Hard Disk Logic Board

All modern hard disks are made with an intelligent circuit board integrated into the hard disk unit. Early hard disks were "dumb", meaning that virtually all of the control logic for controlling the hard disk itself was placed into the controller plugged into the PC; there were very little smarts on the drive itself, which had to be told specifically how to perform every action. This design meant that it was necessary for controllers to be very generalized; they could not be customized to the particulars of a given disk drive since they had to be able to work with any type. Older drives were similar enough, and sufficiently undemanding in terms of performance that this arrangement was acceptable. As newer drives were introduced with more features and faster speed, this approach became quite impractical, and once electronics miniaturization progressed far enough, it made sense to move most of the control functions to the drive itself.

All modern hard disks have integrated electronics and controllers.

Today's hard disks contain logic boards. The logic board performs several important functions, and as hard disks become faster and more sophisticated, more functions are added to the logic board. This means the logic circuits need to be more powerful, to handle changes like geometry translation, advanced reliability features, more complicated head technologies, faster interfaces, and higher bandwidth data streaming from the disk itself.

Next: Control Circuitry