dd question

jd1008 jd1008 at gmail.com
Sun Sep 27 19:35:46 UTC 2015

On 09/27/2015 09:02 AM, William A. Mahaffey III wrote:
> On 09/27/15 09:49, Polytropon wrote:
>> Take the disklabel editor screen as an example. Make sure
>> 'c' is as big as the whole device, then take the end of
>> the last partition, 'a', as an offset, and add the desired
>> size for 'd'.
> Hmmmm .... My 'c' slice is *not* the size of the whole drive:
> [root at kabini1, /etc, 9:54:38am] 596 % bsdlabel da0
> # /dev/da0:
> 8 partitions:
> #          size     offset    fstype   [fsize bsize bps/cpg]
>   a:    1401120          0    4.2BSD        0     0     0
>   c:    1401120          0    unused        0     0     # "raw" part, 
> don't edit
> [root at kabini1, /etc, 9:54:44am] 597 %
> 1401120 (sectors) * 512 (bytes/sector) = 7.173734e+08 Bytes or 717-ish 
> MB (700.56 MiB), which is what I'm seeing out of my mounted drive, not 
> the 4-ish GB (3.61-ish GiB) it should be .... I'm guessing the drive 
> would boot & install OK, however it is convenient to be able to log 
> the proceedings in case of questions, that is what I am getting at ....
I already explained that since you dd'ed  the iso image onto the whole 
usb disk,
you end up telling the OS your usb drive is of the size of the iso file.
So, the rest of the drive is dotally invisible.

What you COULD have done is first partition the usb drive to have a first
partition to equal to the size of the ISO file, and then dd the iso file 
THE PARTITION< and not the whole drive.

If your BIOS supports it, you could then tell  bios to boot from the 
The rest of the USB stick's space would be available.

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