Large Write_Andx messages

Mikael Klamra mklamra at
Mon Oct 29 19:18:25 GMT 2007

I was asking about chained WRITE_ANDX messages. Windows supports large
WRITE_ANDX messages when the messages contain only one block. However,
I want to chain several blocks in a message (i.e., use the batching
functionality of WRITE_ANDX). Windows Server 2003 seems to accept
WRITE_ANDX messages containing two blocks when the total message size
is up to about 4700 bytes. When the size gets larger, the server
returns a non-specific error code. This usually means that the message
has the wrong format or that a capability was not set. Does Samba use
the batching functionality of WRITE_ANDX? The Windows client does not
seem to use it.


On 10/29/07, Christopher R. Hertel <crh at> wrote:
> Jeremy Allison wrote:
> > On Mon, Oct 29, 2007 at 11:20:43AM -0700, James Peach wrote:
> >> The Mac OS X 10.5 client will do large reads and writes to Samba. The
> >> Samba support for this works perfectly well.
> >
> > He wasn't asking about large read/writes, he was asking about
> > chaining (andX) support.
> Actually, he's asking about both to some extent.
> He pinged me first in reference to my book and then also the jCIFS list.
> These are interesting questions, of course, but I think the original post
> slid a bit between CAP_LARGE_WRITEX and the idea of chaining WRITE_ANDX
> messages, thus the confusion.
> Chris -)-----
> --
> "Implementing CIFS - the Common Internet FileSystem"    ISBN: 013047116X
> Samba Team --    -)-----     Christopher R. Hertel
> jCIFS Team --  -)-----  ubiqx development, uninq
> ubiqx Team --    -)-----          crh at
> OnLineBook --   -)-----             crh at

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