Magnetic storage is read by a head detecting the magnetic fields of the stored data bits, which induce electrical signals that are then interpreted.
The fundamental process relies on the interaction between the magnetized areas on the storage medium and a specialized read/write head. As described in the reference, the read/write head moves over the magnetised areas.
Here's a breakdown of the reading mechanism:
- Head Movement: The read head, an electromagnetic component, is positioned closely over the surface of the magnetic medium (like a hard drive platter or magnetic tape).
- Field Interaction: As the head passes over areas that have been previously magnetized to represent data (bits), the magnetic fields from these areas interact with the head.
- Current Induction: This interaction is key: the magnetic fields they generate induce a small electrical current in the head. This phenomenon is based on Faraday's law of induction, where a changing magnetic field through a coil (part of the read head) generates an electrical current.
- Signal Detection: The storage device is designed to detect these tiny electrical currents. The characteristics of the induced current (such as its polarity or strength over time) correspond directly to the pattern of magnetization left on the surface.
- Data Interpretation: By detecting these currents, the device can determine the pattern of 1s and 0s that represents the stored data. For example, a magnetic field pointing in one direction might induce a positive current pulse corresponding to a '1', while a field in the opposite direction might induce a negative pulse corresponding to a '0'.
Through this precise detection and interpretation of the induced electrical signals, the stored binary data can be successfully read from the magnetic medium.
