Head Actuator

Figure 10-7.—A typical floppy disk drive. Drive Electronics Circuit Board Mounted to the disk drive is the drive electronics circuit board. This board contains the circuitry that (1) controls the electromechanical parts of the disk drive, (2) controls the operation of the read/write heads, and (3) interfaces the floppy disk drive to the disk controller in the computer. Connectors On the back of the drive electronics circuit board are at least two connectors. The 4-pin, in-line connector supplies power to the drive. The 34-pin edge connector provides control signals to the drive and exchanges data between the drive and the disk controller in the computer. Head Actuator The head actuator assembly is a mechanical motor assembly that actually moves the heads over the disk. It does this by using a stepper motor. This motor moves in very small fixed increments or steps. Each increment of the stepper motor defines one track; therefore, if we want to read data on track 20, and the heads are at track 10, the stepper motor must be incremented 10 times to reach track 20. Read/Write Head Assembly Floppy disk drives have two read/write head assemblies, one for each side of the floppy disk. The heads are mounted on arms that connect to the head actuator assembly. Since the heads are mounted to a single head actuator, they move in unison with each other. 10-9