I am unable to find any online help for the following problem. I am trying to make a disk image copy on OpenBSD from one disk to another.

On Linux, this is how I would do it:

dd if=/dev/sda of=/dev/sdb

Unfortunately, the OpenBSD equivalents of the two disks, such as sd0 and sd1 have no entries in the /dev directory, only their partitions, therefore I am unable to reference them by path as seen above.

So how can I reference the DISKS path in OpenBSD commands, instead of their partitions path?

Naturally the disk controller and all connected disks are recognized by the OS and everything is fully operational.

  • HI @Tony - are you trying to make a copy of the first disk, or an image of the first disk (the former destroying the second disk, the latter adding as a file to the second disk)??
    – Mr R
    Commented Mar 25, 2022 at 0:51

1 Answer 1


On OpenBSD, the c partition is the entire disk (see the FAQ for details), so in your case, you'll want to read from sd0c and write to sd1c. Also, you'll probably want to use the block devices (rsd0c and rsd1c) instead of the character devices (sd0c and sd1c).

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