After reading the above posts, I began playing around with this myself. The only thing new I discovered was this:

use open IO => ":raw";
[download]

Adding the above made it abysmally slow!
Running it again under 'strace' made it clear why, the reads are done one byte at the time!
Anyone know a good reason why this would be so?

-- O thievish Night, Why should'st thou, but for some felonious end, In thy dark lantern thus close up the stars? --Milton