Paging to a regular file

From http://www.cyberciti.biz/faq/linux-add-a-swap-file-howto/:

cd /
dd if=/dev/zero of=/swapfile1 bs=1024 count=262144
mkswap /swapfile1
chown root:root /swapfile1
chmod 0600 /swapfile1
swapon /swapfile1
vi /etc/fstab:
   /swapfile1 swap swap defaults 0 0