Not booting: Kernel panic: VFS: unable to mount root fs
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Not booting: Kernel panic: VFS: unable to mount root fs
Hey
I have been trying for a week to get any linux distro installed on my Proliant 2500 with 64Mb ram and 200mhz pentium pro, with scsi disks.
Gentoo keeps getting kernel panics or stopping GCC when it is compiling, RH and Suse both give the error that there is a compressed image on RAM0 and then they halt.
I finally tried with Knoppix (becuase i heard that you can also install it to the hard drive.
Now, when I booted knoppix first time, it gave me an error saying that it only had about 8000kb of ram. I thought this was weird, given that the Compaq screen when the computer boots up says that it has 65000kb of ram.
Anyway, I pressed "continue" and then it got errors about alloc_pages, which seem to be when the computer runs out of memory.
Then, I tried booting knoppix with the "mem=64M" option, because I have heard that it can forget about memory, sometimes. However, this resulted in an almost instant error of "Kernel panic: VFS: unable to mount root fs on 01:03".
Two questions: firstly, given the problems I've been having, and the fact that knoppix only thinks there is 8mb of ram, is it a correct assumption that it is the RAM which is causing all of my problems?
Secondly, how the hell can I get this thing to work?? I'm so unbelievably frustrated. I like gettign things to work, but this is just so difficult. Can anyone give me suggestions about why it isn't working?
It could be an issue with RAM, in fact, this exact thing happened to me this weekend. I had 2 sticks of 128Mg RAM in my machine, and the machine unexpectedly got hung up. Nothing I tried would fix it, so I rebooted. Still no joy, the kernel panicked, etc, etc, I try the rescue floppy, still no love, so out comes the trusty Knoppix disk. That allowed me to make further progress, but upon closer inspection I found that the system was only seeing 180Mg of RAM, not the 256 that it should. I removed one of the sticks, and bingo everything works OK again, although it's slower given the reduced memory.
Anyhow, the point is that your hypothesis about RAM being the culprit is worth investigating. Perhaps memtest86 would be worth checking out. Good luck with it -- J.W.
I tried running memtest86 from a gentoo disk. When it started it said that is was starting, then said something like
"Memory Test .... Ready!" and then it didn't do anything else.
I'm not quite sure it was doing it (it didn't look like it).
This seems to be a difficulty with many older servers. You need to append "mem" arguments to the kernel line to get all the memory recognized on boot.
There are several parameters you can try, depending on distro. I run Debian on 2 Proliants (2500, 6500) and this formula works for me:
mem=exactmap mem=640k@0 mem=(totalRAM-1)m@1m
You'd have:
mem=exactmap mem=640k@0 mem=63m@1m
You can also specify the RAM in Octal, if you prefer. Arguably that would give the Kernel a more precise count and location of the memory.
This is telling the kernel where the memory is in the logical registers, not the physical slots. mem=63m@1m tells the kernel that there is an additional 63MB of memory starting at the 1MB mark. F'rinstance, in my 2500 I've got 288MB in 3 DIMMs. So my mem argumets are:
mem=exactmap mem=640k@0 mem=287m@1m
Here's a nice overview of the several methods of specifying memory sizes: http://www.geocities.com/rlcomp_1999/memory.html?200515
I guess the detail spec is in hex, really. I always get confused as to which systems prepend 0x for hex and which use 0x for octal.
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