internal parts of floppy disk drive?

Answer 1

Basics:
A constant speed motor to spin the diskette
A stepper motor controlling the precise position of the read head in relation to the data sectors on the diskette.
The read head which reads the magnetic field changes that relate to binary data stored on the diskette.
IC Chips controlling the flow of data to and from (Write or read) the floppy drive to the system bus.