The PCB

The 500GB Barracuda 7200.9's PCB is pretty small, occupying less than half of the drive's underside.

It's populated by two main chips - the hard drive controller and the motor drive controller.

The Hard Drive Controller

The 500GB Barracuda 7200.9 hard drive uses what appears to be a custom-made hard drive controller from Agere Systems.

We couldn't find out anything about this controller, even after searching through Agere Systems' website. But this hard drive controller should not differ much from others in its job of managing the transfer of data between the drive and the host.

The Motor Drive Controller

In this drive, Seagate used a separate motor drive controller from Texas Instruments. Again, this appears to be a custom chip, made specifically for Seagate.

Although it cannot be confirmed, this motor drive controller is likely to employ pseudo-sinusoidal drive technology, similar to ST's proprietary Smooth Drive technology. Such technologies allow the hard drive to minimize torque ripple to reach a higher track density as well as reduce acoustic noise.

The Cache Buffer

The 500GB Barracuda 7200.9 comes with 16MB of buffer memory. But where's the SDRAM chip?

The empty solder points for the SDRAM chip were conspicuous on the PCB. No sign of the SDRAM chip on this side of the PCB. It should be hidden from view on the underside of the PCB.