USB memory stick or ext HD

Anyone tried to used an external usb memory pin or HD using a usb a/b converter or similar? Or just using a usb b - b cabel attached to an ext HD? I have an ext HD I would like to use in my setup.

I don't think that will work.
Your MPC does not act like a computer, it acts like a USB memory stick.

if you imagine two USB memory sticks plugged back to back with adapters, it's clear nothing is going to happen.
The MPC acts as a slave device, the computer has the brains to get it to do stuff.

You may be able to hook up your external hard drive to the internal hard drive connector if you have the correct cables and adapters, although I can't say this with any certainty at all!

Internal HDDs are cheap, just buy one.

exactly, it's a matter of host or client. the MPC is a client...

and adding the HD / RAM and JJ OS is like a +10 trainer on your fav video game.