Logic Board
The logic board is an intelligent circuit board integrated into the hard disk unit. This internal circuit board contains a microprocessor as well as other structures and its own internal memory. It functions like a small embedded PC within the hard disk itself and is even more complex than an entire PC from the mid-1980’s.
PC Logic Board
The control circuitry on the logic board performs many vital functions. These include:
 | Managing all read/write operations |
| Controlling the actuator’s movement to specific tracks |
| Managing internal cache |
| Controlling the spindle motor’s speed |
| Implementing power management features |
| Coordinating and integrating other functions |
There are two common interfaces for hard drives, IDE and SCSI. IDE or Integrated Drive Electronics is characterized by the placement of the control logic on the drive itself and not on a separate controller card. IDE interface can also be called AT Attachmentor (ATA) interface. The SCSI interface also uses drives with integrated controllers.