Hi Tony, the Tyros will accept just about any generic 'off the shelf' HD which meets the following criteria:

2.5 IDE
Height 12.7 mm max
40 GB max

You're in luck , as the Toshiba MK4025GAS most definitely meets all of the above Tyros HD specification criteria: http://www.bananapc.com/products/productInfo.aspx?category_id=1091&product_id=6693

I know you're going to really appreciate the onboard storage advantage of an internal 40 GB HD on your Tyros. I can guarantee you'll NEVER fill it even close to capacity (I certainly haven't mine) because Yamaha & midi files are so small.
Enjoy. Scott