Hello, I'm Alan Pope, and welcome to this short screencast about the Ubuntu Repositories

This is the first in a series of short screencasts where we'll cover managing the software on the Ubuntu system. So that includes installing, removing and updating software packages.

In this first one we'll talk briefly about where the software in our system comes from.

You can see more of these videos at screencasts.ubuntu.com

Here's a fairly fresh installation of Ubuntu 9.04.

First exposure most people have to software management on ubuntu is update-manager

Update manager has started automatically showing that I have some updates waiting to be downloaded and installed

Where do these updates come from and how does my machine know where to get them? Let's go and see.

In update manager there is a Settings button which takes us to a program called 'Software Sources' (which was called software properties in previous releases). You can find it here under the System -> Administration menu too.

I'm asked for my password whenever I access software sources or try to update the computer. This is a security feature we will talk about in a later screencast.

The software sources window appears...

This configures where we get our software from, how often we check for updates, and what happens when updates are available.

By default the system checks for updates daily, and will cause update manager to pop up, prompting you to install them manually.

Alternatively you can choose to have the updates download in the background, and even have security updates applied automatically.

The repository is divided into sections which you can individually switch on or off.

The security section is ticked by default and contains packages which have had security updates since this release of ubuntu was released.

The updates section is also ticked by default and will provide fixes for serious bugs, which are not classed as security issues.

Proposed is not ticked by default and gets package updates before they hit the updates section. The intention is that users who enable this are getting pre-release packages and should be willing to provide feedback.

Backports contains versions of applications from a future release of Ubuntu, backported into this release. These are unsupported packages which may not have been thoughougly tested, and will likely change the functionality and user interface of applications.

Over on the 'Ubuntu software tab' the default is to get software from our nearest available mirror out of the 300 or so available worldwide.

You can change this to a different mirror here..

The Ubuntu standard repository has 'components'. Software is placed into a component by the developers on the basis of supportability and whether it meets the Ubuntu Free Software Policy.

In short main contains free software that is fully supported by the Ubuntu project. All the software pre-installed on the Ubuntu live CD is in the main component.

Restricted contains software which may be released under a non-free license, but is often a critical component for many users. Some of this may be on the Live cd, but will not be installed by default. An example is the nvidia 3d accelerated binary video driver.

Universe contains free software which is supported by the Ubuntu community, and whilst it has has no guarantee of support, security fixes or updates, the Ubuntu developer community is very active in keeping this component in check. This is a massive component containing a diverse range of software packages from many sources.

Multiverse contains software which is not licenced in accordance with the Ubuntu free software policy. This for example includes some games and system emulators as well as drivers from hardware manufacturers.

You can see the full definition of the components at this website, and this links to the Ubuntu Free Software Policy too.

If you're interested in downloading source code packages easily then this box enables that feature in the various package management applications. More on that and the other tabs in this screen in another screencast.

Now back to Update Manager, and I'll kick off the installation of these updates..   Thanks for watching.