copy offload for SMB?

Christopher R. Hertel crh at
Fri Feb 22 09:49:06 MST 2013

Ah...  You're right.  There it is.  The notes show that CopyChunk was added
to W2K3, so it wasn't there in W2K or NT.  That's not quite donkey's years
but it is well more than a few Wildebeest's weeks.  :)


Chris -)-----

On 02/22/2013 10:42 AM, David Disseldorp wrote:
> Hi Christopher,
> On Fri, 22 Feb 2013 10:22:50 -0600
> "Christopher R. Hertel" <crh at> wrote:
>> On 02/22/2013 09:08 AM, David Disseldorp wrote:
>> :
>>> Server support is there, with a few quirks[1]. I'm not aware of anything
>>> pre-2k12 that uses it on the client side, but the ioctl itself has been
>>> around for donkey's years (SMB1), so there's likely something obscure
>>> using it.
>> David,
>> IOCTL handling in SMB1 is flaky at best.  I believe that the
>> NT_TRANSACT_IOCTL call works, but SMB_COM_IOCTL is hamstrung and
>> TRANS2_IOCTL2 was never implemented.  Do you have pointers to docs showing
>> when this IOCTL was introduced to Windows and/or how it was used?
> No, nothing aside from [MS-SMB].pdf.
> Cheers, David

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