Re: simulating dd with grub

[Yoshinori K. Okuji]

On Friday 21 October 2005 11:24 am, adrian15 wrote:
> Let's do the following with Linux:
>
> dd if=/dev/zero of=./blank.img count=1 bs=446
> dd if=./blank.img of=/dev/hda

You must not forget the last 2 bytes as well (the signature).

> My first instict, my first thought was to do:
>
> install p /boot/grub/blank.img INTO (hd0)

It is not a good idea to reuse install for this purpose, because install does 
much more than just copying.

>  1)  When Grub embeds an stage1  image into the MBR does it copy it into
> the 1st 466 bytes or not? And... why its size is 512 bytes instead of 466
> bytes as in my scheme?

It is not only the first bytes, but also the last bytes.

> 2) Can I make a fake blank.img which is approved as a good grub stage1 by
> grub itself?

Possible, but not the right way. The right way is to add a different command 
for it. However, since this is a new feature, this won't be included in GRUB 
Legacy.

Okuji