How to create .iso file image of cdrom (atapi)?

Scott Mitchell scott+freebsd at fishballoon.org
Wed Jan 7 13:08:25 PST 2004


On Wed, Jan 07, 2004 at 06:05:47PM +0100, Hendrik Hasenbein wrote:
> Francisco Reyes wrote:
> >Other than speed is there any consideration about the buffer size?
> I assume you are referring to the 'bs=2048' argument to dd.
> The argument 'bs=2048' sets the block size to be used for the device.
> You can't use another value for cdrom drives than 2048 except you are 
> able to change the blocksize on the drive. Some can be jumpered for 512 
> per block, but there is no need to do that. If you use another value for 
> bs the operation will fail on a cdrom drive.

Well, you can use a bs value that is a multiple of 2048 (like the 64k in my
previous example).  Using a larger block size will generally speed up the
transfer, up to a point.

	Scott

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