problem cleaning up old drive

[nepal google]

On Friday 21 Nov 2008, Hakan Koseoglu wrote:
> root at jupiter:~# dd if=/dev/zero of=/swapfile bs=1M
> count=1024 1024+0 records in
> 1024+0 records out
> 1073741824 bytes (1.1 GB) copied, 18.7898 s, 57.1 MB/s
>
> Which will create a 1GB file.

my free shows this;
nepal at kub:~$ free
             total       used       free     shared    buffers     cached
Mem:        515844     492236      23608          0      10280     349036
-/+ buffers/cache:     132920     382924
Swap:            0          0          0


I understand using dd as above, but does this way use 
1gb of my root partition?

the reason I ask is that the partitions on this drive are 
not in disk order and although I have about 40gb of 
unused space, I'm afraid of screwing up their references 
by adding another partition, but ideally I would prefer to 
have it that way. Sorry for my dumbness on this.

nepal.