HISTORICALLY, TWO IBM ENGINEERS LEFT NEXT YEAR TO FORM SEAGATE IN SILICON VALLEY, AND A YEAR LATER RELEASED THE FIRST 5.25-INCH HARD DRIVE FOR PERSONAL COMPUTERS. Seagate then became an international corporation with a market capitalization of more than $30 billion.

The investment in chip factories is too large, and it is not suitable for them at present, and there is a lot of investment in CRT factories, but the investment in hard disks is much less, and the money comes very quickly.

Hard disks have two core technologies, one is the read-write head, which accounts for almost half of the cost of hard disks; The other is the platter, which accounts for almost 4% of the cost of the hard disk, and the last percent is the shell material and control circuit and motor of the hard disk.

Disassemble the hard disk one by one, first of all, his shell and control circuit are very easy to solve, especially the circuit components can be bought on the market, there is no need to build a special factory, the shell and circuit are handed over to a Foxconn foundry; Hard disk motors, the hard disk motors of later generations use liquid bearingless motors, which are a bit too advanced for the current time, and can not be used, they can be replaced by other motors, which can be bought on the market, and there is more than one factory business that produces hard disk motors, there are more than a dozen in the world, the United States, Europe, RB, South Korea and even Taiwan have three companies in production, and there is no need to build a motor factory.

The rest is only the magnetic head and platter, as well as the hard disk assembly factory, which Li Yixuan has to consider.

First of all, the core part of the hard disk head, the head of the hard disk is divided into a read head and a write head, in the early days of the development of the hard disk, people usually combine the two heads into one, thinking that it can reduce the size and save space. However, after a long period of practice, it was found that this idea was wrong, so the two types of heads were separated. The 5.23-inch hard disk released by Seagate in 1980 separated the read head from the write head for the first time.

Why separate the two types of heads, because the read head and the write head work differently. The reading head relies on the magnetic sensitivity on the platter to read the data from the hard disk; The write head, on the other hand, relies on electrical induction to write data to the platter.

Forcing two completely different working principles together will naturally increase the difficulty of head design and production costs, and the volume will become extremely large.

Li Yixuan is ready to use the folding thin film induction TFI head technology released by Western Digital in 1990, and the layout of the internal head of the hard disk adopts the head reset energy-saving layout, that is, the two heads are set up oppositely, and the head is set up as an industrial robotic arm, with an axis in the middle, which can rotate the head.

When working, the head turns to the platter, and when it is not working, it turns over, which can not only minimize the damage of the hard disk, but also reduce the power consumption when the head is not working and idle.

Li Yixuan picked up the pen and drew a simple sketch of the reset head structure in Zhang Guifang's office.

The most critical head is solved, and then the platter.

To make a platter, we must first determine the material selection of the disk base, and the hard disk platter is made of durable and durable materials for the disk base, on which magnetic materials are attached, and the surface is processed quite smooth. Because the platter rotates at high speed inside the hard disk (5400 rpm, 7200 rpm, 10000 rpm, or even 15000 rpm), the hardness and wear resistance of the material used to make the platter are very high, and alloy materials are generally used, most of which are aluminum alloys.

Hard disk platters are constantly improving with the development of hard disks, and the early hard disk platters used plastic materials as the disk base, and then coated with magnetic materials on the plastic disk base to form the hard disk platter. Later, with the increase of hard disk speed and capacity, the metal disc base appeared, and the metal disc base has a higher record density, stronger hardness, and is stronger than the plastic disc base in terms of safety.

In later generations, our common mechanical hard disks were made of aluminum metal disks. However, there is also a capacity limit for the metal disk base, and the upper limit is 2TB capacity.

In 2016, the capacity of the aluminum alloy disk base was basically developed to the extreme, if you want to increase the storage capacity of the hard disk without replacing the disk base material, the only way is to increase the number of platters in the hard disk, but this not only increases the volume of the hard disk, but also greatly increases the cost of the hard disk.

As a result, people began to look for new disc base materials with larger capacity and space.

In fact, as early as the early 90s, scientists began to look for a new type of plate base material to replace the aluminum alloy plate base, IBM discovered quartz glass, they found that the base made of quartz glass, the base capacity is 100 times higher than the aluminum alloy plate base, and in the later stage of development, the capacity can be about 5000 times higher than the aluminum alloy.

In addition, they also found that the glass disc is a more durable and durable disc material than aluminum, the stability and reliability of the disc are improved when running at high speeds, and the surface of the glass disc is smoother, and more importantly, the production cost of the glass disc is much lower than that of the aluminum alloy disc.

Because, to make aluminum alloy discs, it is necessary to build a large-scale aluminum alloy smelting plant first, and it involves a complex alloy smelting process, and the upfront cost investment is not generally high. On the contrary, the glass disc base does not have this problem.

In 1998, IBM released the world's first quartz glass hard disk, which shook the world. But soon the glass hard drive was ruthlessly eliminated by the market.

The reason is that quartz glass is silica, a material that has a fatal drawback and is very fragile.

In any case, it was also realized that glass discs were still technologically ahead of metal discs.

As a result, people began to try to replace quartz glass with other glass materials. They first tried to use tempered glass and plexiglass, and found that it was not easy to break, but the storage capacity was only up to 20GB, which obviously could not replace the aluminum alloy platter.

So I started to look for the rest of the glass materials, and in the process of searching, people also tried all glass materials, including bulletproof glass, car windshields, plexiglas on the cockpit canopy of fighter jets, and even the multi-layer composite glass on the cockpit canopy of the F-22, but either the cost was too high, or the storage capacity was too low or fragile.

After years of searching, I finally found a satisfactory glass material, that is, the inorganic tempered glass-ceramic discovered by accident in the laboratory of Corning Company in the United States in 2014, this glass not only has the large storage capacity of quartz glass, the surface hardness of glass-ceramic is higher than that of quartz, which shows that it is more durable than quartz, because the internal molecular arrangement is a crystalline structure, very close to the arrangement of diamonds, therefore, the solidity of glass-ceramic is comparable to bulletproof glass; In addition, his production cost is also much lower than that of aluminum alloy discs, only one-third.

As a result, glass-ceramic has become the most ideal disk base material for mechanical hard disks in the future.

However, the production of glass-ceramic has high requirements for process technology, and it is not yet possible to produce it on a large scale, because the process is not mature, and the yield rate is also low, which leads to the production cost of glass-ceramic can not be reduced.

In addition, there is another technical problem that plagues the popularization of glass-ceramic hard drives, that is, the traditional magnetic material can not be firmly attached to the glass surface, and after a period of use, the magnetic material on it will fall off, thus losing the storage function.

This necessitates the development and search of new magnetic materials, but this brings a new problem, the previous head cannot be used, and the new head technology must be used, and the new head technology will bring a new problem, and the format of the hard disk will also change.

This change will bring a problem, that is, the data stored in the traditional hard disk, can not be directly copied on the glass-ceramic hard disk, the data needs to be converted before it can be copied, which brings an increase in cost.

These technical challenges will not be solved in the short term, and scientists have predicted that glass hard drives will not be on the market until 2025, let alone become widespread.

With the current level of computer technology, whether it is an aluminum alloy disc or a glass-ceramic disc, it is too sci-fi.

Not to mention the big investment, today's personal computers don't need such extravagant materials. Even if you want to use it, other technologies won't hold up.

Therefore, Li Yixuan can only make a choice in plastic materials.

Seagate's hard disk launched in 1980 is made of floppy disk-like materials. The capacity of this material is too low, and the cost is also high, so it is not suitable, and Li Yixuan was shot directly.

He picked up a document and looked at it carefully, which recorded that people had experimented with those materials in order to obtain more hard disk storage capacity.

Finally, we finally found a composite plate base material for the current and next 10 years - polycarbonate (PC).