There are very delicate parts inside the mechanical hard disk, but do you know how precise they are? The distance between the head and the platter during operation is within 0.3 μm. If you think this value is not easy to understand, the PM2.5 value refers to particles with a diameter of less than or equal to 2.5 μm. It is conceivable that in this precise environment, a small dust will cause damage to the platter, so many people say that the inside of the mechanical hard disk is vacuum. This statement is actually wrong, the current mechanical hard disk has two main packages, the internal is air and helium.
Air discs have a low cost of opening holes
Our most common hard disk is non-airtight, the internal space is filled with air, in order to avoid the impact of temperature changes, the inside and outside of the hard disk are connected through a small hole, we can find this small hole on the side of the label, next to which there will be a word prohibiting coverage. But this small hole is not a simple opening hole, it will have a dense film inside, which can allow air to flow and block dust, ensuring a dust-free environment inside the hard disk. The advantage of such a hard disk practice is that the cost is low, as long as the hard disk is assembled in a dust-free environment, it can be used without vacuum, and the long-term use of the hard disk can be guaranteed.
Helium disc has strong non-opening performance
The positioning of high-end hard disks will be another way, that is, the use of a sealed structure, the interior is filled with helium. Because helium is an inert gas, it is not easy to chemically react and is more stable, and it does not have to worry about damage to internal components and data for a long time. In addition, the density of helium is only 1/7 of that of air, so the resistance of the platter and the head will be much smaller when working, which can not only make the head closer to the platter, but also make the track more dense, increase the capacity of the platter, and make the noise lower.
Helium disc because of the higher cost, generally used in 10T level large-capacity products or enterprise-class hard disks, because the full disk is sealed, so there is better performance in durability, but the price will be more expensive. The way to distinguish between the air plate and the helium plate is very simple, the air disk has a small hole in the air plate, which is assembled with screws; while the helium disk does not have a small hole, nor does it use screws but is directly welded.
It should be reminded that although the storage density of helium disks is higher and more stable, it is not necessary to blindly pursue helium hard disks when purchasing, because helium hard disks are more expensive and have a larger starting capacity, so users who do not have special needs can choose CMR hard disks.