Ben Struthers

IMPROVING PERFORMANCE OF RADEON CARDS AND UBUNTU 9.04

While messing around with my laptop, I noticed that changing wallpaper was painfully slow due to the poor performance of my laptop's Radeon 9000 mobility card. Doing a little research led me to this link.

Following the steps in the link greatly improved my card's performance. A must if you want to run any of the Compiz Visual Effects, watch "CoCo" O'Brien on Hulu, or, really... do just about anything.

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FIXING LOW BANDWIDTH ISSUE W/ RT2X00 AND UBUNTU 9.04

There's currently a bug in Ubuntu 9.04 causing rt2x00 based wireless cards to have their bit rate set at 1 Mb/s. This in turn causes bandwidth to hover around 40 Kb/s. In the past I've manually installed the serial monkey drivers but this time I wanted to still use the NetworkManager applet so I could vpn into my home network. The fix for the issue was surprisingly simple:

ben@Akula:~$ sudo apt-get install linux-backports-modules-jaunty

After installing the backports, I simply rebooted my pc and my card's bit rate was set to where it belongs - 54 Mb/s. Finally, I can surf at full speed without having to set the bit rate manually!

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REMOVING OLD KERNELS FROM UBUNTU

Run the below command to see what kernels are installed.

ben@Akula ~ $ dpkg -l '*image*' | grep ^ii

Run the below command to remove the unwanted entries.

ben@Akula ~ $ sudo apt-get --purge remove <name of kernel image>

*MAKE SURE YOU DON'T REMOVE THE RUNNING KERNEL!!!*

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GETTING STARTED WITH LEJOS & UBUNTU 8.10

First download and extract the latest leJOS release. You can find the files here: leJOS Releases

If you don't have the latest Java JDK installed, open a new terminal and install it now.

ben@Akula ~ $ sudo apt-get install sun-java6-jdk

Now install ant, libusb-dev, & libbluetooth-dev

ben@Akula ~ $ sudo apt-get install ant libusb-dev libbluetooth-dev

The next step is to create an environment variable named NXJ_HOME that points to where you extracted the latest leJOS release and to append the lejos_nxj/bin directory to your PATH. Fire up your favorite text editor

ben@Akula ~ $ sudo nano ~/.bashrc

and add the following:

export NXJ_HOME="$HOME/development/lejos_nxj" # Path to lejos
export PATH="$PATH:$NXJ_HOME/bin"

Restart the terminal and check to make sure the NXJ_HOME & PATH variables are set.

ben@Akula ~ $ echo $NXJ_HOME
ben@Akula ~ $ echo $PATH

You should see something similar to this

/home/ben/development/lejos_nxj

and this

/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/bin/X11:/usr/games:/home/ben/development/lejos_nxj/bin

With the environment variables set, cd into the leJOS build directory

ben@Akula ~ $ cd $NXJ_HOME/build

Run ant to build leJOS

ben@Akula ~/development/lejos_nxj/build $ ant

Before you can flash your NXT, you'll need to add a udev rule to allow your account access to /dev/usb. I created a group named lego and added my user account to it. If you do this, you may need to log off and log back in.

Now fire up your favorite text editor

ben@Akula ~ $ sudo nano /etc/udev/rules.d/70-lego.rules

and add the following:

# Lego NXT (Make sure you set the group to what you want)
BUS=="usb", SYSFS{idVendor}=="03eb", GROUP="lego", MODE="0660"
BUS=="usb", SYSFS{idVendor}=="0694", GROUP="lego", MODE="0660"

With the rules created, restart udev so they take effect

ben@Akula ~ $ sudo /etc/init.d/udev restart

Test that the new rules are in place and try to flash your NXT

ben@Akula ~ $ nxjflash

That's it! Follow "Compiling and running your first code" in the leJOS README.html and be sure to run through the tutorials on the leJOS site.

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