On Thu, 24 Mar 2005 20:34:50 -0800 (PST), A <ahmedcali@xxxxxxxxx> wrote:
> Thank you. Using the kernel option root=/dev/hda5
> worked. The bootup progresses further. However,
> after a while the kernel freezes....
The whole Redhat philosophy revolves around coming up using an initrd
and then prepping the final real system - it's not trivial to avoid
this if you don't know what it wants to do.
Rough generic overview of the modern boot concept, not distribution
specific here:
* kernel starts
* mounts initrd and runs tiny init scripts in initrd
* scripts use minimal /dev entries via initrd
* initrd pivots in to new root and kicks off main boot
* udev builds full entries in the RAM filesystem living on /dev
* regular stuff starts up
> Warning: unable to open an initial console
There was no /dev entry for the console or other necessary devices and
udev didn't yet build those entries in the real filesystem (or even in
tmpfs).
> My question is, how can I tell if the devices in my
> machine are managed by udev?
Check whether udev is running, look at the output of "mount" to see if
/dev is living on a tmpfs or similar backing - I don't use RHEL much
so would need to check myself.
> And, do I "really" need an initrd file?
The short answer here is "yes". The longer answer is "no", but you'll
be pushing a really big bolder up a mountain if you don't know how
these bits fit together and try doing without.
> What is the connection between udev and initrd?
An initrd allows the kernel to come up in a minimal state without
loads of device support, udev populates /dev with entries as devices
come and go. They are useful together but are independent processes
which are present on a growing number of Linux based systems. Until
recently, udev wasn't being used in most cases where an initrd was.
> In my .config file, the following is stated:
> CONFIG_BLK_DEV_INITRD=y
> Does this mean that the kernel absolutely needs an
> initrd file, and if it cannnot find one, it will barf?
No. It can run without one, but you need to have your filesystem setup
to handle this and you don't - without modifying bits of your
distribution, you aint gonna get around it.
> Can I just unset the above?
You can, and if you really want to live without an initrd then please ask again.
Note also that this mailing list is mostly intended at kernel hacker
wannabes and is not a specific kernel support list - it's usually best
to ask your local LUG about such things.
Cheers,
Jon.
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