In research sometimes you want to make a movie from single images, like plots from experimental data or from calculation to visualize changes or so on. In order to achieve this you can use ffmpeg. First you have to create the images and save them, where the images need to have a continuous number in [...]
If you have your own Ubuntu server running you may encounter the maximal file size upload limit in php scripts which is set to 2Mb as default. In order to change that we first have a look what the size actually is. In /var/www (standard www directory) create a file called info.php with the following [...]
There is a new beta version of VirtualBox for Mac OS X available and installing Ubuntu Gutsy Gibbon worked like a charm (in opposition to Parallels). The only problem I encountered was, that it was not possible to mount a directory from the Mac OS X host in the guest system with either the internal [...]
Some months ago I wrote a small Howto about installing Gnuplot on Ubuntu Feisty Fawn with readline, pdf and wxWidgets terminal support. It turned out, that this howto was of interest for many people, since this blog post was the most visited until Gutsy Gibbon came out - and the readline problem was obviously solved, [...]
I use an Ubuntu server as a work-horse for my calculations and connect from my desktop-pc with ssh to the server. For some applications (gnuplot =) this is really slow altough it’s over LAN. I found on the internet some instructions to improve this situation: instead of the AES cipher the arcfour and blowfish ciphers [...]
Yesterday I wrote that my swap partition suddenly vanished, only to find out that suddenly my swap partition was mounted twice. “top” showed twice the amount of swap space available and “cat /proc/swaps” listed two entries to the same swap partition (/dev/sda6 and /dev/mapper/sda6). This seems to be a bug in Ubuntu Feisty and the [...]
When checking ‘top’ after I was told that I have no memory anymore I found out that I had no swap drive anymore. Must have gone lost when I switched to Ubuntu Feisty. Anyway, I found a description to re-initiate the swap drive:
First find out which partition your swap drive is, e.g. with ’sudo fdisk [...]
I kept getting these error message during the boot process and also after issuing the command ’sudo update-initramfs -u’:
W: mdadm: unchecked configuration file: /etc/mdadm/mdadm.conf
W: mdadm: please read /usr/share/doc/mdadm/README.upgrading-2.5.3.gz .
W: mdadm: no arrays defined in configuration file.
W: mdadm: falling back to emergency procedure in initramfs.
The mdadm-package is needed for software raid array. If you don’t have [...]
Though you can usually install most programs in Linux comfortably with the package manager of you Linux distribution (rpm, deb, etc.), sometimes you need to compile something from source.
For example gnuplot in Debian/Ubuntu has the readline functionality not compiled in, which makes it rather hard to use. But I’m somewhat reluctant to install these programs [...]
I installed today Ubuntu Server Edition 7.04 on one of my machines and here practically nothing is installed. Therefore for example X11 forwarding doesn’t work if you remotely log in with “ssh -X” (after you installed openssh-server :). So, if you start a X11 program you get e.g.:
xterm Xt error: Can’t open display:
xterm: DISPLAY [...]
