Re: ramdisk
From: Bill Davidsen
Date: Mon Sep 03 2007 - 19:20:30 EST
Xu Yang wrote:
thanks for the reply.
no , it is not decompressed. isn' t the kernel supposed to do that? As
we have tried to load this filesystem on the pc, it turns out the the
kernel can recognize it.
concerning the root=/dev/ram0,
as the default value is root=/dev/nfs, so I just modify the nfs to
ram0. is this might be a problem?
Hopefully someone who works with this regularly can provide some
answers, the only time I used booting into a RAM-only system the tools
which I had "just worked" and I followed the steps outlined without
fully understanding the details. However, I just tried loop mounting a
compressed filesystem and that didn't work, while decompressing into a
ramdisk and mounting worked fine. That's why I asked if your tool was
just copying to RAM without decompression, since I have no ides what
tool you use.
As for the name, your original post used "dev" without a leading "/" and
while I assumed it was a typo, I thought it was worth mentioning since
you were looking for suggestions. I would expect /dev/ram0 to be correct.
I would try the decompressed image next, and I have no other ideas at
the moment.
regards,
2007/9/3, Bill Davidsen <davidsen@xxxxxxx>:
Xu Yang wrote:
Hi everyone,
I want to use ramdisk to boot my filesystem, as I can't use NFS and harddisk.
I have load the ramdisk into the ram memory (start address :0x4000000)
and in the boot options I specified : root =dev/ram0 initrd=0x4000000
but the kernel said it can not find any file system on it.
Looking at the information below, did the program which loaded the
filesystem into RAM decompress it? It noted that it was compressed so I
would assume so, but I am unfamiliar with ARM tools, so I ask the
question. Also, should the boot device be "/dev/ram0" rather than
"dev/ram0" or is that correct for your system?
Here is the information I can supply :
U-Boot 1.2.0 (Aug 31 2007 - 20:54:55)
*** Auto-detects ethernet chip ***
DRAM: 0 kB
## Unknown FLASH on Bank 1 - Size = 0x00000000 = 0 MB
Flash: 0 kB
*** Warning - bad CRC, using default environment
In: serial
Out: serial
Err: serial
Hit any key to stop autoboot: 0
## Booting image at 00007fc0 ...
Image Name: Linux-2.6.19-arm2
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 740372 Bytes = 723 kB
Load Address: 00008000
Entry Point: 00008000
OK
## Loading Ramdisk Image at 04000000 ...
Image Name: ramdisc
Image Type: ARM Linux RAMDisk Image (gzip compressed)
Data Size: 12582962 Bytes = 12 MB
Load Address: 04000000
Entry Point: 04000000
Starting kernel ...
.........................................................................................
RAMDISK driver initialized: 16 RAM disks of 10240K size 1024 blocksize
<6>loop: loaded (max 8 devices)
<6>mice: PS/2 mouse device common for all mice
<6>VFP support v0.3: implementor 41 architecture 1 part 20 variant b rev 3
No filesystem could mount root, tried: ext2 cramfs vfat
<0>Kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block(1,0)
Who can give me some hints ? or point me some direction to handle this.
I appreciate this very much.
regards,
Yang
--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
--
bill davidsen <davidsen@xxxxxxx>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
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