

    Today I solved another problem that bugged me for a while. Namely, I wanted to run the free flight prediction runs automatically from cron. When I ran it from the commandline or a script, it worked well, but when I tried to run it directly or through the same script from cron, it always failed with the following message : “critical error : basic_string::_S_construct NULL not valid”

    (more…)