Tag Archives: software

Oops, That Kernel Didn’t Work!

Being security conscious, I try to keep everything up to date. This includes the Linux kernel that is the heart of our systems.

In keeping with that, a few weeks ago I changed all of my Mint 17.3 machines to the kernel recommended in the kernel chooser.

Kernel chooser

Kernel chooser

As you can see above, I’m running the kernel recommended by Linux Mint. This went well for all but one of my machines. My bedside, 4 processor, 8 gigs of RAM machine seemed to run fine for a week or so, but I found that when running certain software packages; the computer would completely freeze. Anything to do with video or graphics would freeze at random times with no warning.

Scouring the logs was pointless, as the freeze happened before anything was logged.

At first I blamed a new wireless keyboard / mouse combo that was purchased at the same time. Putting a USB set back in, proved the wireless was not the cause.

Searching the Mint and other forums showed that many people were having the same problem I was. A combination of the processor type and graphics card seemd to be to blame.

By this time I had already removed the previous kernel, so it was time to put it back!

Open your Update Manager, click on View, and then select Linux kernels

In my case, I re-installed the 3.13 kernel that had been working flawlessly before. Of course if there are notes about security issues or regressions that could impact your system, then chose another.

Installing a different kernel

Installing a different kernel

Next you need to edit the GRUB config file, as I was booting quietly, not displaying the boot menu. To do that, simply drop to a terminal and edit it with your favorite text editor. I use medit

$ sudo medit /etc/default/grub

will open your text editor in super user mode.

Edit grub

Edit grub

Editing Grub

Editing Grub

You’ll see in the above example, I’ve commented out, using the # symbol, to have the boot process ignore the two commands at lines 7 and 8. Doing this, will now let me see the grub boot menu at startup. Save and close the file, and then, it’s very important that you tell grub that you’ve changed it. Do this by issuing the command:

$ sudo update-grub

Now it’s time to reboot. When you do, at the grub boot window, arrow down to Select previous Linux version, and select that.

Once you’ve booted up, and after you are satisfied that there are no issues with the new kernel, you can then go back into the update manager and un-install the previous kernel that was giving you fits.

Note: After much experimenting, I was able to upgrade to kernel 3.16, and maintain a stable machine!

 

New Project: Building A Kodi Media Server

January has been busy with many projects on the farm. Our Linux related project was the building of a Kodi *(Formally XBMC) media server.

Kodi Logo

Kodi Logo

We have hundreds of goat and other home movies, as well as an extensive library of our favorite films. The vast majority of our media have been stored for years on DVD, often stuck into one of our stack of Sony 400 DVD disk changers for easy viewing. Well the disk changers are getting old, 2 of them have stopped working all together, so why not play our media from hard disk instead!

There is always an old computer or two laying around the farm, doing nothing, but we decided it would be fun to build our Kodi box out of a Raspberry Pi computer instead!

We got our Pi from Amazon, in a kit that included the case, power supply, WiFi adapter, and a heat sink for the processor. For media storage, we purchased an external 5tb hard drive, which at the compression level we’re using, should hold over 1000 full length movies, plus my extensive collection of old time radio shows I’ve been collecting for over 50 years.

A trip to the Kodi.tv download page let us select the disk image required for our Raspberry Pi.

Once our disk image was downloaded, we used the Disks utility in the Linux Mint Control Center to select and then burn the disk image to a 16gb Class 10 micro SD card. Entire process took about 10 minutes.

Writing the disk image

Writing the disk image

Once burned, insert the micro SD card into your Raspberry Pi, and boot it up. Our bedroom TV will be getting the file server, so the Pi is plugged into our 32 inch LED TV with an HDMI cable.

Once booted, you can go into the various setup screens to make your new file server look and behave just how you’d like it to.

Movie demo screen from Kodi.tv

Movie demo screen from Kodi.tv

I’d recommend plugging a USB keyboard and mouse into your Raspberry Pi to make things easier when doing setup, like connecting to your home WiFi network.

What kind of media is entirely up to you. If your local laws allow fair use of your commercial DVD’s and music, then put them on your Kodi, and enjoy them easier than ever before!  Spending so much time in bed as I do, because of my Multiple Sclerosis, it’s sure nice to find a favorite film without digging through stacks of disks!

Kore Android Applicaiton

Kore Android Applicaiton

The next thing you want to do is install the free Kore, Kodi application for your phone or tablet. Kore gives you complete control of your Kodi server, and allows you to browse the content of your server in real time, as well as do maintenance duties like updating your media lists and descriptions.

Additionally, there are tons of open source additions to your Kodi that you can download directly from your Kodi server. Setting our home screen up with time and weather was the first thing we did. Adding Youtube and other favorite video sources to your Kodi just takes a few clicks.

Add ons are so easy to build, that I’ve already got one put together for our GoatsLive web site. Looking forward to submitting it for inclusion in the official repository!

After 3 weeks of use, my only complaint about this system, is why I didn’t do it much sooner!

Important Facts About Kodi

The Kodi team are open source developers. Kodi does NOT sell hardware,  they just make their wonderful software available to anyone who wants to use it.

The Kodi name and logo are trademarked by the Kodi team, and may not be used by sellers of hardware. Please do not be suckered in to purchasing a  “Free Internet TV” type of box that are sold online via ebay and youtube. These sources, with very few exceptions, are promoting and selling devices that are designed for piracy, using the good name of Kodi to do it. Most of these devices are selling in the $300 price range, but you can build a proper, legal Kodi box for as little as $35!

If you see someone selling Kodi branded hardware, please let the fine folks at Kodi know by using THIS LINK

Sometimes The Solution Is Right In Front Of You!

Printing a PDF file. Who knew it could be such a pain!

A few times over the last couple of years, I’ve needed to print a shipping label with a UPS or Fedex bar code on it.

My normal routine would be to open the label that was sent me, usually from Amazon.com or other online retailer, using the document viewer that’s built in to LInux Mint.

 

Document Viewer

Document Viewer

Every time I tried to print from the Document Viewer, using my Canon laser printer, it would print out a huge blob of black where the bar code should be.

I tried many times over the last couple of years to figure out why this was happening. The document always looked fine in the print preview screen, but would print out, a mess! I tried tons of settings on the printer, in Linux and everywhere else I could think of, with no luck.

Then yesterday, needing to print an Amazon return label, I drug the .pdf file into my Firefox web browser. Of course Firefox is able to open these and many other file formats. Holding my breath, I pushed print, and then headed in to my wife’s office where the networked printer lives. Viola! The label printed perfectly.

Moral, why did I try so hard to fix Document Viewer, when Firefox would print it out just fine!

 

Terminal Tools: Midnight Commander File Manager

As I’ve always said, I prefer to do things from the terminal when I can. When taking care of my many computers, it’s handy to have a file manager that will work over an SSH connection. Enter Midnight Commander.

Midnight Commander is a text based file manager, that is very powerful and simple to use.  I’d found it a few months ago, when I was trying to easily find some media files on my son’s computer, without him knowing I was poking around. This of course meant I couldn’t use VNC.

To install Midnight Commander, simply open a terminal and type the following:

sudo apt-get install mc

Of course, if you have connected to a remote computer, you can do the install on that remote machine with the same command.

Once installed, running Midnight Commander is as simple as opening a terminal, either locally or remotely and typing: mc

Midnight Commander

Midnight Commander

Midnight Commander includes an internal editor with syntax highlighting and an internal viewer with support for binary files!

 

Security: Watch What Your Kids Do Online!

If you have kids at home using the web, it’s important that you know what they are doing! One of the easiest ways to do that is to actually look at their screen.

Youngsters really should not be using the net in their own room, but rather in a central location in the house so you can keep an eye on them. But if they are using a laptop or desktop in their own room, it’s important to keep an eye on what they do. While my remaining child at home is 28, he is also profoundly autistic, functioning on the lever of a 4 year old. Here’s how I keep track of his net usage:

First, I use VNC. He is using a Dell laptop running Linux Mint 17. Running on Mint of course is the VNC server called vino-server.

Looking at the following screen grab, you can see the desktop sharing dialogue.

Vino setup

Vino setup

In the final section of the setup screen, you want to change the selection from where you see it, to Never. This will prevent the computer running the vino server from alerting the user that it is being connected to.

As you already know I’m sure, this lets me peek in and see what he’s looking at, and if it’s something he should not be looking at, I can block the site in my router.

VNC image

VNC image

In the example above, he was watching a Little Mermaid cartoon on Youtube while drawing one of his cartoons. *(He loves drawing cartoon characters sitting on the potty, I don’t know why!)

Other things you should do to protect your youngster include:

  • Using Opendns.org for their wonderful parental controls. They do a good job at blocking all the porn out there.
  • Use your routers built in filtering system. Block by keyword or specific URL to prevent your offspring from accessing them. *(keep in mind that if the site has a security certificate, then this can be bypassed by a clever kid, hence looking in on them from time to time!
  • Watch your router logs. My router logs tell me every site that has been visited for the last hour. It can be tedious, but checking the logs for sites you don’t want your kids going to.
  • Talk to your kids! Let them know what your expectations are where their network use concerned.