max xmit default to 0x4104 (16644). Why ...

Jeremy Allison jra at
Mon Nov 3 06:23:59 GMT 2003

On Sun, Nov 02, 2003 at 08:28:44PM -0800, Richard Sharpe wrote:
> Hi,
> In tracking down a benchmarking problem, I discovered the following:
>         /* Was 65535 (0xFFFF). 0x4101 matches W2K and causes major speed 
> 	   improvements... */
>         /* Discovered by 2 days of pain by Don McCall @ HP :-). */
>         Globals.max_xmit = 0x4104;
> This causes me major problems and I was wondering why the previous value 
> (of 65535) caused problems with Win2K.
> I have not yet tested with Win2K and my testing has been confined to using 
> cifs_bm, but it also seems unlikely to be a problem on the surface. This 
> is the setting of the max amount data that Samba is capable of writing in 
> one go. If Windows does not like it, it is free to use a smaller size in 
> read(&X) requests if it likes to.

This is one of those numbers that W2K uses that seems
to cause their redirector to do different things if
it's changed. I can't get to my HP mail right now
but hopefully Don will chime up with the background.


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