On Sat, Mar 31, 2001 at 01:59:20PM -0800, Mike Cheponis wrote:
>
> Why is the performance of "cp" and "cat" so poor compared with "dd"?  -Mike
...
> # time dd if=/dev/rwd0e of=1g bs=4096k count=256
...
> # time cp 1g 1g.cp 
...
> # time cat 1g>1g.cat
...
> # time dd if=1g of=1g.dd bs=4096k

The primary difference is that, because dd is using a much larger block
size, it can do much more I/O between disk seeks.