[PLUG] Busted computer

John Jason Jordan johnxj at comcast.net
Thu Oct 18 17:34:03 UTC 2007


On 18 Oct 2007 04:40:29 -0700
Russell Senior <russell at personaltelco.net> wrote:

> Russell> That sort of sounds like the initrd (a kind of compressed
> Russell> image that becomes a ramdisk to help loading device drivers
> Russell> necessary for booting up) may be damaged or missing.
> 
> I decided to figure out about initrd's a little bit, having managed to
> remain mostly ignorant of them 'til now.  According to the mkinitramfs
> manpage, an "initramfs [or initrd] is a gzipped cpio archive".  To see
> the contents of a particular initrd, you ought to be able to get a
> listing with this command, e.g.:
> 
>   zcat /boot/initrd.img-2.6.17-2-686 | cpio -i --list -v | less
> 
> substituting your own initrd filename.  Or, actually extract it into a
> temporary directory, say:
> 
>   mkdir /tmp/my-initrd
>   cd /tmp/my-initrd
>   
>   zcat /boot/initrd.img-2.6.17-2-686 | cpio -i -v 
> 
> and see if it blows chunks in interesting ways.  If it extracts
> cleanly, then I guess it isn't corrupt.  In which case, look at the
> init you find there.  It's a shell script and fairly linear.  It might
> shed some clues.

Well, this morning I suddenly realized that the initrd files all had a
backup sitting right there, so why not try them? I didn't know why this
did not occur to me before. However, sadly, the .bak versions resulted
in the same kernel panic. 

	initrd.img-2.6.17-11-generic.bak
	initrd.img-2.6.20-15-generic
	initrd.img-2.6.20-15-generic.bak
	initrd.img-2.6.20-16-generic
	initrd.img-2.6.20-16-generic.bak

So then (using Slax) I unzipped them with Ark into Kate so I could view
them. They are all unreadable, but Kate announced that I should not
save the file because it is a binary file. I don't know what that is
supposed to look like, but there were only a few small sections that
were human readable, things like "qla24xx_get_isp_stats." The rest was
all upper ASCII junk.

Assuming this means they are corrupt, I decided I should just rename
them, then copy over from a full disk backup that I made a month ago.
Unfortunately, I did it over ethernet with nfs to my desktop computer
using cp and, for some reason that I do not understand, the
entire /boot folder is not there. Naturally, the one folder I need. If
I ever find that Murphy dude his ass is dead.

Googling on "initrd" tells me that apparently the initrd.img file is
for loading modules. If that's the case, then it will be unique to the
computer on which it is installed. In other words, I can't just grab an
initrd file from somewhere on ubuntu.com and slap it in my /boot
folder. I do have a couple of USB disks that I have used for backups in
the past, including one which I believe has a full tar image of my hard
disk and perhaps other backups. These would be old files, but I haven't
added any hardware to the computer, so the initrd files should be the
same, assuming I am correct about what their purpose is.

I need to study this some more to see what that kernel panic error
message is all about. I also need to get a large shovel for digging the
USB disks out of the closet where I think they are.

Meantime I am downloading Gutsy, both 32-bit and 64-bit. Evidently the
Kubuntu, Xubuntu and Edubuntu versions are not yet available, but at
least we will have copies of the standard versions for the Clinic on
Sunday. The download is slow, and there are no torrents. :(



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