The Hard Disk Controller

The 120GB Momentus 5400.2 hard disk uses what appears to be a custom-made hard disk controller from STMicroelectronics.

We couldn't find out anything about this controller, even after searching through STMicroelectronics' website. But this hard disk 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

Seagate used a motor drive controller from STMicroelectronics. Again, this appears to be a custom chip, made specifically for Seagate.

The main advantage of using this chip is ST's proprietary Smooth Drive pseudo-sinusoidal digital drive technology. Smooth Drive allows the hard disk to minimize torque ripple to reach a higher track density as well as reduce acoustic noise.

The Cache Buffer

The 120GB Momentus 5400.2 comes with 8MB of buffer memory, courtesy of a single 54-pin TSOP II SDRAM chip from Samsung.

The Samsung K4S641632H-UC60 is a 64Mbit SDRAM chip rated at 60ns. It has a maximum bandwidth of 333MB/s at the rated clock speed of 166MHz.