Author Archive

Playing the Simpsons Theme on an Arduino

February 28th, 2016 No comments

A little while back, I picked up an Arduino Starter Kit. It contains an Arduino Uno, a bunch of common components, and an instruction book that walks beginners through building circuits and using the Arduino to interact with hardware.

One of the projects in the book is a basic synthesizer that lets you play tones on a piezo speaker. The schematic for this is dead simple:


After getting the Arduino to play a few notes, I decided to extend the project a bit and play a melody. After a bit of screwing around, I managed to get the thing to play the Simpsons theme.

The code for this sketch can be found on GitHub.

This article was originally posted at

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.
Categories: Arduino, Jon F Tags:

Installing ROS on a Raspberry Pi

February 21st, 2016 No comments

As a lover of technology, I tend to accumulate bits and pieces of interesting devices. Usually, these are purchased for use on unrelated projects, and on occasion, I have the opportunity to bring them together into a single project in a previously unanticipated way. Such is the case with my Arduino and Raspberry Pi. Both are interesting microcomputers with their own strengths and weaknesses, so it was when I learned that they could be made to work together with the help of Robot Operating System, I had to give it a shot.

My raspberry pi

ROS is an open-sourced project that is dedicated to providing a framework of libraries for performing common tasks under the general heading of robotics. It also includes drivers that allow you to easily interface with common hardware. The core of ROS is a reactor model of observables and observers that send messages to one another, typically over a serial connection, allowing any number of controllers to interface with one another and form a unified whole.

The rosserial_arduino library is a project that allows ROS on a Raspberry Pi (or other *nix device) to interface with an Arduino over a USB serial connection, thereby combining the computing power and versatility of a Linux-based microcomputer with the IO capabilities of an Arduino.

What You’ll Need to Get Started

Installing Raspbian on the Pi

If your Pi already has an operating system on it, you can probably skip this step. If, however, it’s straight out of the box, you’ll need to install the Raspbian distribution.

As of this writing, the latest version of Raspbian is Jesse, released in September of 2015. I wasn’t able to get ROS working with this version, and backed down to the Wheezy release from May of 2015 instead. To install the operating system, I did the following:

  1. Download the Raspbian Wheezy image via a bittorrent client.
  2. When the download is complete, follow these instructions to copy the image file to your MicroSD card.
  3. Unmount the card, insert it into your Pi, and hook up the power. Your device should boot into a command prompt. From here, you can run raspi-config to customize the installation, or get right to installing ROS.

Once the installation is complete, be sure to check for updates:

pi@raspberrypi ~ $ sudo apt-get update
pi@raspberrypi ~ $ sudo apt-get upgrade

An up to date system is a safe system.


Once your Pi has an operating system, you can switch to interacting with it via SSH. My TV is the only “monitor” in my house that has an HDMI input on it, so SSH works much better for me.

Make sure that sshd is running on your Pi:

pi@raspberrypi ~ $ sudo service sshd status
● ssh.service - OpenBSD Secure Shell server
 Loaded: loaded (/lib/systemd/system/ssh.service; enabled)
 Active: active (running) since Thu 2015-10-08 12:17:06 UTC; 4 days ago
 Main PID: 506 (sshd)
 CGroup: /system.slice/ssh.service
 └─506 /usr/sbin/sshd -D

If everything is working, you should see the text active (running) in the result. Once we know that an ssh server is running, we can check our ip address with the ifconfig command. The output should look something like this:

pi@raspberrypi ~ $ ifconfig
eth0      Link encap:Ethernet  HWaddr b8:27:eb:b9:49:cd  
          inet addr:  Bcast:  Mask:
          RX packets:5150 errors:0 dropped:51 overruns:0 frame:0
          TX packets:565 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:552488 (539.5 KiB)  TX bytes:60766 (59.3 KiB)

lo        Link encap:Local Loopback  
          inet addr:  Mask:
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:8 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1104 (1.0 KiB)  TX bytes:1104 (1.0 KiB)

If your Pi is connected to a LAN cable, you’ll want to look at the eth0 section. If it’s connected to WiFi, look for a wlan0 section. Both sections should have an inet addr field whose value starts with a 192.168.x.x address. In my case, it’s From a terminal on my computer, I can connect with:

jfritz@IDEAPAD-UBUNTU:~$ ssh pi@

When prompted to accept the Pi’s RSA key, I do, and when prompted for a password, I enter the default password raspberry. If you intend to leave the Pi connected to your network for long periods of time, you should change this password or add key-based authentication to the system.

If you have problems getting connected, check out the official instructions on the Raspberry Pi website.

Installing ROS on the Pi

As of this writing, the most recent version of ROS is Indigo, released in July of 2014. To get it running on the Pi, you’ll want to follow the official ROSberryPi installation instructions on the ROS website.

While following these instructions, I had a few false starts. It’s important to read the instructions carefully, as they’re fairly generic, and can be used to install different configurations of ROS on different versions of Raspbian. I found that the instructions for the ros_conn configuration worked best on Raspbian’s Wheezy release.

The  trickiest part of the instructions is section 2.2 Resolve Dependencies. It took me a couple of reads to realize that if you’re installing ROS Indigo’s ros_conn configuration on Raspbian Wheezy, you only need to compile two packages from source: libconsole-bridge-dev and liblz4-dev. Installing any other packages at this step just costs you time, and may introduce problems down the road.

I also found that the install process went much smoother when the Pi was connected to a LAN rather than WiFi. The WiFi signal in my house is relatively weak, and the Realtek #814B is really cheap, so downloading a lot of files while maintaining an SSH connection is a big ask.

Once the installation is complete, open up your ~/.bashrc file, and add two lines to the end:

# export ROS environment variables
source /opt/ros/indigo/setup.bash

This will make sure that the appropriate environment variables are set to interact with ROS on every startup. You can check that it worked by rebooting your Pi and running

pi@raspberrypi ~ $ printenv | grep ROS

If you see all of the ROS_* environment variables print out, then everything is set up and ready to go. Now it’s time to start on some tutorials.

Eventually, I want to get the Raspberry Pi communicating with the Arduino, and use the latter as a sensor platform and motor controller for some kind of a robot. For now, I need to find my way around ROS.

This article originally appeared at

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.

Cloud Saves for Minecraft

February 21st, 2014 No comments

I’ve recently become addicted to Minecraft. I realize that I’m late to this game, having only recently discovered it despite its popularity over the past couple of years. As readers know, I typically switch between a few different machines throughout my day, and indeed between a few different operating systems. Luckily, Minecraft is portable and can be played on any platform – but how to go about transferring saved games?

By default, Minecraft puts your user data and game saves in a hidden folder within your home folder. In particular, save game data is stored at ~/.minecraft/saves/. My solution to the cloud save problem was to create a minecraft folder in my DropBox, and then symlink the default save folder to this location.

Start by creating a folder in your DropBox (or other cloud share platform) folder:

jonf@UBUNTU:~$ mkdir ~/Dropbox/minecraft
jonf@UBUNTU:~$ mkdir ~/Dropbox/minecraft/saves

Next, back up your existing save games folder. We’ll restore these once the symlink has been created.

jonf@UBUNTU:~$ mv ~/.minecraft/saves/ ~/.minecraft/saves.old

Now create the symlink between the new DropBox folder and the save game location:

jonf@UBUNTU:~$ ln -s ~/Dropbox/minecraft/saves/ ~/.minecraft/saves
jonf@UBUNTU:~$ ls -la ~/.minecraft
total 24
drwxrwxr-x  3 jonf jonf  4096 Feb 21 08:58 .
drwx------ 43 jonf jonf 12288 Feb 21 08:55 ..
lrwxrwxrwx  1 jonf jonf    38 Feb 21 08:58 saves -> /home/jonf/Dropbox/minecraft/saves/
drwxrwxr-x  2 jonf jonf  4096 Feb 21 08:55 saves.old

As you can see, the saves folder under the .minecraft folder now points to the saves folder that we created inside of our DropBox folder. This means that if we put anything inside of that folder, it will be automatically written to the DropBox folder, which will be synced to all of my other computers.

Finally, let’s restore the existing saved games folder into the new shared folder:

jonf@UBUNTU:~$ mv ~/.minecraft/saves.old/ ~/.minecraft/saves

If I take the same steps on my other machines, then I can play Minecraft from any of my machines with my saved games always available, no matter where I am. Keep in mind that the ln syntax for Mac OSX is slightly different than the example above. The steps remain the same, but you’ll want to check the docs if you’re trying to adopt these steps for a different platform.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.

WTF Ubuntu

September 7th, 2013 2 comments

I’m not even sure what to say about this one… it looks like I might have an angry video card.

I sat down at my machine after it had been sitting for three or four days to find this... wtf?

I sat down at my machine after it had been sitting for three or four days to find this… wtf?

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.
Categories: God Damnit Linux, Jon F, Ubuntu Tags:

Dual Booting Ubuntu 13.04 and Windows 8 on a Lenovo Y400 IdeaPad

July 27th, 2013 1 comment

With the third edition of The Linux Experiment already underway, I decided to get my new laptop set up with an Ubuntu partition to work with over the next few months. A little while back, I purchased this laptop with intent to use it as a gaming rig. It shipped with Windows 8, which was a serious pain in the ass to get used to. Now that I’ve dealt with that and have Steam and Origin set up on the Windows partition, it’s time to make this my primary machine and start taking advantage of the power under its hood by dual-booting an Ubuntu partition for development and experiment work.

I started my adventure by downloading an ISO of the latest release of Ubuntu – at the time of this writing, that’s 13.04. Because my new laptop has UEFI instead of BIOS, I made sure to grab the x64 version of the distribution.

Aside: If you’re using NoScript while browsing Ubuntu’s website, you’ll want to keep an eye on the address bar while navigating through the download steps. In my case, the screen that asks you to donate to the project redirected me to a different version of the ISO until I enabled JavaScript.

After using Ubuntu’s Startup Disk Creator to create a bootable USB stick, I started my first adventure – figuring out how to get the IdeaPad to boot from USB. A bit of quick googling told me that the trick was to alternately tap F10 and F12 during the boot sequence. This brought up a boot menu that allowed me to select the USB stick.

Once Ubuntu had booted off of the USB stick, I opened up GParted and went about making some space for my new operating system. The process was straightforward – I selected the largest existing partition (it also helped that it was labelled WINDOWS_OS), and split it in half. My only mistake in this process was to choose to put the new partition in front of the existing partition on the drive. Because of this, GParted had to copy all of the data on the Windows partition to a new physical location on the hard drive, a process that took about three hours.

The final partitioning scheme with my new Linux partition highlighted

The final partitioning scheme with my new Linux partition highlighted

With my hard drive appropriately partitioned, it was time to install the operating system. The modern Ubuntu installer pretty much takes care of everything, even going so far as selecting an appropriate space to use on the hard drive. I simply told it to install alongside the existing Windows partition, and let it take care of the details.

The installer finished its business in short order, and I restarted the machine. Ubuntu booted with no issues, but my Windows 8 partition refused to cooperate. It would seem as though something that the installer did wasn’t getting along well with UEFI/SecureBoot. Upon attempting to boot Windows, I got the following message:

error: Secure Boot forbids loading module from (hd0,gpt8)/boot/grub/x86_64-efi/ntfs.mod.
error: failure reading sector 0x0 from ‘cd0’
error: no such device: 0030DA4030DA3C7A
error: can’t find command ‘drivemap’
error: invalid EFI file path

Press any key to continue…

Uh oh.

Like I said, I could boot Ubuntu, so I headed on over to their website and read their page on UEFI. At first glance, it seemed as though I had done everything correctly. The only place that I deviated from these instructions was in manually resizing my Windows partition to create space for my new Ubuntu partition.

Thinking that I might be experiencing troubles with  my boot partition, I took a shot at running Ubuntu’s Boot-Repair utility. It seemed to do something, but upon restarting the machine, I found that I had even more problems – now a Master Boot Record wasn’t found at all:

It would appear as though I may have made things worse...

It would appear as though I may have made things worse…

After dismissing the boot device error, I was prompted to choose which device to boot from. I chose to boot Windows’ UEFI Repair partition, and was (luckily) able to get to a desktop. Unfortunately, none of the other partitions on the device seem to work, so I’m back where I started at the beginning, except that now in addition to having to put up with Windows 8, I also have a broken master boot record.

Lenovo: 1 / Jon: 0.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.

Querying the State of a Hardware WiFi Switch with RF-Kill

October 8th, 2012 No comments

The laptop that I’m writing this post from has a really annoying strip of touch-response buttons above the keyboard that control things like volume and whether or not the wifi card is on. By touch-response, I mean that the buttons don’t require a finger press, but rather just a touch of the finger. As such, they provide no haptic feedback, so it’s hard to tell whether or not they work except by surveying the results of your efforts in the operating system.

The WiFi button in particular has go to be the worst of these buttons. On Windows, it glows a lovely blue colour when activated, and an angry red colour when disabled. This directly maps to whether or not my physical wireless network interface is enabled or disabled, and is a helpful indicator. Under Linux Mint 12 however, the “button” is always red, which makes it a less than helpful way to diagnose the occasional network drop.

Lately, I’ve been having trouble getting the wifi to reconnect after one of these drops. To troubleshoot, I would open up the Network Settings panel in Mint, which looks something like this:

Mint 12's Wireless Network Configuration Panel

The only problem with this window is that the ON/OFF slider that controls the state of the network interface would refuse to work. If I drag it to the ON position, it would just bounce back to OFF without changing the actual state of the card.

In the past, this behaviour has really frustrated me, driving me so far as to reboot the machine in Windows, re-activate the physical interface, and then switch back to Mint to continue doing whatever it was that I was doing in the first place. Tonight, I decided to investigate.

I started out with my old friend iwconfig:

jonf@jonf-mint ~ $ sudo iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.

wlan0     IEEE 802.11abgn  ESSID:off/any
Mode:Managed  Access Point: Not-Associated   Tx-Power=off
Retry  long limit:7   RTS thr:off   Fragment thr:off
Encryption key:off
Power Management:off

As you can see, the wireless interface is listed, but it appears to be powered off. I was able to confirm this by issuing the iwlist command, which is supposed to spit out a list of nearby wireless networks:

jonf@jonf-mint ~ $ sudo iwlist wlan0 scanning
wlan0     Interface doesn’t support scanning : Network is down

Again, you can see that the interface is not reacting as one might expect it to. Next, I attempted to enable the interface using the ifconfig command:

jonf@jonf-mint ~ $ sudo ifconfig wlan0 up
SIOCSIFFLAGS: Operation not possible due to RF-kill

Ah-ha! A clue! Apparently, something called rfkill was preventing the interface from coming online. It turns out that rfkill is a handy little tool that allows you to query the state of the hardware buttons (and other physical interfaces) on your machine. You can see a list of all of these interfaces by issuing the command rfkill list:

jonf@jonf-mint ~ $ rfkill list
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: yes
1: hp-wifi: Wireless LAN
Soft blocked: no
Hard blocked: yes

Interestingly enough, it looks like my wireless interface has been turned off by a hardware switch, which is what I had suspected all along. The next thing that I tried was the rfkill event command, which tails the list of hardware interface events. Using this tool, you can see the effect of pressing the physical switches and buttons on the chasis of your machine:

jonf@jonf-mint ~ $ rfkill event
1349740501.558614: idx 0 type 1 op 2 soft 0 hard 0
1349740505.153269: idx 0 type 1 op 2 soft 0 hard 1
1349740505.354608: idx 1 type 1 op 2 soft 0 hard 1
1349740511.030642: idx 1 type 1 op 2 soft 0 hard 0
1349740515.558615: idx 0 type 1 op 2 soft 0 hard 0

Each of the lines that the tool spits out shows a single event. In my case, it shows the button that controls the wireless interface switching the hard block setting (physical on/off) from 0 to 1 and back.

After watching this output while pressing the button a few times, I realized that the button does actually work, but that when the interface is turned on, it can take upwards of 5 seconds for the machine to notice it, connect to my home wireless, and get an ip address via DHCP. In the intervening time, I had typically become frustrated and pressed the button a few more times, trying to get it to do something. Instead, I now know that I have to press the button exactly once and then wait for it to take effect.

I stand by the fact that this is a piss-poor design, but hey, what do I know? I’m not a UX engineer for HP. At least it’s working again, and I am reconnected to my sweet sweet internet.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.

Python Development on Linux and Why You Should Too

September 1st, 2012 25 comments

If you’re a programmer and you use Linux but you haven’t yet entered the amazing world that is Python development, you’re really missing out on something special. For years, I dismissed Python as just another script kiddie language, eschewing it for more “serious” languages like Java and C#. What I was missing out on were the heady days of rapid development that I so enjoyed while hacking away on Visual Basic .NET in my early years of university.

There was a time when nary a day would go by without me slinging together some code into a crappy Windows Forms application that I wrote to play with a new idea or to automate an annoying task. By and large, these small projects ceased when I moved over to Linux, partially out of laziness, and partially because I missed the rapid prototyping environment that Visual Basic .NET provided. Let’s face it – Java and C# are great languages, but getting a basic forms app set up in either of them takes a significant amount of time and effort.

Enter Python, git/github, pip, and virtualenv. This basic tool chain has got me writing code in my spare time again, and the feeling is great. So without further ado, let me present (yet another) quick tutorial on how to set up a bad-ass Python development environment of your own:

Step 1: Python

If there’s one thing that I really love about Python, it’s the wide availability of libraries for most any task that one can imagine. An important part of the rapid prototyping frame of mind is to not get bogged down on writing low-level libraries. If you have to spend an hour or two writing a custom database interface layer, you’re going to lose the drive that got you started in on the project in the first place. Unless of course, the purpose of the project was to re-invent the database interface layer. In that case, all power to you. In my experience, this is never a problem with Python, as its magical import statement will unlock a world of possibilities that is occupied by literally thousands of libraries to do most anything that you can imagine.

Install this bad boy with the simple command sudo apt-get install python and then find yourself a good python tutorial with which to learn the basics. Alternatively, you can just start hacking away and use StackOverflow to fill in any of the gaps in your knowledge.

Step 2: Git/Github

In my professional life, I live and die by source control. It’s an excellent way to keep track of the status of your project, try out new features or ideas without jeopardizing the bits of your application that already work, and perhaps most importantly, it’s a life saver when you can’t figure out why in the hell you decided to do something that seemed like a good idea at the time but now seems like a truly retarded move. If you work with other developers, it’s also a great way to find out who to blame when the build is broken.

So why Git? Well, if time is on your side, go watch this 1 hour presentation by Linus Torvalds; I guarantee that if you know the first thing about source control, he will convince you to switch. If you don’t have that kind of time on your hands (and really, who does?) suffice it to say that Git plays really well with Github, and Github is like programming + social media + crack. Basically, it’s a website that stores your public (or private) repositories, showing off your code for all the world to see and fork and hack on top of. It also allows you to find and follow other interesting projects and libraries, and to receive updates when they make a change that you might be interested in.

Need a library to do fuzzy string matching? Search Git and find fuzzywuzzy. Install it into your working environment, and start playing with it. If it doesn’t do quite what you need, fork it, check out the source, and start hacking on it until it does! Github is an amazing way to expand your ability to rapid prototype and explore ideas that would take way too long to implement from scratch.

Get started by installing git with the command sudo apt-get install git-core. You should probably also skim through the git tutorial, as it will help you start off on the right foot.

Next, mosey on over to Github and sign up for an account. Seriously, it’s awesome, stop procrastinating and do it.

Step 3: Pip

I’ve already raved about the third-party libraries for Python, but what I haven’t told you yet is that there’s an insanely easy way to get those libraries into your working environment. Pip is like a repository just for Python libraries. If you’re already familiar with Linux, then you know what I’m talking about. Remember the earlier example of needing a fuzzy string matching library in your project? Well with pip, getting one is as easy as typing pip install fuzzywuzzy. This will install the fuzzywuzzy library on your system, and make it available to your application in one easy step.

But I’m getting ahead of myself here: You need to install pip before you can start using it. For that, you’ll need to run sudo apt-get install python-setuptools python-dev build-essential && sudo easy_install -U pip

The other cool thing about pip? When you’re ready to share your project with others (or just want to set up a development environment on another machine that has all of the necessary prerequisites to run it) you can run the command pip freeze > requirements.txt to create a file that describes all of the libraries that are necessary for your app to run correctly. In order to use that list, just run pip install -r requirements.txt on the target machine, and pip will automatically fetch all of your projects prerequisites. I swear, it’s fucking magical.

Step 4: Virtualenv

As I’ve already mentioned, one of my favourite things about Python is the availability of third-party libraries that enable your code to do just about anything with simple import statement. One of the problems with Python is that trying to keep all of the dependencies for all of your projects straight can be a real pain in the ass. Enter virtualenv.

This is an application that allows you to create virtual working environments, complete with their own Python versions and libraries. You can start a new project, use pip to install a whole bunch of libraries, then switch over to another project and work with a whole bunch of other libraries, all without different versions of the same library ever interfering with one another. This technique also keeps the pip requirements files that I mentioned above nice and clean so that each of your projects can state the exact dependency set that it needs to run without introducing cruft into your development environment.

Another tool that I’d like to introduce you to at this time is virtualenvwrapper. Just like the name says, it’s a wrapper for virtualenv that allows you to easily manage the many virtual environments that you will soon have floating around your machine.

Install both with the command pip install virtualenv virtualenvwrapper

Once the installation has completed, you’ll may need to modify your .bashrc profile to initialize virtualenvwrapper whenever you log into your user account. To do so, open up the .bashrc file in your home directory using your favourite text editor, or execute the following command: sudo nano ~/.bashrc 

Now paste the following chunk of code into the bottom of that file, save it, and exit:

# initialize virtualenv wrapper if present
if [ -f /usr/local/bin/ ] ; then
. /usr/local/bin/

Please note that this step didn’t seem to be necessary on Ubuntu 12.04, so it may only be essential for those running older versions of the operating system. I would suggest trying to use virtualenvwrapper with the instructions below before bothering to modify the .bashrc file.

Now you can make a new virtual environment with the command mkvirtualenv <project name>, and activate it with the command workon <project name>. When you create a new virtual environment, it’s like wiping your Python slate clean. Use pip to add some libraries to your virtual environment, write some code, and when you’re done, use the deactivate command to go back to your main system. Don’t forget to use pip freeze inside of your virtual environment to obtain a list of all of the packages that your application depends on.

Step 5: Starting a New Project

Ok, so how do we actually use all of the tools that I’ve raved about here? Follow the steps below to start your very own Python project:

  1. Decide on a name for your project. This is likely the hardest part. It probably shouldn’t have spaces in it, because Linux really doesn’t like spaces.
  2. Create a virtual environment for your project with the command mkvirtualenv <project name>
  3. Activate the virtual environment for your project with the command workon <project name>
  4. Sign into Github and click on the New Repository button in the lower right hand corner of the home page
  5. Give your new repository the same name as your project. If you were a creative and individual snowflake, the name won’t already be taken. If not, consider starting back at step 1, or just tacking your birth year onto the end of the bastard like we used to do with hotmail addresses back in the day.
  6. On the new repository page, make sure that you check the box that says Initialize this repository with a README and that you select Python from the Add .gitignore drop down box. The latter step will make sure that git ignores files types that need not be checked into your repository when you commit your code.
  7. Click theCreate Repository button
  8. Back on your local machine, Clone your repository with the command git clone<github user name>/<project name> this will create a directory for your project that you can do all of your work in.
  9. Write some amazing fucking code that blows everybody’s minds. If you need some libraries (and really, who doesn’t?) make sure to use the pip install <library name> command.
  10. Commit early, commit often with the git commit -am “your commit message goes here” command
  11. When you’re ready to make your work public, post it to github with the command git push<github user name>/<project name>
  12. Don’t forget to script out your project dependencies with the pip freeze > requirements.txt command
  13. Finally, when you’re finished working for the day, use the deactivate command to return to your normal working environment.

In Conclusion:

This post is way longer than I had originally intended. Suck it. I hope your eyes are sore. I also hope that by now, you’ve been convinced of how awesome a Python development environment can be. So get out there and write some amazing code. Oh, and don’t forget to check out my projects on github.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.
Categories: Jon F, Programming Tags: , ,

Batch Converting FLAC to MP3

April 2nd, 2012 1 comment

I came across this neat script somewhere on the internet while trying to batch convert a folder full of FLAC files to mp3 files. Hopefully it will help somebody else:

for file in *.flac; do flac -cd “$file” | lame -b 320 -h – “${file%.flac}.mp3”; done

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.
Categories: Jon F, Open Source Software Tags:

Wireless Networking: Using a Cisco/Linksys WUSB54GC on Gentoo

November 13th, 2011 1 comment

We live in an old house, which has the unfortunate side-effect of lacking a wired network of any kind. All of our machines connect to a wireless network, and my desktop is no exception. I’ve got an old WUSB54GC wireless stick that was manufactured some time in 2007. In computer years, this is way old hardware. But with a bit of work, I managed to get it working with my Gentoo install.

This bitch is old... but it works

I started out by installing the NetworkManager applet with a tutorial on the Gentoo Wiki. This was a straightforward process, and after a restart, the applet icon appeared in the top right corner of my screen. If you left-click on the icon, it drops down a menu that lists your wireless interfaces. Under the Wireless Networks heading, it said that it was missing the firmware necessary to talk to my hardware.

The next step was to look around the net and figure out the firmware/kernel module combination that supports this stick. I found my answer over at the SerialMonkey project, which is run by a group that took on maintenance of older Ralink firmware after the company of the same name dropped support. According to the SerialMonkey hardware guide, my stick (or at least a very similar stick called the WUSB54GR) works with the rt73usb kernel module and related firmware.

This known, there are two methods of proceeding. Those running older kernels may need to manually compile the necessary packages using instructions similar to these, from the Arch Linux project. For more modern kernels, the Gentoo project provides a Wiki entry detailing the necessary steps.

After following the steps in the Gentoo Wiki entry, I restarted my system, and now have full wireless support. Genius!

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
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Categories: Gentoo, Jon F Tags: , , , ,

Can you install Gnome3 on Gentoo?

November 13th, 2011 1 comment

So my base Gentoo installation came with Gnome 2.3, which while solid, lacks a lot of the prettiness of Gnome’s latest 3.2 release. I thought that I might like to enjoy some of that beauty, so I attempted to upgrade. Because Gnome 3.2 isn’t in the main portage tree yet, I found a tutorial that purported to walk me through the upgrade process using an overlay, which is kind of like a testing branch that you can merge into the main portage tree in order to get unsupported software.

Since the tutorial that I linked above is pretty self-explanatory, I won’t repeat the steps here. There’s also the little fact that the tutorial didn’t work worth a damn…

Problem 1: Masked Packages

#required by dev-libs/folks-9999, 
required by gnome-base/gnome-shell-3.2.1-r1, 
required by gnome-base/gdm-[gnome-shell], 
required by gnome-base/gnome-2.32.1-r1, 
required by @selected, 
required by @world (argument)
>=dev-libs/libgee- introspection
#required by gnome-extra/sushi-0.2.1, 
required by gnome-base/nautilus-3.2.1[previewer], 
required by app-cdr/brasero-3.2.0-r1[nautilus], 
required by media-sound/sound-juicer-2.99.0_pre20111001, 
required by gnome-base/gnome-2.32.1-r1, 
required by @selected, 
required by @world (argument)
>=media-libs/clutter-gtk-1.0.4 introspection

This one is pretty simple to fix: you can add the lines >=dev-libs/libgee- introspection and >=media-libs/clutter-gtk-1.0.4 introspection to the file /etc/portage/package.accept_keywords, or you can run emerge -avuDN world –autounmask-write to get around these autounmask behaviour issues

Problem 2: Permissions

--------------------------- ACCESS VIOLATION SUMMARY ---------------------------
LOG FILE "/var/log/sandbox/sandbox-3222.log"

FORMAT: F - Function called
FORMAT: S - Access Status
FORMAT: P - Path as passed to function
FORMAT: A - Absolute Path (not canonical)
FORMAT: R - Canonical Path
FORMAT: C - Command Line

F: mkdir
S: deny
P: /root/.local/share/webkit
A: /root/.local/share/webkit
R: /root/.local/share/webkit
C: ./epiphany --introspect-dump=

This one totally confused me. If I’m reading it correctly, the install script lacks the permissions necessary to write to the path /root.local/share/webkit/. The odd part of this is that the script is running as the root user, so this simple shouldn’t happen. I was able to give it the permissions that it needed by running chmod 777 /root/.local/share/webkit/, but I had to start the install process all over again, and it just failed with a similar error the first time that it attempted to write a file to that directory. What the fuck?

At 10pm at night, I couldn’t be bothered to find a fix for this… I used the tutorial’s instructions to roll back the changes, and I’ll try again later if I’m feeling motivated. In the mean time, if you know how to fix this process, I’d love to hear about it.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.
Categories: Gentoo, God Damnit Linux, Jon F Tags: , ,

Dropbox Meets Gentoo

November 6th, 2011 No comments

So I’m a big Dropbox user. I primarily use it to keep my personal info synchronized between my machines (don’t worry, I encrypt my stuff before dumping it into Dropbox, I’m not dumb), but it’s also handy for quickly sharing files with others.

Unfortunately, Dropbox doesn’t exist in the Gentoo portage tree.

To get started, head over to the Dropbox website and download the source tar.bzip file for your platform. Unzip it to your desktop, open a root terminal and cd into the resulting directory. Before you can actually install Dropbox, you’ll need to satisfy a few dependencies.

First, make sure that you’ve got python by typing emerge python into the aforementioned root terminal. Next, install docutils by typing emerge docutils in that same terminal. Now you should be able to install the dropbox stub by typing ./configure && make && make install.

At this point, Dropbox will have installed a stub of an application on your machine. You should be able to find it under Applications > Internet > Dropbox. When you launch this application, Dropbox will attempt to automatically download and install the binary portion of the application.

Optional: Verifying Binary Signatures

When dropbox downloads binary files, it verifies their legitimacy by calculating a digital signature and comparing it to a known value. In order for it to perform this task, you’ll need to have the pygpgme library installed on your system. Note that this is not the same as the python-gpgme library. They are different, and Dropbox requires the former. Like most Python libraries, pygpgme is a wrapper around a c-based library, in this case, GPGME. As such, the installation takes two steps. First, run emerge gpgme in your root terminal.

Second, you’ll need to install the pygpgme wrapper. It can be found on the project’s homepage at Launchpad. Unpack the tar.bzip, cd into the resulting directory, and run python build && python install from a root terminal. If the installation fails with an error message like

fatal error: gpgme.h: No such file or directory

then check the location of your gpgme.h file. It should have been included with the emerge gpgme command, but pygpgme expects it to live in /usr/include/. On my system, it was living in  /usr/include/gpgme/. I solved this problem by running cp /usr/include/gpgme/gpgme.h /user/include/. The only catch is that if you upgrade GPGME, you’ll need to remember that you copied the header file in order to make the python wrapper work. Once the file is copied, you should be able to run the setup script above.

Finally, run Dropbox and check to ensure that the warning message about binary signatures has gone away. You should now be good to go!


Edit: After I had figured all of this crap out, I realized that Dropbox actually is available in the Gentoo tree, but it’s called gnome-extra/nautilus-dropbox. You should be able to skip all of these steps and install Dropbox with the command emerge nautilus-dropbox, although I haven’t tried it myself.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
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Categories: Free Software, Gentoo, Jon F Tags: , ,


November 3rd, 2011 No comments

Tonight, I finally got X11 working on my Gentoo machine. For those who are following along, on Tuesday night I managed to get my machine up to a command line. The next logical step is a graphical window manager.

I’ve chosen to give Gnome3 a spin, but before I can dive into all of it’s shiny UI-goodness, I need an X11 server installed on my machine. Because I have an nVidia graphics card in my machine, and I’ve had great luck with Ubuntu’s proprietary nVidia drivers in the past, I decided to skip over the open-source Nouveau drivers this time around. I started out the installation by following Gentoo’s nVidia guide, supplementing with info pulled from the nVidia entry on the Gentoo Wiki.

Although X is supposed to configure your system automagically, it couldn’t find my screens or devices on my first run of startx. I looked about the internet for a bit, and found out that you can force X to automatically configure itself. Simply run Xorg -configure and copy the file that it creates into your Xorg config directory (you can find it in the log file, mine is at /usr/share/X11/xorg.conf.d/).

In my case, these automagical settings still needed a bit of tweaking. I noticed in the log file (again, mine is at /var/log/Xorg.0.log, your mileage may vary) that X was failing to load GLX, which is essentially for 3D acceleration. In my case, GLX was installed, but it NVIDIA’s version wasn’t being loaded. Once again, the Gentoo Wiki came through for me, instructing me to run eselect opengl set nvidia. This worked like a charm.

Finally, I had to install twm and xterm so that I could see X working. That was a quick and painless process. Now on to Gnome!

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
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Categories: Gentoo, Jon F, Xorg/X11 Tags:

Great Success!

November 1st, 2011 No comments

Just a quick note tonight – I finally managed to get a bootable Gentoo system installed!

After my last post, things were looking pretty grim. Instead of continuing to perpetuate the recompile/reboot cycle, I decided to start fresh, in hopes that I had simply missed a step the first time around. With this in mind, I started back at page one of the Gentoo Handbook and worked my way through the entire thing.

When it came time to compile my kernel, I opted for a slightly less error-prone method, and started off by installing Genkernel, a tool that automates some of the kernel creation steps. When running it however, I was sure to pass the –menuconfig parameter, which gave me full control over what modules were included in the final product.

Next, I followed the kernel tutorials in the Gentoo Handbook and on the Gentoo Wiki Asus P5Q-E page. This ensured that I included every component that was necessary for my system.

Once I rebooted the machine, a login prompt came up the first time. Great success indeed!

One little gotcha that’s important to note at this step. On my first login, I didn’t have any network access. Two things that might help:

  1. Open up /etc/conf.d/net in nano and add a line like config_eth0=”dhcp” for each network interface in your machine, where eth0 is the name of the interface. This tells the machine to use DHCP when initializing the device. On most home networks, this will get you an IP address.
  2. Make sure that any required modules are loaded. I have two network interfaces. One uses the sky2 module, and the other uses skge. You can check to ensure that these are loaded with the command lsmod | grep sky2 where sky2 is the name of the module that you’re looking for. If it isn’t loaded, run modprobe sky2 to get it up and running. Note that you may need to recompile your kernel with support for the module in question if you missed it first time ’round.

Tomorrow, I’ll compile an X11 server, and hopefully get started on the GNOME desktop environment. Christ there’s still a lot to do…

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
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Categories: Gentoo, Jon F, kernel, Networking Tags:

Kernel Panic!

November 1st, 2011 2 comments

So like Tyler, I’ve decided to run Gentoo. Hey, it seemed like a good idea at the time.

My experience thus far can be summed up with a single word: frustrating. I spent my first day working through the (excellent) Gentoo Handbook. Like Jake, I found it handy to have run lshw on my system prior to installing Gentoo. This provided me with a list of my hardware that I could refer back to during the installation process, and saved me a few headaches.

At first, my live-cd environment lacked a network connection. My machine has two network interfaces in it. One uses the sky2 kernel module, while the other uses skge. I ran:

modprobe skge
net-setup eth1
[follow on-screen instructions]

and was successful.

On that first day of dicking about, I managed to get all the way to Chapter 10: Configuring the Bootloader. It was at this point, in subchapter 10.d, that I was instructed to reboot the system, as though it would be a relaxing, daisy-scented walk in the park. Not so.

Apparently, the kernel that I’ve managed to compile does not recognize the SATA interface on my motherboard. When I attempt to boot, GRUB hands control off to the kernel, which goes looking for my root partition on /dev/sda3. It then dies with a message like

Kernel panic – not syncing: VFS: Unable to mount root fs on unknown-block(8,3)

This error message is the bane of my existence.

After a great deal of head-vs-desk action, approximately 37 kernel compilations, and a great deal of googling, I managed to find a Gentoo wiki entry that instructs users of my chipset on how to compile their very own working kernel. Tonight, I intend to follow it, in hopes that I can get the system to boot some time soon.

At this rate, I’ll be lucky to have a working desktop by the end of the experiment.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
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Categories: Gentoo, God Damnit Linux, Jon F, Linux Tags:

Richard M. Stallman: Troll

October 10th, 2011 15 comments

If you’ve been living under a rock for the past week, you may not be aware that Steve Jobs, co-founder and legendary CEO of Apple Inc., has recently died after a long and protracted battle with pancreatic cancer. After the announcement of his death, many news outlets (tech-oriented and otherwise) ran lengthy tributes to a man who has forever (and often disruptively) altered more industries than any other in recent memory.

The day after Jobs’ death, Free Software visionary and GNU Project founder Richard M. Stallman had this to say about the man:

Steve Jobs, the pioneer of the computer as a jail made cool, designed to sever fools from their freedom, has died.

As Chicago Mayor Harold Washington said of the corrupt former Mayor Daley, “I’m not glad he’s dead, but I’m glad he’s gone.” Nobody deserves to have to die – not Jobs, not Mr. Bill, not even people guilty of bigger evils than theirs. But we all deserve the end of Jobs’ malign influence on people’s computing.

Unfortunately, that influence continues despite his absence. We can only hope his successors, as they attempt to carry on his legacy, will be less effective.

Upon finding this post via Twitter, my immediate reaction was a deep loss of respect for Stallman, a man whose contributions to the Free Software movement cannot be understated. The way that I see it, Stallman and Jobs are one in the same. Both are (or were, in the case of the latter) visionaries, both contributed immeasurably to an industry that employs, informs, and entertains me on a daily basis, and both are/were zealots when it came to their personal opinions about software.

Now I’m not an Apple guy. Far from it, in fact. I don’t own a single Apple product, I use Linux whenever and wherever possible, and I only break from the four essential freedoms when obtaining and enjoying media that cannot be accessed otherwise. But regardless of your thoughts on Steve Jobs, the man deserves your respect.

While Stallman qualified his statement by noting that nobody deserves to die, he also focused his personal fanaticism when it comes to the perceived threat of non-free software directly on the shoulders of one man in a world of many.

There’s something about Freedom that Stallman doesn’t seem to (or want to, as all accounts paint him as a pretty smart dude) understand. It’s a simple point, and one that needs to be reiterated often: Freedom is the right to choose. In politics, in products, and in computing, freedom is the right to choose what is best for you.

Steve Jobs put his ideas and his products into the free market, and paying customers often chose them above those of Stallman. Perhaps those customers got shafted, but when faced with a choice between the freedom to edit configuration files and the beautiful design of an Apple product, they unsurprisingly chose the latter.

That’s freedom, whether you like it or not. Fuck Richard Stallman.

Further Reading:

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
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Ubuntu 11.04 Installer Fail

August 24th, 2011 3 comments

So I decided to take a go at Ubuntu 11.04 in a virtual machine before taking the leap and installing it for real. As I understand it, the new Unity desktop is a pretty major departure from the Gnome 2.x desktop that I’m used to, and I want to see if it’s as bad as it looks in the screenshots.

Unfortunately, I’ve yet to make it to the desktop, as Ubuntu has decided that it will take 42 minutes to download some language packs that I neither want or need.

Didn’t I tell it what language I speak as the first step of the install process? Surely this can be done later.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
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Categories: God Damnit Linux, Jon F, Ubuntu Tags:

Linux Multimedia Studio on Ubuntu 10.04

July 31st, 2011 1 comment

Recently, Tyler linked me to Linux Multimedia Studio, a Fruityloops-type application for Linux. Since I’m big into music recording and production, he figured that I’d be interested in trying it out, and he was right. Unfortunately, the developers of same were not as interested.

To start off, I installed the application from a PPA with the following terminal commands:

sudo apt-add-repository ppa:dns/sound
sudo aptitude update
sudo aptitude install lmms

After the install process finished, I tried to launch the application from the command line, only to see a bunch of nasty error messages:

jonf@THE-LINUX-EXPERIMENT:~$ sudo lmms
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
Segmentation fault

I dumped the errors into Google, and found a helpful thread on the Ubuntu forums that suggested that I uninstall Bluetooth Audio Services from my machine. Since I don’t use bluetooth audio in any capacity, I happily obliged. When finished, my list of installed items with Bluetooth in the name looked like this:

A list of installed software matching the search term "bluetooth" in Ubuntu Software Centre

Unfortunately, I didn't think ahead enough to note down the names of the packages that I uninstalled.

After ridding myself of Bluetooth audio support, I tried to launch the application again. Unfortunately, I got another Segmentation fault error:

jonf@THE-LINUX-EXPERIMENT:~$ sudo lmms
Segmentation fault

Reading on in the thread, I saw somebody suggest that I check the dmesg tail for messages pertaining to the crash:

jonf@THE-LINUX-EXPERIMENT:~$ dmesg | tail
[  233.302221] JFS: nTxBlock = 8192, nTxLock = 65536
[  233.314247] NTFS driver 2.1.29 [Flags: R/O MODULE].
[  233.343361] QNX4 filesystem 0.2.3 registered.
[  233.367738] Btrfs loaded
[ 2233.118020] __ratelimit: 33 callbacks suppressed
[ 2233.118026] lmms[10706]: segfault at 7f241c7fdd80 ip 00007f241c7fdd80 sp 00007f24187f8a38 error 14 in[7f241ca01000+1000]
[ 2523.015245] lmms[10808]: segfault at 7fd80e9bcd80 ip 00007fd80e9bcd80 sp 00007fd80a9b7a38 error 14 in[7fd80ebc0000+1000]
[ 2671.323363] lmms[10845]: segfault at 7fbe39a77d80 ip 00007fbe39a77d80 sp 00007fbe35a72a38 error 14 in[7fbe39c7b000+1000]
[ 2836.885480] lmms[11246]: segfault at 7f885b71ed80 ip 00007f885b71ed80 sp 00007f8857719a38 error 14 in[7f885b922000+1000]
[ 3039.773287] lmms[11413]: segfault at 7ff83056ed80 ip 00007ff83056ed80 sp 00007ff82c569a38 error 14 in[7ff830772000+1000]

On the last few lines, you can see that the error was thrown in a module called A bit of Googling turned up the fact that this module is a part of the LADSPA (Linux Audio Developers Simple Plugin API) stack, which provides developers with a standard, cross-platform API for dealing with audio filters and effects.

Scrolling down in the aforementioned thread, I found a post that suggested that I kill all PulseAudio activities on my system before attempting to run the application. PulseAudio is another part of the Linux audio layer that allows user-land applications to talk to your sound hardware via a simple API. It also provides some effects plugins and mixdown capabilities. I went ahead and killed the PulseAudio server on my machine with the following command:

jonf@THE-LINUX-EXPERIMENT:~$ killall pulseaudio

After executing this command, I still got a Segmentation fault when starting LMMS under my user account, but did actually get to a Settings panel when running it with Sudo:

jonf@THE-LINUX-EXPERIMENT:~$ sudo lmms
Home directory /home/jfritz not ours.
ALSA lib pcm_dmix.c:1010:(snd_pcm_dmix_open) unable to open slave
Playback open error: Device or resource busy
Expression 'snd_pcm_hw_params_set_buffer_size_near( self->pcm, hwParams, &bufSz )' failed in 'src/hostapi/alsa/pa_linux_alsa.c', line: 1331
Expression 'PaAlsaStreamComponent_FinishConfigure( &self->playback, hwParamsPlayback, outParams, self->primeBuffers, realSr, outputLatency )' failed in 'src/hostapi/alsa/pa_linux_alsa.c', line: 1889
Expression 'PaAlsaStream_Configure( stream, inputParameters, outputParameters, sampleRate, framesPerBuffer, &inputLatency, &outputLatency, &hostBufferSizeMode )' failed in 'src/hostapi/alsa/pa_linux_alsa.c', line: 1994
Couldn't open PortAudio: Unanticipated host error
Home directory /home/jfritz not ours.
Home directory /home/jfritz not ours.

Although the output appeared to be riddled with audio layer errors, and the Audio Settings tab of the Setup panel gave me a clue as to why:

Notice how the Audio Interface setting in that image says “Pulse Audio (bad latency!)”. I would hazard a guess that the latency issues with PulseAudio have something to do with the fact that I killed it just prior to getting this damned thing to launch. When I hit the OK button, I was able to see the application, but there was no sound.

Figuring that sound was a necessary component of an audio production application, I booted back to the Setup menu, and told the app to funnel its audio through JACK instead of PulseAudio. The JACK Audio Connection Kit is another sound subsystem, kind of like PulseAudio, that provides an API that developers can use to interface with a machine’s audio hardware. Because of its low latency performance, JACK is often considered to be the standard API for high-quality audio recording and production apps. Unfortunately, it doesn’t work worth a damn in LMMS:

jonf@THE-LINUX-EXPERIMENT:~$ sudo lmms
jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn and others.
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details

no message buffer overruns
JACK compiled with System V SHM support.
loading driver ..
SSE2 detected
creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
control device hw:0
SSE2 detected
all 32 bit float mono audio port buffers in use!
cannot assign buffer for port
cannot deliver port registration request
no more JACK-ports available!
No audio-driver working - falling back to dummy-audio-driver
You can render your songs and listen to the output files...
Home directory /home/jfritz not ours.
Home directory /home/jfritz not ours.
the playback device "hw:0" is already in use. Please stop the application using it and run JACK again
cannot load driver module alsa
Home directory /home/jfritz not ours.

Having dealt with JACK on a previous install, I had one more trick up my sleeve in my effort to get this bastard application to make a sound. I installed the JACK Control Panel from the Ubuntu Software Centre. It’s a QT app that interfaces with the JACK server and allows you to modify settings and stuff.

With it installed, I pressed the big green (or is it red – I’m colour blind, and hate when developers use these two colours for important status messages) Start button, only to encounter some nasty errors:

That might be a problem. I hit the messages button and found a message advising me to make a change to the /etc/security/limits.conf file so that JACK would be allowed to use realtime scheduling:

JACK is running in realtime mode, but you are not allowed to use realtime scheduling.
Please check your /etc/security/limits.conf for the following lines
and correct/add them:
@audio - rtprio 100
@audio - nice -10
After applying these changes, please re-login in order for them to take effect.
You don't appear to have a sane system configuration. It is very likely that you
encounter xruns. Please apply all the above mentioned changes and start jack again!

I figured that it was worth a shot, considering how far I’ve already gone just to try out a piece of software that I don’t really even need. I made the requested changes in the config file, restarted my machine and tried again… only to be greeted by the same damned error message.

At this point, I decided to give up on LMMS. It’s too damned complicated, and ultimately not worth my time. Perhaps when they release a version that I can install and start using without an hour of troubleshooting, I’ll come back and give it another shot. In the mean time, if you’re looking for a decent drum machine with more than a few tricks up its sleeve, check out Hydrogen Drum Machine. It works very well, and I’ve created some neat stuff in it.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
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Recovering a Corrupted Banshee Database

February 27th, 2011 11 comments

A couple of nights ago, I left Banshee running overnight, filling my phone with music to listen to the next day at work. Sometime during that process, the media player crashed in a big way, and my entire system ground to a halt. When I woke up the next morning, my computer was frozen solid, with no keyboard or mouse input accepted, and the system clock hadn’t advanced since 11:16pm the previous night. I did a hard reboot, hoping that all would be well when it came back up.

Boy was I wrong.

The Problem

It seems that when Banshee went down, it took my library database file with it. Now, whenever I launch the application, I get a lovely dialog box that looks something like this:

Launching the application from the command line provides more details:

jonf@THE-LINUX-EXPERIMENT: ~/.config/banshee-1$ banshee-1
[Info  11:20:32.175] Running Banshee 1.9.0: [source-tarball (linux-gnu, x86_64) @ 2010-12-09 13:07:07 EST]
[Warn  11:20:32.451] Service `Banshee.Database.BansheeDbConnection’ not started: The database disk image is malformed
database disk image is malformed
[Warn  11:20:32.453] Caught an exception – Mono.Data.Sqlite.SqliteException: The database disk image is malformed

Apparently, the SQLite database that forms the backend of Banshee is severely corrupted, and the application can’t open it for reading. Based on the command line output, I figured that Banshee uses SQLite3 for its database, and after a little bit of research, I found out that it stores the database file at ~/.config/banshee-1/banshee.db. After installing the SQLite3 package from my repositories with the command sudo apt-get install sqlite3, I was able to connect to the database without issue. A little bit of reading over at showed me how to do an integrity check on the database, which came back with some nasty results:

jonf@THE-LINUX-EXPERIMENT:~/.config/banshee-1$ sqlite3 -interactive banshee.db
SQLite version 3.6.22
Enter “.help” for instructions
Enter SQL statements terminated with a “;”
sqlite> PRAGMA integrity_check;
*** in database main ***
Main freelist: 2291 of 2292 pages missing from overflow list starting at 18928
On tree page 28 cell 4: Child page depth differs
On tree page 28 cell 6: 2nd reference to page 15475
On tree page 28 cell 6: Child page depth differs

On tree page 16807 cell 25: Child page depth differs
On tree page 16807 cell 26: 2nd reference to page 18171
On tree page 16807 cell 26: Child page depth differs

Each line of this output refers to a broken or corrupted index, with a total of 99 errors reported. Yikes.

The Solution

Before attempting to fix the problem, I made a backup of the broken database, just in case some data could be resurrected from it. To do this, I made sure that Banshee wasn’t running, and then made a copy of the database file with the command cp ~/.config/banshee-1/banshee.db ~/.config/banshee-1/banshee.db.old.

Since the integrity check showed a number of broken or corrupted indices, I thought perhaps I would be able to recover the database by rebuilding all of its indices. A quick scan of the SQLite documentation turned up the REINDEX function. Again, I connected to the database through the command-line interpreter, and gave it a shot:

jonf@THE-LINUX-EXPERIMENT:~/.config/banshee-1$ sqlite3 -interactive banshee.db
SQLite version 3.6.22
Enter “.help” for instructions
Enter SQL statements terminated with a “;”
sqlite> REINDEX;
Error: database disk image is malformed

That clearly didn’t work.

My next thought was to drop and re-create all of the indices in the database, in hopes that I could rebuild them. I used the graphical tool sqliteman (available from your repositories with the command sudo apt-get install sqliteman) to dump the database schema out to a text file and then scrolled through the file looking for each index. I managed to drop all but four of them, but got the image malformed error whenever I tried to drop the remaining four or recreate any of the ones that were successfully dropped.

Out of ideas, I resorted to attempting to recover what data I could from the mangled file. Using sqliteman, I created a dump of my library data to go along with the schema dump that I had created earlier. The good thing about this dump is that it contains all of the data with none of the indices. Next, I opened up a terminal and navigated to the temporary directory where I had saved the database dump. Using the sqlite3 command line interpreter, I built an image of the old database from the dump:

jonf@THE-LINUX-EXPERIMENT:~/Desktop/banshee$ sqlite3 -interactive banshee.db
SQLite version 3.6.22
Enter “.help” for instructions
Enter SQL statements terminated with a “;”
sqlite> .read dump.sql

Finally, I copied the newly created database into the banshee data directory with the command cp ~/Desktop/banshee/banshee.db  ~/.config/banshee-1/banshee.db.

The next time I started the application, all of my data was restored.


I’ve put a lot of work into collecting and maintaining all of the music in my Banshee library. In order to avoid losing all of that work, I’ve decided to write a short script that takes a backup image of the library database every so often, and puts it in a safe place on my hard drive. Once I get that put together, I’ll throw it up on here for so that everybody can use it.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.

Well, Here Goes Nothing

December 14th, 2010 No comments

During a routine update of my Fedora 13 system, I received the following notification:

You’ll notice, upon careful inspection, that the update utility would like to remove my kernel. This ought to be fun.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.
Categories: God Damnit Linux, Jon F Tags:

Why I Hate Samba

December 12th, 2010 9 comments

This file copy is running over my local wireless network:

Apparently Samba uses less than 1% of available network bandwidth for file copies...

That is all.

On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.
Categories: God Damnit Linux, Jon F Tags: , ,