Re: [Qemu-devel] diskimage HOWTO

[Kevin Wolf]

Mulyadi Santosa schrieb:
> On Mon, Aug 24, 2009 at 2:48 PM, Kevin Wolf<address@hidden> wrote:
>> Bai Shuwei schrieb:
>>> Hi, All:
>>>   I want to build a test enviroment with QEMU and buildroot. But I don't
>>> know how to build the diskimage which same as linux-0.2.img offered by
>>> BUILD-ROOT. I build the diskimage following the
>>>    buildroot-2009.05/docs/README.diskimage
>>> <http://192.168.1.102/crosscopile/buildroot-2009.05/docs/README.diskimage>,
>>> but failure.
>>>
>>>    The bellow is my process.
>>>
>>>    # dd if=/dev/zero of=img bs=4096 count=16384
>>>    # echo -e "n\np\n1\n\nw\n" | fdisk -C 16065 -H 255 -S 63 ./img
>>>    # losetup -o 512 /dev/loop0 img
>> This looks like the wrong offset. The first partition usually starts at
>> sector 63.
> 
> I agree, perhaps Bai should instead use 32256.
> 
> From "man losetup":
> -o, --offset offset
>               The  data start is moved offset bytes into the specified file or
>               device
> 
> So it has to be converted into bytes.
> 
> Bai, that could be the answer. Please kindly try it.

You shouldn't have removed half of my answer. Using kpartx is so much
easier than fiddling around with offsets.

Kevin