Enhancing cdboot [patch for review]

[Jonathan McKeown]

On Thursday 11 December 2008 14:42:46 Giorgos Keramidas wrote:
> On Thu, 11 Dec 2008 10:52:49 +0200, Jonathan McKeown <jonathan at hst.org.za> 
wrote:
> >> cdboot runs long after the prompt for BIOS setup.  I don't think we
> >> can modify cdboot to add serial console support to systems whose BIOS
> >> setup doesn't support it.
> >
> > Sorry, of course you're right: I'm talking nonsense.
> >
> > It's the stage immediately after that that isn't available. I wish I
> > could remember why I thought that had caused me a problem once.
> >
> > Certainly there's a big chunk of the boot process that is accessible
> > through a serial console on a disk-based boot that's not available on
> > a serial-console boot.
>
> I'm still not sure what sort of `serial console boot' we are talking
> about here.  What's the difference between a `serial console on a
> disk-based boot' and a `serial console boot'?

Sorry, there's been an element of ``ready - fire - aim'' about my messages 
today - I'm trying to do several other things at once.

Let me get a serial-boot CD out and play with it - it's a while since I did a 
headless install so I'm working from a vague memory.

I think what I'm saying is that there are several stages in the boot process; 
when booting from a hard drive and using a serial console, all the stages are 
accessible: but when booting from a CD, only the last stage is.

I seem to remember that causing me a problem with a headless machine once upon 
a time (perhaps there was an error at an early stage, with the first hard 
drive failing, and I couldn't see loader(8) to tell it to boot off the second 
drive which was a mirror of the first?).

Certainly I've taken part in a couple of discussions in -questions over the 
last year or two in which people want to know how to make a serial-capable 
install CD - which is not as straightforward as it might be if there were a 
serial-capable cdboot (along the same lines as putting boot0sio instead of 
boot0 on a hard drive).

Jonathan