I believe ATA laptop hard drive (at least that is what all of the other ketron's are).

Do you have the Midjay 1 or plus? I'm not sure if the new hard drive will read anything larger than what's already installed, 20 gig. That was one of the reasons why the plus was released. Also be very very carefull on how you instal the ribbon cable with the correct config of pins (1-44. if not you will burn out the hrd drive controller board.

AJ or Dan01 would know better.