Grub and Plymouth

[Adam Pribyl]

On Thu, 16 Oct 2008, Adam Jackson wrote:

> Since it is, in general, impossible to know how long service startup
> will take, we lie.  We record the time it took to boot last time and run
> the progress bar against that.  There's a detail here which is that you
> can't know that until you've mounted /, so we estimate something really
> long initially and then once we load the time off the disk we lerp
> between the estimate and the recorded time.

I think this is a good way. There are some drawback we already discussed 
in bug #467100 - e.g. live CD.

> We also cheat in that the growth of the progress bar is intentionally
> nonlinear, growing faster early and then slowing down towards the end.
> This fools your brain into thinking it's going faster than it really is.
> Usually the math works out such that you'll see the bar fully complete
> for a second or two before switching to gdm or text console.  But,
> sometimes much longer, if this boot happens to take ten seconds longer
> than last one then there's just not much we can do about that.

I think this is also a good approach.

Today I however found one more problem with text based plymouth - this is 
when the system boot fails - e.g. because it is not able to mount root 
partition, then progress bar continues silently until the end and there 
is no way how to found what got wrong. Yes there is one - reboot and 
remove rhgb option in grub shell.. should I mention that when users asks 
me, that his Fedora is not booting, my first question is - where does the 
boot stop? With plymouth his answer will be useless, not to mention he is 
not able to find any reasonable help based on symptoms..

So there is still a way to go with plymouth..

>
> - ajax
>

Adam Pribyl