Disk is a medium used for storing data.
The base of hard disk is made up of firm and durable materials.
The magnetic powders are divided into several concentric circles (which are called tracks).
There are numerous magnets placed randomly on the track of each concentric circle.
The magnets represent the status of 0 and 1.
When they affected by magnetism from the head, the array direction will be changed as well.
Name: disk
Catalog
1.
Structure characters of hard disk
2.
Material of disk
Material of Al alloy substrate
Material of glass substrate
3.
The amount of disks
4.
The surface energy and roughness will affect the growth of buffer layer.
So, the performance of magnetic layer can be optimized and improved by processing the substrate surface precisely.
This requires disks should be possessed of high quality of surface hardness and impact resistance.
Therefore, the chosen substrate must have certain mechanical strength and surface hardness.
The high-speed rotating of disk does help to read and write data quickly.
Whats more, the amplitude will increase with the increase of speed of spindle.
Then, the force which disk suffers will be greater.
Material of A1 alloy substrate Most disks are made of A1 alloy substrate.
After A1 alloy annealing, the hardness is only 0.9GPa and the elastic modulus is only 70GPa.
But NiP layers uneven surface structure makes the flying height of magnet head unable to drop too low.
If the wave height exceeds a certain degree, the magnetic head will no longer move with the waviness.
It will collide with the surface of the disk substrate, and so-called head crush occurs.
It can result in failure of disk gear and error in reading and writing information.
As a homogeneous dense and non-metallic material, glass is firstly chosen as the candidate of Nip/A1 substrate.
Glass-ceramic is considered as substrate of a hard disk to improve the defect of glass substrate.
Glass-ceramic has excellent surface properties, mechanical properties, thermal stability and chemical stability.
Moreover, its strength and toughness are better than glass.
This enables it to meet the requirements of different environments.
The amount of disks
There will be multiple disks in one hard disk.
Every disk has two sides and each side has its own read-write Head (H).
Limited by hard disk size and production cost, the number of disks will be limited within 5.
The number of disk is started with 0 from the bottom up.
The capacity of disks
The capacity refers to the capacity of each single disk, shorted by disk capacity.
Hard disk is composed of plurality of disks, and the disk capacity is the maximum of disk storage.
Manufacturers can enlarge the capacity by two means.
One is to increase the number of disks; the other is to increase the capacity of each disk.
The increase of disk capacity means manufactures should create more tracks.
In addition, the increase of disk capacity can save cost to some extent.
The increase of disk capacity is promoted gradually with the advancement of hard disk technology.
Users now can spend much less money buying a large capacity drive these days.
However, with the increasing of hard disk capacity, more and more disk issues arise.
Some users find their3TB hard drive only uses 2TB, some report that their3TB Drive Only Shows 746GB.
Luckily, MiniTool offers the best solutions here.
