persisting a ramdisk

Bill McGonigle bill at
Wed Jul 15 18:23:07 EDT 2009

Hi, all,

This is my first post to the list and I'm new to kexec.

I'm wondering if it's possible to persist a ramdisk across a kexec
'reboot'.  In the normal reboot case, this isn't possible as the BIOS
may do who-knows-what to memory, but if I understand correctly, this
isn't a problem in the kexec case.

I'd imagine there would have to be a certain memory marker or a kernel
command line option so that the new kernel could find the ramdisk.  I
figured this might exist already, but I probably don't know enough to
find what I'm looking for.

The use case here is booting from a LiveCD, fetching a more-current
kernel and tools off the Internet, and then booting into it.  I'm not
really sure if having the kernel on the ramdisk makes it harder or not
(it would still be worthwhile for non-kernel data).  Some of the kboot
docs make me think it could be possible, but I don't understand the
hand-off mechanism for resources handled by the previous kernel.

If anybody knows if this is doable please point me in the right
direction, or to docs I ought to be reading to better understand the


Bill McGonigle, Owner           Work: 603.448.4440
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