This Seagate 73090412 FSD II 340MB HDA - Proprietary Rare 8 Inch Hard Drive is an old mainframe hard drive used by the AT&T company data centers. It has a proprietary interface and cannot be tested or used without special hardware. We don't have the special hardware so we are unable to test it ourselves. We did get this drive from CAMEX in Camarillo Ca. who was a refubishiment company of these drives. This drive was in the refurbed cage at the time of the liquidation of the company. So we believe it works but cannot test it first hand.