What a bad hard drive head performance

The head of the hard disk platter is a tool to read and write the work, the hard drive is one of the most sophisticated parts.
A head coil wound around the core made.
Hard at work, the head to read the data by sensing changes in the magnetic field rotation on the disc;
writes data by changing the magnetic field on the disc.
To avoid wear of the head and the disk, in working condition, the magnetic head floating above the platter rotated at high speed, without direct contact with the disc.
Sensing the degree is not enough, you can not read data accurately.
What are the performance hard disk heads have broken?
1, the system blue, suggesting disk error;
2, when the computer is started, the BIOS can not recognize the hard tips;
3, hard disk regularly issued
Kaka Ka "abnormal sound
4, a hard disk regularly issued
abnormal sound of beep beep;
5 , does not turn hard power (motor damage or damage to the circuit board);
6, hard power rotated automatically stop a few seconds;
7, a large amount of regular hard disk bad sectors;
avoid repeated after power to the hard disk head crash, to prevent scratching the head disc, causing irreparable damage