http://www.pc.ibm.com/qtechinfo/MIGR-43803.html?up=unknownuser
>The following HDD models generate some clunk sounds.
>Model Capacity New Version Vendor
>------------------------------------------
>DK23DA-20 20GB A0B6 HITACHI
>DK23DA-30 30GB A0B6 or A0K1 HITACHI