Karmic HOWTO

Posted on October 16, 2009

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Installing Crunchbang

Gather the necessary components:

Next, install a command line system:

  1. Follow the steps detailed at unetbootin for creating a bootable USB flash drive using the mini.iso downloaded earlier.
  2. Plug your USB drive into your Aspire One, plug in your ethernet cable and boot.
  3. Press F12 when the BIOS screen comes up and select your flash drive.
  4. Select “Command-line expert install’.
  5. Follow the installation prompts. I deviated from the defaults in partitioning and when asked about security updates. For the former, I created 5GB “/” and 11GB “/home” ext2 partitions with the “noatime” option ticked. (If your AAO does not have an SSD then you should create a swap partition and use a more advanced file system like the new Ubuntu default ext4.) For the latter, I chose to let the system automatically install security updates.

Now we can boot into our new system and install Crunchbang Linux. Since Crunchbang 9.10.01 is still under development, we will use the 9.04.01 installation script.

wget http://crunchbanglinux.org/build-scripts/crunchbang-installer-9.04.01.sh
sudo sh crunchbang-installer-9.04.01.sh

Type your password, answer “y” to install Crunchbang Linux, select your installation type (“desktop” or “lite”) and answer “y” when prompted about installing the medibuntu keyring. When the installation in nearly complete you will be asked whether or not to use “network-manager” to manage your internet connections. I selected “n” because I prefer to use “wicd”. If you would like to install “wicd”:

sudo aptitude install wicd

Congratulations! You now have Crunchbang Linux installed!

SSD optimization

Since I have an SSD, I’d like to minimize writes to it as well as speed up its performance somewhat.

Optimizing the performance of your SSD under Karmic is slightly different than under Jaunty. First, it no longer seems to be possible to mount /var/tmp as tmpfs. Second “unionfs” seems to have been dropped in favor of “aufs” (at least my unionfs entries in /etc/fstab no longer seem to work). So the first step is to put /tmp into RAM. To do so add:

tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0

to the end of /etc/fstab.

Next, I also want to put /var/log and /var/cache into RAM. To do so, I now use “aufs” to unite /tmp and /var/log and to unite /tmp and /var/cache. The advantage of using “aufs” is that the existing directory structure is preserved so that it does not need to be recreated using a script. I also unite /tmp and /var/tmp since tmpfs no longer appears to be an option. To make these changes, add:

none /var/tmp aufs noatime,br:/tmp=rw:/var/tmp=ro 0 0
none /var/log aufs noatime,br:/tmp=rw:/var/log=ro 0 0
none /var/cache aufs noatime,br:/tmp=rw:/var/cache=ro 0 0

to the end of /etc/fstab.

The next SSD optimization I applied is to add either “elevator=noop” or “elevator=deadline” to the line that starts “GRUB_CMDLINE_LINUX_DEFAULT” of /etc/default/grub, e.g.,

GRUB_CMDLINE_LINUX_DEFAULT=”elevator=noop quiet splash”

Now run ’sudo update-grub2’. The various ‘elevator’ kernel options specify the order in which writes are made to a disk. This is important for traditional hard drives where the write head moves along the platter and writing sequentially according to the direction the write head is moving will improve performance. But with an SSD, there is no write head so that specifying a particular order for writes can actually degrade performance. The ‘elevator=noop’ kernel option disables this, improving SSD speed.

Firefox on an SSD

Firefox by default caches data to the hard drive. This is no good for an SSD but it can be fixed by telling Firefox to cache data in /tmp. To do so, open Firefox and type ‘about:config’ in the browser window. Click ‘I’ll be careful, I promise!’ and then create (or edit) the key ‘browser.cache.disk.parent_directory’ and give it the value ‘/tmp’.

Fan speed management

Fan management by the Aspire One’s bios sucks. To fix this, use the acerhdf kernel module that ships with Karmic. While it is automatically loaded at boot, it is not enabled. To enable it type:

sudo -s
echo -n “enabled” > /sys/class/thermal/thermal_zone0/mode
^D

To automatically enable it at boot, create “/etc/modprobe.d/acerhdf.conf” and add the line:

options acerhdf kernelmode=1

You can also change the default parameters by replacing “kernelmode=1” with one or more of “interval=<num1>”, “fanon=<num2>” and “fanoff=<num3>” where <num1> is the frequency (in seconds) with which  the temperature should be checked (default=10), <num2> is the temperature (in Celsius) at which the fan should come on (default=67) and <num3> is the temperature at which the fan should shut off (default=62). Unless you know what you are doing, leave these on the default as poorly chosen parameters can seriously damage your computer.

Wireless

Wireless and the wireless LED appear to work out-of-the-box.

Sound

Sound, including the built-in mic, seem to work with Skype.

Card readers

I have only been able to test the card readers using an SD card since that is all I have.

The left hand card reader is hot-swapable out-of-the-box. The right hand card reader is hot-swapable after adding “pciehp.pciehp_force=1” to the line reading “GRUB_CMDLINE_LINUX_DEFAULT”. If you added the “elevator=noop” line then it should now read

GRUB_CMDLINE_LINUX_DEFAULT=”pciehp.pciehp_force=1 elevator=noop quiet splash”

Now run:

sudo update-grub2

to make the changes take effect.

Update 11/12/09: Reader phh points out that SDHC cards cause problems with suspend which can be fixed with a suspend script (see https://bugs.launchpad.net/ubuntu/+source/linux/+bug/424877).

Fixes for Crunchbang Linux

Since Crunchbang 9.10.01 does not have an install script yet, there are a couple of issues that need to be tweaked. First of all, the “openbox-logout” script does not work with gdm 2.28.0. Instead I followed the instructions here. In order to minimize the number of files that would need to be modified, I put urukrama’s script in /usr/bin/openbox-logout  (you can preserve the original if you wish with “sudo cp /usr/bin/openbox-logout /usr/bin/openbox-logout-orig”).

The second issue is that usplash seems to throw an error. At this point I do not have a fix for it but the system is fully functional. I will update this when I have a fix.

Reboot into your new system!

Google chrome

I love my AAO but let’s face it. The AAO is no powerhouse and at times firefox can be pretty slow on it. On my AAO, google-chrome-beta is now my default web browser. While it is lacking in nice extensions, it is very snappy on my AAO. To install it, go here and accept Google’s terms to download the package. Open a terminal window and

sudo dpkg -i /path/to/google-chrome-unstable_current_i386.deb

You can now run Google Chrome by typing “google-chrome &”. At the moment, there does not appear to be any way to direct Google Chrome to use /tmp for it’s caching.

Update 12/16/09: The cache is in “~/.cache/google-chrome” and can be put in /tmp the same way we put /var/log and /var/cache in /tmp. It’s a little kludgie but it works. To do so, add:

none /home/tct/.cache/google-chrome aufs noatime,br:/tmp=rw:/home/<username>/.cache/google-chrome=ro 0 0

to the end of /etc/fstab.

To make google-chrome your default web browser you need to edit two files. Type “gedit .config/openbox/menu.xml” and change every instance of “firefox” to “google-chrome”. Do the same for “.config/openbox/rc.xml”. You will need to restart openbox for these changes to take effect.

Concluding remarks

Please comment if you have questions or problems. I plan to update this HOWTO as Karmic and Crunchbang 9.10.01 develop.

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