How does Hard Drive store info?

[umer007]

I have learned that the hard drive used "magnetic flux" to store information. Changes electrical signals to magnetic ones and stores them. Could someone please explain this process in detail, in a step by step way?

Help will be greatly apreciated.
Thanks in advance.

 

[Styx]

Well I dont know yr background so start from basics.

If you pass a current through a wire it will produce a magnetic field around it. If you apply the current the opposite way through the wire an opposite magneic field is made.

If you coil a wire like a cylender and pass current through it one way the magnetic field will go say left-to-right through the cylender. Pass the current the other way and the magnetic field will be right-to-left.


Imagine a cylinder of (soft) iron. If you apply a magnetic field from to to bottom it will be magnitiesed such - say north at the top.
If you magnetise it bottom to top such that the north pole it at the bottom.

By using a device called a "hall effect sensor" you can determine what way a field is flowing

so we have a way to write a field and a way of reading a field

Now if you define a north at top field as a logic databit "1" and a north field at the bottom as logic databit "0" you now have a way of defining what field means what.

If you make the cylenders of iron very small and allight millions of them in a disc so that the cylenders length makes up the thickness and the circle portion makes up the disc surface you have a magnetic platter.

Spin it really fast and have a very small coil of wire and a small hall effect sensor and bloody good position measurement you will be able to read/write induvidual magnetic cells.



They dont make a HD using cylenders they just make them out of some exotic material. But all magnetic materials have magnetic cells. The use of cylender analogy was useful for descibing.


Well this should get you started or other ppl to correct me. Have fun

 

[Lac]

https://computer.howstuffworks.com/hard-disk.htm There you go.

Cheers!
Lac.