hard disk magnetic head is the key component of hard disk reading data. Its main function is to convert the magnetic information stored on the hard disk into electrical signals and transmit them to the outside. Its working principle is to read and write the data on the disk by using the principle that the resistance value of special materials will change with the magnetic field. The quality of the magnetic head largely determines the storage density of the hard disk. At present, GMR (Giant

Magneto

Resilient) magnetic head is commonly used. GMR magnetic head uses materials with better MR(Magneto

Resisive effect and multi-layer thin film structure, which is more sensitive than the traditional magnetic head and Mr (Magneto

Resilient) magnetic head. Relative magnetic field changes can cause large resistance value changes, thus achieving higher storage density.

Magnetic head is a hard disk. A magnetic head is made by winding a coil around a magnetic core. When the hard disk is working, the magnetic head reads data by sensing the change of magnetic field on the rotating disk; Write data by changing the magnetic field on the disc. In order to avoid the abrasion of the magnetic head and the disk, the magnetic head is suspended above the disk rotating at high speed without direct contact with the disk. Only after the power is turned off, the magnetic head will automatically return to a fixed position on the disk (called the landing zone, where the disk does not store data, but is the initial position of the disk).

due to the working nature of the magnetic head, the requirements for its magnetic induction sensitivity and precision are very high. Earlier magnetic heads were made of ferromagnetic materials, which were not ideal in magnetic induction sensitivity. Therefore, the storage per disk of early hard disks was relatively low, while the track density on storage per disk disks was high, and the magnetic head induction was not enough, so it was impossible to accurately read data. This resulted in the limited capacity of early hard disks. With the development of technology, the magnetic head has made great progress in magnetic induction sensitivity and precision.

At first, the magnetic head had the functions of reading and writing together, which required a high level of manufacturing technology and technology of the magnetic head. For personal computers, in the process of exchanging data with the hard disk, reading data is much faster than writing data, and the characteristics of reading and writing operations are completely different, which leads to the magnetic head with separate reading and writing functions, which work separately and do not interfere with each other.

source: IT terminology.