Messages in this thread | | | Date | Wed, 2 Jun 2004 08:39:15 -0400 (EDT) | From | "Richard B. Johnson" <> | Subject | Re: How come dd if=/dev/zero of=/nfs/dev/null does not send packets over the network? |
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On Wed, 2 Jun 2004, Piszcz, Justin Michael wrote:
> root@jpiszcz:~# mkdir /p500/dev > root@jpiszcz:~# mount 192.168.0.253:/dev /p500/dev > root@jpiszcz:~# echo blah > /p500/dev/null > root@jpiszcz:~# ls -l /p500/dev/null > crw-rw-rw- 1 root sys 1, 3 Jul 17 1994 /p500/dev/null > root@jpiszcz:~# dd if=/dev/zero of=/p500/dev/null > > 6179737+0 records in > 6179736+0 records out > > Instead it treats it as a local block device? > > Kernel 2.6.5. >
First, /dev/null is a device file. Can you access a remote device over nfs? ... like
mount chaos:/dev/ttyS0 /mnt cat "foo" >/mnt
I think not. Yes it's the exact same thing; /dev/null is a character device just like /dev/ttyS0, but a bit dumber. The above used the network to make the essential equivalent of a sym-link. The open of the device-file, the connection of the major-minor numbers to the resulting file descriptor occurred on your local system.
Cheers, Dick Johnson Penguin : Linux version 2.4.26 on an i686 machine (5570.56 BogoMips). Note 96.31% of all statistics are fiction.
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