The Hard drive needs to be below a certain size. In the X1 it could be 6gb, but certainly it will not work if the drive is larger than 20gb. It will probably ruin the hard disk too.

I would reccomend fitting a 6gb or less IBM or Hitachi Travelstar (if you do not want to buy a genuine Ketron Drive.)

The keyboard will detect and format the new hard drive on power up.