HDI - Head to Disk Interference.

Yes, data is written to and read from a floppy disk using a magnetic read/write head that interacts with the magnetic coating on the disk. When writing data, the magnetic head aligns the magnetic particles on the disk surface to represent the information. When reading data, the head detects the magnetic orientation of the particles to retrieve the stored information.

Read/write actuator

A hard disk drive (HDD) stores data in magnetic form by magnetizing tiny areas on a spinning disk. It uses an electromagnetic read/write head to read and write data by detecting the magnetic orientation of the areas on the disk.

no, the head not touching the surface of the hard disk. If it touch the great chance of data may be lost. only the head of floppy disk is touch the surface of the disk.