Oswald Jaskolla Software Development

The Singleton is a design pattern that can be used when you want to guarantee that there is only one instance of a particular class. Technically it is quite a simple pattern, involving only one class. Usually it is implemented like this:

OpenID is a way to authenticate oneself to different sites with a single account. This works by making use of HTTP redirection. The following sequence diagram gives an overview of the general actions involved in authenticating users.

I recently tried to upgrade Feisty Fawn to Gutsy Gibbon. I don't like upgrading operating systems, I had some bad experience upgrading Windows 98 to Windows XP. Still I was a bit surprised that Ubuntu confirmed my resentments.