This article offers a detailed introduction to magnetic head, including its main types and the issue head crash.
Hard disk head, a key component in hard disk, is used to read data.
Its main function is transforming magnetic information which are stored on the hard disk into electrical signal.
The hard disk head quality will affect the hard disk storage density.
Reading and writing operations are of different characteristics.
The magnetoresistive (MR) head owns detachable head structure.
The writing head in it uses the traditional electromagnetic head and the reading head applies the MR head.
As a result, it can be very sensitive to the changeable signals.
And the accuracy of reading data can also be improved.
In addition, the signal amplitude to be read has nothing to do with the track width.
Then the disk density will also be enhanced.
The MR head has been widely applied.
And the GMR which has better quality in magnetoresistive effect will be more popular in the future.
And the TFI head can be described as a winding magnetic core.
The induced voltage will be produced when the disk goes through the magnetic core.
With the improvement of magnetic sensitivity, the writing ability will be weakened.
Thus the reading head of the TFI will run of its ability.
In the mid 90s, the Seagate launched hard disk which is using AMR magnetic head.
AMR magnetic head adopts the TFI head to write, but uses thin magnetic materials to read.
The resistance of the thin strip will change according to the magnetic field.
And then generate strong signal.
AMR magnetic head further improves the surface density, and reduces the number of components.
Due to the limitation in AMR technology, it can support 3.3 GB/square inchs recording density to the most.
Thus the sensitivity of AMR magnetic head also has limitations.
It contributes to the born of GMR head.
Lets take a look at theSeagate 8TB NAS HDDif youre interested.
The GMR head is composed by 4 layers of conductive materials and magnetic thin materials.
The GMR sensor owns high sensitivity than the AMR head.
Thus it can improve the density and performance of the disk.
The head closely cling to the tape, and the induced current magnetizes the head, becoming a electromagnet.
Before recording, we should demagnetize the tape so as to thoroughly erase original signals.
When recording, the head is connected with microphone.
When playing, it is connected with horn.
Head Crash
A head crash is hard-disk malfunction.
And it happens when a hard disk read/write head touches its rotating disk platter.
A head often moves on a wafery veil of air flow that included in the surface of its platter.
What lies under is a layer of crackle carbon.
