[Desktop12.04-Topic] Handling Failure Gracefully

[Robert Ancell]

Late topic...

In the real world there are always going to be failures, triggered by
things like software bugs, hardware failures and misconfiguration. 
Ubuntu should where possible handle common failures and provide
predictable feedback to the user that the system is broken.

I think we have the intention that most of this should work already, but
it would be good to check we've worked out the right failures to handle
and to methodically test they all work in 12.10.

Some common failure cases and what should happen:
- Failure to start X server - Run failsafe X server
- Failure to start any X server - Show error on text console
- Failure to start greeter - Run X server with error message
- Failure to start session - Return to greeter with error message
- Failure of compiz/unity during session - restart compiz/unity
- Failure to start application - show error message
- ...

--Robert