concluding from dd raw dump size to disk mfgr

Christoph Kukulies kuku at
Wed Sep 30 12:59:36 UTC 2020

Thanks. In my case I didn’t have physical access nor any access to the system I took the dd dump from.
I thought just to identify the drive from the calculation of the dump size.

But meanwhile I identified a device that fits and that probably must have the type of drive I took the dump from:

Toshiba MQ01ABF050

> Am 30.09.2020 um 13:35 schrieb Polytropon <freebsd at>:
> On Wed, 30 Sep 2020 09:40:00 +0200, Christoph Kukulies wrote:
>> I made a dd dump of a raw disk device the other day. The size of the 
>> dump is exactly
>> 500107862016 bytes in size, corresponding to 997773168  sectors (512bytes).
>> I would like to dump this file back to a physical device. Best would be 
>> the one which fits exactly that size. Unfortunately I presently don't 
>> know what drive mfgr./type this corresponds to. Is there a way to find out?
> A convenient way is to use the following command:
> 	# diskinfo -v <device>
> Also check the corresponding entry in the "dmesg" output.
> Note that AF devices might prefer a sector size of 4kB (4039

What is „AF“ devices?

> instead of 512 bytes). When you transfer data back using dd,
> you can often choose a better suited block size, usually in
> the range of several MBs. :-)

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