dd: /dev/cd0: Invalid argument

Christoph Kukulies kuku at kukulies.org
Sun May 3 19:56:20 UTC 2020

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 .


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