Kernel Panic on boot.

[bkm]

Greetings All,

I found a small stack of old laptops (ThinkPad 600x) that I wanted to make useful again. I am going to try to set them up for Ham Radio use for a few friends locally. I downloaded the v5.5 of Tiny Core and Core Plus. The Tiny Core boots but the Core Plus has a Kernel Panic error. These laptops all have hard drives and 320meg of RAM. I wanted to use the CorePlus distro because it had all the tools for setting us the laptops. Anyway... the error reads like this:

.Decompressing Linux... Parsing ELF... done
.Booting the Kernel .
.Kernel panic - not syncing: VFS: unable to mount root fs on unknown-block(2,0)

This occurs on all three laptops I have tried and yet the regular Tiny Core live cd boots just fine!?!

Any ideas? What might I be missing here?

I have re-burned the disk several times and checked it against the MD5 code and everything looks good. Any help would be greatly appreciated.

Thanks,

BKM - KJ4WRD

[Misalf]

No idea why the two ISOs behave differently, but I'm sure you could just install using TinyCore-5.4.iso and when done, copy over all extensions from CorePlus-5.4.iso since kernel and initrd are identical - only the boot loader entries are different.

[bkm]

Ha ha ha.... If only the mystery ended there.

It turns out the 4.7.6 and 4.7.7 core plus CDs both generate a 'unpacking error - system halted'

I gave up and used the tiny core 4.7.6 live CD to boot, downloaded the tc-install.tcz and started from there. Of the 4 different versions of core plus CDs I tried, none would work on these laptops.

At least I was able to get something started. It just took a lot longer than it should.

It seems strange that all the tc live CDs I tried worked and all the core plus CDs failed for various reasons specific to each version. Very weird indeed.

Thanks. This one will just leave me stumped I guess.

BKM

[curaga]

The first error indicates the initrd was not loaded, the unpacking error points towards faulty hardware. The thinkwiki page indicates official maximum RAM is 288mb, so your config seems to be more than the hardware can handle.

http://www.thinkwiki.org/wiki/Unofficial_maximum_memory_specs

[bkm]

Well, I didn't think the memory size would be a problem since it worked with a Lubuntu install. Son to be sure I removed one men card and reduced the total to 192mb. Still get the same error.

I also booted these disks on 3 different laptops of the same model and configuration. All three exhibit the same errors. Seems extremely unlikely that the same hardware malfunction or error could exist on all of the laptop examples. Since I had a a stack of 7 identical laptops, I tried all of them. All failed exactly alike.

The think wiki does not list an unofficial mem limit for this model. Only the official limit of 288. When the laptop was released there were not higher density ram cards available but the PC was built with the sa,me men controller as their big brother desktops, so when the higher capacity cards came out the following year, they plugged in and worked fine.

I don't buy the idea of the unpacking errors are hardware related because they occur on all examples of this PC.

Again, I don't really care about the error at this time since I worked around them, but I posted this hoping it might trigger an idea with one of the developers around the differences between the tc live CD and the core plus CD that might be causing this. I just wanted to alert to the possibility of the two different CDs using very different resources on the PC.

BKM

[curaga]

Well, the unpack error is pretty clear. You're also right that seven laptops rules out faulty hw as in broken; but it seems to be limited by design instead.

Perhaps the bios cannot setup enough memory even though linux can, and so the bootloader fails with bigger initrds. Just conjecture, but it's clear there's some kind of limit in that model.

[bkm]

Yeah, I kind of thought the same thing, but I couldn't imagine a situation where the system would fail when booting the same kernel. There is obviously something going on, I just can't imagine where it hiccups. Maybe something off in how the BIOS allocates buffer space for the cd-rom.

The weird part is that I eventually got a system running (frugal Install from tc live) just fine with some special packages I wanted. Once I figured out how to get my stuff configured just right, I went ahead and loaded up all the packages I could find in the coreplus listing just to see if there was some theoretical limit to how much the laptop could process on boot. It booted just fine from the hard drive.

I'm not sure what that leaves, but I am ok with being stumped. Some things are not worth getting a headache. So, it was a learning experience.

BKM

[bmarkus]

Can you try 6.0alpha1?

[bkm]

Sure, why not. I will download the images and try them on one of these laptops today. I will let you know what happens.

BKM

[bkm]

Bela,

Here is what I got. The CorePlus 6.0alpha1 boots with the following messages:

.Loading     /boot/vmlinuz......
.Loading    /boot/core.gz.........ready.
early console in decompress_kernel
.
.Decompressing Linux...     Parsing ELF...    No relocation needed...    done.
.Booting the Kernel .
.Kernel panic - not syncing: VFS: unable to mount root fs on unknown-block(2,0)
.Kernel Offset:  0x0  from 0x0100000  (relocation range 0xc0000000-oxd47cffff)

The messages are the same for all 13 menu selections (including the command line only option)
I could possibly edit the boot string using the <tab> key if you have something you want to try.
This was the same on all three IBM ThinkPad 600x candidates with 320m RAM.

Next...
I booted the TinyCore 6.0alpha with no errors. I tried it with all 4 menu options and they all booted fine on all three candidates.

The only thing I can 'see' that is different is that the Core+ tells you the media will not be removable and TC tells you that it can be removed. However, if you try to remove the CD after the TC boot, the drive will not open. If you try to remove the CD after the kernel panic on the Core+ boot, it opens with no problem. I also noticed this with both the 4.x and the 5.x versions as well. There is certainly no apparent reason for the Core+ to generate a kernel panic when it is only trying to boot the command line only option!

Hope that helps,

BKM

[gerald_clark]

I suspect Curaga is correct in reply #5.

[bkm]

Well... Maybe. But I would have thought the booting and installing of a Lubuntu distro on the same laptops would have attempted to load way more in the way of initial file systems in order for it to run the install process. The Lubuntu worked just fine. It was just way to slow to be useful.

I am beginning to think is has something to do with attempting to prevent the CD from being removed in the Core+ version. It seems to want to do that before it boots the kernel and that somehow trips up the boot process. Maybe the hardware is too slow and the CD drive is not finished with disabling the button before it tries to load the kernel. I just don't know.

Again, there is obviously some sort of limit to this particular model PC but I am just not to sure where that limit is being tripped.

BKM

[gerald_clark]

What prevents the CD from being removed is the fact that the first partition is mounted to access the CDE directory.
Nothing is done "attempting to prevent the CD from being removed".

---- Edit -----
Can these machines boot from USB?  If so:
Can you try a USB CD drive?
Can you try a thumb drive with the ISO dd'd onto it?

[Rich]

Hi bkm
You could try adding   debug   to the boot string to see if it spits out any additional information before it panics.