LinuxCON Kids’ day


Part of this year’s LinuxCON / ContainerCON in Toronto was a full day program called Kids’ Day. Its purpose was to foster an interest in technology among junior nerds and the children of their nerd parents (raises hand). My 12 and 15 year olds were keen to lay hands on some hardware and hang out with like-minded instructors, so we signed up.

What we did not know at the time was that the program was organized by Kids on Computers (@kidsoncomputers,, a charity dedicated toward bringing technology to communities where it doesn’t exist and where there is no internet access. Much of the first part of the session involved having the kids wipe Windows from a bunch of donated laptops and install GNU/Linux on them before they were to be shipped to Mexico as part of this endeavor. By my count, 17 kids were given flash drives with Ubermix ( and were walked through the steps to boot off of the flash drive, select the script that did the nuking and paving. I imagined I could smell the uranium and asphalt on the ground.

Having cleansed and consecrated the hardware, the children were instructed to connect to a local network containing an Intel NUC specially designed to act as an offline Wikipedia / Khan Academy / Open Street Maps / <So much more> server. Once that was done, it was a simple matter to enter “school” into the laptop’s Firefox browser to pull up the school interface and to see what was there. A complete listing of the services offered can be found on the site ( but I understand the NUC cost a little under $300 and runs CentOS.

As the laptops were connected to an ad-hoc network, they were able to ping and SSH to one another on the local network. The kids were shown how to do that and how to use SCP to move a greeting to other laptops with minimal/no security. When asked what I thought his greeting should say, I suggested ‘sudo apt install malware,’ which elicited a few chuckles. My sons had a grand time shutting each other’s systems down before I reminded them that they could change their administrator passwords or turn on the firewall. Thankfully, the instructors decided to move us along before things devolved into a mini black-hat conference.

The rest of the morning had the group playing with Scratch. For those of us old enough to remember, Scratch might remind you of the Logo language from a generation ago. But instead of moving a turtle around to create different shapes, you move a cat around and… create different shapes. The times, they are a changing.

The afternoon focused almost exclusively on the Arduino ( Kids connected Arduino Unos to their former windows laptops and used the installed Arduino IDE to upload programs they created or modified to make lights blink faster or slower, make speakers play tunes and respond to button presses.

All in all, Kids’ Day was extremely productive – for the kids, certainly, but for the community, for the other kids to be served by their efforts and for the amazing instructors who put it all together.

How to Verify the Integrity of a File with SHA-1

(Matt’s addendum to Eric’s video) There are other Secure Hash Algorithms available, however for the demonstration in this video, Eric will be using SHA-1.

Raspbian for example, offers what you need to verify your download using SHA-1. While it’s depreciated when compared to other Secure Hash Algorithm options, it does provide you with an idea how to verify the media you’ve downloaded before installing it.


Plex Media Server on the Raspberry Pi 2 – Joy and Anguish

Over the years, I have been collecting DVDs, backing up the movies to a desktop computer for playback on its big screen. Recently, projects like Kodi and Plex media server came along and promised to not only offer those same movies in a pleasing GUI, but to gather metadata about the movies and to save my place when I access them from different places. I would love to have a dedicated server so I don’t need to continuously run my desktop computer, but I’m too cheap to spring for a dedicated NAS. The Raspberry PI 2 promises an easy way to accomplish this goal without first having to earn a degree in computer science.

(Video syncs out with the audio at the end, but it’s all there otherwise)

Spirited googling took me to a rather detailed walkthrough by Richard Smith on YouTube. I used ‘dd’ in Ubuntu 15.10 on my laptop to create the Debian Wheezy microSD card. Then, I used wget to pull down the latest Plex Media Server package and used dpkg -i to build and install it. Then, I installed a few extra packages (mkvtoolnix, libexpat1 and ffmpeg). Then I restarted the server.

sudo service plexmediaserver restart

Lastly, I launched the gui (using ‘startx’), launched the default iceweasel browser and pointed it to the newly-launched plex server (http://localhost:32400/web/index.html). This brings the user to the standard Plex interface, where you can connect your server to your Plex account, if you have one. This makes the server visible to Plex clients using the same account (assuming port forwarding and firewalls are configured correctly).

Performance was surprisingly good. Movies launch after a short delay, the video and audio quality are excellent and there is no stuttering or lag. Streaming video from subscribed channels in Plex, such as Vimeo, seem to play just fine. Playback works well on the Chrome web app in Linux and on the Nexus 7 2014. The Plex clients for iOS refuse to connect, stating that the server needs to upgrade to the latest version. I got the same error on the iPhone, iPad and Apple TV 2.

Another disappointment is that the Pi2 is unable to transcode video. This makes it unable to play other videos I have accumulated over the years. For example, I have a number of .mp4 videos of television recordings I made for myself using EyeTV that just won’t play.

Notwithstanding these small shortcomings, the Raspberry Pi 2 does an admirable job playing video server, especially with hardware whose cost is scarcely more than a tank of gas.



Richard Smith’s YouTube guide to running the Plex Media Server on the Raspberry Pi 2:

Powered USB Hub: Belkin F5U404-BLK

Hard drive: Western Digital My Passport P/N: WD8Y8L0020BBL-01

Raspberry Pi 2 + kit on Amazon:

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Raspberry Pi 2 –