The quality of the translation from German is such that it leaves you guessing as to what it really is they were selling.
But it seems they have a USB interface for Tyros which will allow to quote:
"Functioning
After installing the included drivers, the hard drive of your keyboard as a new drive to your computer visible. You can now directly on the hard drive of your keyboard access. Even the editing such as MIDI files and samples directly on your keyboard from their computer is now possible."

It's puzzling what is so special about it because all that seems possible with a direct USB connection from Tyros to PC anyway (with a Yamaha midi driver installed on the latter.)

The contents of the hard disc can be examined and edited (Explorer fashion on the PC) by setting Tyros to HDD mode. ie. Power off, push Music Finder button, power on keeping MF pressed till booting complete.
John

[This message has been edited by jwyvern (edited 07-26-2008).]