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And these 3.5-inch aluminum alloy discs are the storage substrates of mechanical hard disks!

The working principle of the hard disk, in fact, is not fundamentally different from the tape recorder, which is on a carrier coated with magnetic paint, and the magnetic head discharge is used to change the direction of the arrangement of the magnetic paint to record information. Pen "Fun" Pavilion www.biquge.info one? Reading ww?w?· 1?· CC is just that the carrier used in the tape recorder and video recorder is ribbon, and the hard disk with a larger amount of information and faster reading and positioning is used as a magnetic carrier.

The first hard disk appeared in 1956.

Limited to the lack of materials, processing technology, electronic technology, and aerodynamic theory, this hard disk is extremely large, and it is composed of 50 pieces of steel with a diameter of 600 millimeters. Each steel plate is coated with a magnetic substance, and then the fifty platters are stacked on top of each other from the center, and each platter has a separate head to read and write the data.

Such a huge institution, but the reserves are only five trillion!

After decades of research, researchers finally designed a mature hard disk, which is the famous Winchester hard disk system, which includes a sealed hard disk shell, fixed and highly rotating platter, and a magnetic head that moves radially outward from the center of the platter, and the magnetic head floats above the platter, and does not directly contact the platter.

Among them, the self-floating technology of the magnetic head, the platter manufacturing technology with a highly smooth surface, the high-precision magnetic head technology, and the high motor with stable and accurate positioning and fast response are the main technical difficulties in the manufacture of hard disks. Other technologies, such as interfaces, data protection, shock protection, data caching, etc., are much easier to implement.

Among these technical difficulties, the magnetic head and motor are the top priorities.

Especially the heads!

The width of the gap between the head reading disk information determines how much data a disk can store. The sensitivity of the magnetic head determines the reliability of reading information.

The early magnetic head was made of ferromagnetic material, which had poor reliability and low data storage limit, and a large 5.25-inch hard disk containing three to five disks had a total storage of less than five megabytes. Although it is hundreds of times smaller than the initial version, the storage limit has not been increased.

It wasn't until '79 that IBM developed a thin-film head, and the read/write gap was reduced to a slightly thicker than the headwire, and the total storage of the hard disk was increased. A look at the book ww?w?· However, until 81 years, the actual usable hard disk storage limit has only reached 20 megabytes, and the price is as high as tens of thousands of dollars.

Anyway, it's for his own use, Guan Fei doesn't have the patience to follow the trend of foreign technology and improve little by little.

According to the manufacturing drawings provided by him, the assembly line directly skipped the thin-film head, and the MR head was produced.

However, he didn't go crazy enough to take out a large-capacity hard disk with a storage capacity of G, or even T, but chose AMR anisotropic reluctance technology, which increased the capacity of the hard disk by writing with a thin film head and reading with strip-like magnetic materials.

In this technique, the head reads data by sensing changes in the magnetic field of the disk, making it extremely sensitive.

In addition, since the data is written using a thin-film head, the technical implementation is very difficult. Instead, it is a new readout circuit that uses fewer components, is easier to manufacture, and is less expensive to manufacture than the original thin-film head. Based on the depreciation of the production line and the wages of workers, the cost of a single hard drive is only one or two hundred yuan, which can be described as cheap and good.

The most difficult magnetic head is not a problem, and there is no difficulty in disc manufacturing, magnetic coatings, interfaces, data protection, etc., not only are they easy to solve, but also the performance is far from other products of the same type at the same time.

With the improvements, he can easily come up with a 100-megabit hard drive.

In the early days, as a practitioner, he asked to start the production of 80 megabyte hard disks, and then gradually improve after the quality control reached a certain level, producing 100 megabytes, 150 megabytes, 200 megabytes and other series of hard disks.

The 80 megabyte hard disk alone is three times higher than the hard disk capacity available on the market today, and the cost of single trillion data storage has been reduced to two yuan. Compared with the retail price of tens of thousands of dollars for IBM's 20 trillion hard drives, the unit storage cost has been reduced by more than 20 times!

Guan Fei stayed in the hard disk factory for two days, answered the questions of the factory technicians on the problems encountered in production, and put forward some suggestions for improvement on the operation process and precautions in production. These opinions are the key links that can greatly improve production capacity, production quality, and control yield rate through biological auxiliary brain simulation, and the initial training of workers is not yet proficient, but the actual production efficiency has been significantly improved.

In the end, he took the first batch of 500 80 hard drives produced in the factory, returned with a full load, and then rushed to the next factory - the optical fiber factory. Want? See?? Book 1 Book K?a?

……

The birth of optical fiber originated from an experiment in the second half of the nineteenth century.

As we all know, light does not bend, it only travels in a straight line, gradually decreasing the number of photons as it spreads, and eventually disappears into other background clutter.

But in 1870, the British scientist Tyndall gave a lecture on light reflection at the Royal Society, and did an interesting experiment. He had a hole drilled in the side wall of a barrel filled with water, and then illuminated the bucket with light.

People were amazed to see that the light was wrapped in a curved column of water, and instead of diffusing it, it was distorted and emitted with the flowing water.

As a result, people have realized the light reflection effect, and based on this theory, optical fibers are manufactured with transparent materials as the core and opaque shells wrapped around the outside, which can be used as the medium for laser distortion transmission, so that the laser signal can be transmitted to several kilometers, tens of kilometers, or even hundreds of kilometers away to achieve information exchange.

It seems that the manufacture of optical fibers is not difficult at all, as long as it is transparent, it can be used as a conductive material for optical fibers: quartz, fiberglass, and even plastic.

But in practice, there are only three criteria for whether an optical fiber is good or bad: transmission loss, length, and fiber diameter!

The lower the loss, the farther the distance of light energy transmission, the higher the bandwidth, the greater the amount of information carried, and the less relay signal reception and amplification device required in the middle, the lower the laying cost.

The same goes for length.

The longer the length of a single fiber, the less intermediate equipment is needed, and the lower the cost.

The fiber diameter is better understood.

In the middle of the optical fiber line, it can be bundled with one optical fiber, or it can have many like ordinary cables. The finer the diameter, the greater the number of optical cables in a single optical fiber, the larger the number of channels, the greater the amount of information that can be transmitted instantly, and the greater the number of simultaneous communication users supported.

With the current state of technology, the transmission loss of a single fiber is reduced to o per kilometer. 2dB, which means that an optical signal will be completely attenuated after 500 kilometers of transmission.

The manufacturing length of a single fiber is two to three kilometers.

As for the diameter of the optical fiber, it is measured by the amount of data transmitted by a single optical fiber, and the upper limit of fiber transmission is now 140 megabits per second.

It can be seen that although the loss rate of optical fiber is practical enough, it is still very short in length, so it is still extremely expensive even as an urban information trunk. Based on the transmission length of 100 kilometers, a total of 50 sets of relay equipment are required, and the average cost per kilometer is as high as 5 million US dollars.

Even in China, where labor costs are low, the unit cost of relay equipment is as high as tens or millions.

You must know that the cable laying in a city is often calculated in thousands of kilometers!

If a set of relay equipment is prepared every two kilometers, hundreds of sets of relay equipment are required for an urban optical fiber network, and the cost of laying is billions!

Such a high cost makes even rich countries such as the United States, Britain and Germany unable to afford all-fiber networks and can only be used as backbone lines. It is connected to various blocks and residential areas, and the traditional cable is still used as the connection line to the house.

The only ones that can afford it are the big banks with many branches, because of the high transmission rate, as the data transmission intermediary of the ATM.

Guan Fei provided manufacturing drawings and produced this production line, which did not put too much effort into the transmission loss, but only reduced the loss per kilometer to O. 15db, the other basic use of prior technology, materials, and focus on the unit length. With this production line, the drawing length of a single fiber reaches 15 kilometers, and the end fusion technology can be used to link multiple sections of fiber into tens or hundreds of kilometers of long fiber lines.

However, in order to reduce the bandwidth loss caused by transmission loss, the length of a single fiber is still 50 kilometers.

With such an improvement, the number of relay equipment used in the 1,000-kilometer all-fiber network has been reduced to about 20 sets. Even if the cost of digging roads and burying pipelines is not reduced, the unit laying cost has also dropped to tens of millions of US dollars, which may still be a lot of money for the developing countries, but for countries such as Europe and the United States, especially the Arab countries rich in oil resources in the Middle East, this is simply the same as not asking for money!

……

Guan Fei took advantage of the fact that various research units were still conducting reverse research on various parts and components, and took two weeks to inspect several key enterprises, mainly to help enterprises solve various problems encountered in the production process, help them straighten out the production process, improve production capacity, and improve yield.

During this time, hard disks, optical fibers, program-controlled equipment chips, laser diodes, optical amplification equipment, ...... and a series of other key projects, which have achieved gratifying results.

Everything is ready, only the east wind is owed.

……

The Northern Theater Command is divided into three parts: the Military Command Department, the Administration Department, and the Party Committee.

Among them, the Administration Department and the Party Committee Headquarters are located in Section 3 of Renmin Avenue, with the west facing away from the mountain, the east facing the commercial district, close to the First People's Hospital of the new city, and the research area on the north side.

The two headquarters each have an office building group, and there are two ** entrances and exits on the outside, but they are connected on the inside and are not separated.

The most important military command department is still in the location of the old military camp, that is, the hilly area about ten kilometers away from Longkang Town.

Most of the regular troops went to Xingwei, Guogen, Rolling Lane, Qingshuihe, Guiji, Mujie and other places to garrison. Among them, the Xingwei front-line defense system facing the Weiding Army had the largest number of troops, with a total of six brigades, spread out in echelons, and the defensive front was 50 kilometers wide and 60 kilometers deep.

Facing the direction of the Wa mountainous area, where the Central Committee of the People's Party is located, four brigades were also released.

Headquarters here there are only two brigades.

Other domestic veterans, prisoners, and units to be reorganized are placed in the mountainous area in the middle, in the area of Tamengye, as a training base, and train while reorganized, and by the way, protect the future military industrial base.

Guan Fei's private research institute is located in the valley behind the military command department, and the engineers have begun to dig on the mountain wall, and in the future, some laboratories will be further hidden in the belly of the mountain, and the security and confidentiality will be raised to a higher level.

And today, under the leadership of Guan Fei, a very important project is being carried out here.

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