Saturday, 22 November 2014

Wheezy & Jessie, more than just a Toy Story.

I've just updated Raspbian on a RaspberryPi....it took hours!


But this wasn't just a routine apt-get update & upgrade, it was a move from Debian Wheezy to Jessie.


So all of my applications where updated, in addition to the operating system and many configuration files.

My RaspberryPi runs on Raspbian, which is based upon the Linux Debian distribution compiled for armhf.

Some background to Debian


Debian is a Linux operating system distribution devised by Ian Murdock about 20 years ago. The name is simply derived from his, and a former girl-friends name: Debra + Ian = Debian.

Each release has a project name based upon a Toy Story character (e.g. Buzz, Woody, Etch & so on).

There are 3 active versions or releases at any point in time:-
The Stable release; this is currently Wheezy
The Testing version; this is currently Jessie
The Unstable version; this is always called Sid

Each stable release seems to have a [stable] life of about 2 years. Wheezy was released in May 2013, and Jessie development has now been frozen. So we can probably expect Jessie to be release (i.e. as a stable distribution) in the first half of 2015.

So for anyone experimenting with the RaspberryPi, now is probably a good time to install Jessie. The Jessie repository also includes newer versions of the applications included with Raspbian.

Synaptic Package Manager on Jessie


For example, only Gambas 3.1.1 is available on Raspbian Wheezy, while version 3.5.4 is available on Raspbian Jessie.

Install or upgrade?


I understand you can use the unattended net installer to install a fresh copy of Jessie. But I decided to upgrade an image that I had broken while trying to get the Jessie version of Gambas to run on Wheezy (it did actually run OK, until I re-booted the system ....and then the desktop wouldn't load properly). However I was able to use <ctrl><alt><F2> to launch a terminal and run the following procedure.

Start by editing the sources.list file using your preferred editor as root. If you are running the desktop, you can do it like this:-

sudo leafpad /etc/apt/sources.list

But if you can only run commands (e.g. you broke the gui desktop, as I did) you may have to use nano:-

sudo nano /etc/apt/sources.list

Any mention of wheezy in this file should be replaced by jessie, so:-

deb http://mirrordirector.raspbian.org/raspbian/ wheezy main contrib non-free rpi

...would be changed to:-

deb http://mirrordirector.raspbian.org/raspbian/ jessie main contrib non-free rpi

Now do the update/upgrade thing:-

sudo apt-get update
sudo apt-get upgrade

...and then upgrade the distribution:-

sudo apt-get dist-upgrade

During this procedure you will be prompted to answer lots of silly questions. I say "silly" because my 2 digit IQ means I don't understand the questions, so mostly I just accept the default/suggested answers.

I don't know how long this process takes, I just kicked it on each time I passed by the Pi and noticed it was hungry for input. So allow at least 4 hours for this upgrade.

If you have just one RaspberryPi and it is "mission critical" in some way, this might not be the best time to upgrade to Jessie. But SD cards are cheap, so why not try this on another card?

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