dd: /dev/cd0: Invalid argument

[Arne Steinkamm]

Hi,

On Sun, May 03, 2020 at 09:56:16PM +0200, Christoph Kukulies wrote:
> I got a bit further with seeing my old SCSI-Periphals on the external SCSI bus connected to the sym0 (ASUS SC-200 Interface).
> 
> I can dd one of the disks connected there (/dev/da0) completely (2GB)
> 
> But I cannot dd if=/dev/cd0 of=cd_dump 
> 
> Doing this, I???m getting 
> 
> $ dd if=/dev/cd0 of=cd_dump
> dd: /dev/cd0: Invalid argument
> 0+0 records in
> 0+0 records out
> 0 bytes transferred in 0.000199 secs (0 bytes/sec)
> $ 
> 
> What???s wrong? /dev/da0 and /dev/cd0 are both character devices. I can well cat /dev/cd0 >dump .

The blocksize of CDs is 2k so use 2k or a multiplier of it.

  dd if=/dev/cd0 ibs=2k of=cd_dump

.//. Arne

-- 
Arne Steinkamm         | Home:     Mail: arne<at>steinkamm<dot>com