The read/write heads are U-shaped pieces of conductive material. Hard disks have parallel tracks across the width of the media and the read/write heads take time to switch between tracks and to scan within tracks. Different spots on the storage media take different periods of time to access. For a hard disk this time is typically less than 10 ms. Defragmentation of the hard drive can improve the performance of a computer.

Types of heads used in hard disk design

  • Ferrite
  • Thin-Film
  • Metal-In-Gap
  • Magneto-Resistive

Giant Magneto-Resistive (GMR) Heads

In 1997 IBM introduced the giant magneto-resistive (GMR) head. These are structured as a space layer of non magnetic material between two magnetic layers. Manganese Ferrite (MnFe) is used as an exchange film.

Amazon Books
Image of Building the Perfect PC
Author: Barbara Fritchman Thompson, Robert Bruce Thompson
Publisher: Maker Media, Inc (2007)
Binding: Paperback, 432 pages