Date: Thu, 9 Nov 2006 12:00:13 +0100
From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: cyg mem limit or network failure? Other? dd(dsk->net).blksz>=64M:  Fail
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On Nov  9 00:56, Linda Walsh wrote:
> I was running some network bandwidth tests using "dd" (WinXP2/Cygwin)
> 
> I was timing copies of a 300MB file from local disk to a remote
> server.  The local computer has enough memory to hold the file
> in the memory cache once it is loaded.
> 
> I ran through increasing power-of-two block sizes from
> 512 bytes up to 512MB, where it, theoretically could read
> and write the file in one read and write for the whole file.
> Essentially (say "s:" is a network drive):
> 
> for (i = 512;  i<=512MB;  i = i*2) do {
>    dd  bs=$i  if=/tmp/input  of=/s/Video/output.dat
> }
> 
> Unfortunately, the test /fails/ at or above 64MB (actually at or
> above 65,005KB).  The ERROR message is:
> 
> dd: writing '/s/Video/output.dat': Resource temporarily unavailable

I tried this with a 120 Megs and 1.2 Gigs file and dd works with all
blocksize up to the tested 512 Megs for me.

Could this be a network issue with big blocksizes, maybe?


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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