Subject: raw disk access under 3.0 i386 install CD
To: None <port-sparc@NetBSD.org>
From: Tom Uban <uban@ubanproductions.com>
List: port-sparc
Date: 04/24/2006 22:21:37
I have a pair of IDE hard drives and I want to do a raw copy
from one to the other, so I thought that I might just run the
3.0 install CD shell and dd from rwd0a to rwd1a. I know that
back in the dark ages, this was possible, but apparently in
these modern times things have changed. When I try to do this
I receive a read only error on the /dev/rwd1a device.

When the PC boots, the wdX information goes by to quickly to
read and the dmesg command is not present on the install CD
image.

Is what I want to do possible (anymore)?

FWIW: I experimented with linux doing this as well and it
appears that linux does not have a raw disk I/O capability
by default. After doing a bit of searching, I discovered that
there is some sort of rawio extention which allows a raw
device to be associated with a block device, but it also
said that dd would not work with this raw device due to
buffer alignment issues vs. DMA. Go figure...

--tnx
--tom