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

The working principle of a hard disk is actually no essential difference from a recorder. It is both on a carrier coated with magnetic paint. The magnetic head discharge is used to change the arrangement direction of the magnetic paint to record information. 1. Reading a book ww?w?·1?·cc is just that the carrier used by the recorder is strip-shaped, and the information volume is larger, requiring a faster reading and positioning degree, a disk is used as a magnetic carrier.

The earliest hard drives appeared in 1956.

Limited to the shortcomings of materials, processing technology, electronic technology level, and pneumatic theory, this hard disk is extremely huge. It consists of fifty steel sheets with a diameter of 600 mm. Each steel sheet is coated with magnetic substances, and then the fifty disks are stacked together from the center. Each layer of disks has a separate magnetic head to read and write data.

Such a huge institution has only 5 trillion reserves!

After decades of research, researchers finally designed a mature hard disk, which is the famous Winchester hard disk system in later generations. It includes a sealed hard disk shell, a fixed and highly rotating disk, a magnetic head that moves radially from the center of the disk to the outside, and the magnetic head floats above the disk and does not directly contact the disk. This is composed of these technical principles.

Among them, the self-floating technology of magnetic heads, highly smooth disk manufacturing technology, high-precision head technology, and stable, precise positioning and fast response high motors are several major technical difficulties in manufacturing hard disks. Other technologies such as interfaces, data protection, shockproof, data cache, etc. are relatively much easier to implement.

Among these technical difficulties, magnetic heads and motors are the top priority.

Especially the head!

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

Early magnetic heads used ferromagnetic substances, which had poor reliability and low data storage limit. A five-point two-five-inch hard disk containing three to five disks had a total storage capacity of less than five megabytes. Although the volume was reduced by several hundred times compared to the initial version, the storage limit was not increased.

It was not until 1979 that ibm developed a thin film magnetic head, and the reading and writing gap was reduced to a slightly thicker than the head wire, and the total storage volume of hard disk was increased. It was only in the eighties that the actual storage limit of hard disks was only 20 trillion, and the selling price was as high as tens of thousands of dollars. Even a wealthy research institution did not have the financial resources to buy in large quantities, and it could only be used as a calculation center to save data, and buy in small quantities!

Anyway, it’s your own use, Guan Fei doesn’t have the patience to follow foreign technology and improve it bit by bit.

According to the manufacturing drawings he provided, the assembly line directly skipped the thin film head, and the mr head was produced.

However, he did not go crazy and took out a large-capacity hard disk with storage capacity measured in g or even t. Instead, he chose the amr anisotropic magnetoresistive technology, writing with thin film heads and reading with strip-shaped magnetic material to increase the capacity of the hard disk.

Under this technology, the magnetic head reads data by inducing changes in the magnetic field of the disk, so it has extremely high sensitivity.

Moreover, because the data is written, the thin-film head is used, so the technology is difficult to implement. On the contrary, the new reading circuit uses fewer components and is easier to manufacture, and the processing cost is lower than that of the original thin-film head. Based on the depreciation of the production line made by the site and the wages of workers, the cost price of a single hard disk is only one or two hundred yuan, which can be said to be cheap and good.

The most difficult magnetic head is not a problem. Disk manufacturing, magnetic coatings, interfaces, data protection, etc. are not only easy to solve, but also have performances far from other products of the same type in the same period.

Through improvements, he can easily take out a 100-megabit hard drive.

In the early stage, he asked him to start production from 80 megabit hard drives, and then gradually improve after the quality control reaches a certain level, producing 100 megabit, 150 megabit, 200 megabit series of hard drives.

The 80-megapixel hard drive alone is already three times higher than the capacity of the hard drives available on the market, and the single megapixel data storage cost has been reduced to two yuan. Compared with the retail price of ibm's 20-megapixel hard drives of tens of thousands of dollars, the unit storage cost has been reduced by more than twenty times!

Guan Fei stayed in the hard disk factory for two days and answered the questions of the factory technicians on the problems encountered in production. He also put forward some suggestions for improvement on the operation process and precautions in production. These opinions are simulated by biological sub-brain, which can greatly improve production capacity, production quality, and control yield rates. Initial training for workers, although they are not yet proficient, the actual production efficiency has been significantly improved.

Finally, he brought the first batch of 500 80-megabit hard drives produced in the factory and returned home with a full load. Then he rushed to the next factory optical fiber factory without stopping. He wanted to read? Book·1 book k?a?nshu·cc

...

The birth of optical fiber was derived from an experiment in the second half of the 19th century.

As we all know, light will not turn, it will only move along a straight line, and as it diffuses, the number of photons gradually decreases and eventually disappears into other background clutter.

But in an experiment in 1870, British scientist Tindal did an interesting experiment while giving a speech on light reflection at the Royal Society. He asked someone to drill a hole in the side wall of a wooden barrel filled with water and then illuminate the bucket with light.

People were surprised to find that the light was actually wrapped in a curved column of water, which did not diffuse, but was twisted, and light came out of the ground with the flowing water.

Therefore, people realized the light reflection effect, and based on this theory, transparent materials are used as the core, and the outer cover is an opaque shell to create optical fibers, which are used as the medium for laser distortion, so that the laser signal can be transmitted several kilometers, dozens of kilometers, or even hundreds of kilometers away to achieve information exchange.

It seems that the manufacturing of optical fibers is not difficult at all. Any transparent object can be used as the conductive material of optical fibers: quartz, glass fiber, and even plastic.

In actual use, there are only three standards for good or bad fiber: transmission loss, length and fiber diameter!

During long-distance transmission, light will inevitably refract due to folding and steering. The lower the loss, the longer the distance of light energy transmission, the higher the bandwidth, the greater the amount of information it carries, and the fewer relay signal reception and amplification devices required in the middle, the lower the laying cost.

The same is true for length.

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

The fiber diameter is better understood.

In the middle of the optical fiber line, there can be a bundle of optical fibers, or there can be many like ordinary cables. The thinner the diameter, the more optical cables there are in a single optical fiber, the larger the channel volume, the larger the amount of information that can be transmitted instantly, and the number of users that are supported will naturally be more.

With the current technical force, the transmission loss of a single optical fiber is reduced to O.2db per kilometer, which means that a 1oodb optical signal will be completely attenuated for 500 kilometers.

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

As for the diameter of the optical fiber, it is measured by the data transmission amount of a single optical fiber. The current upper limit of optical fiber transmission is 140 megabytes per second.

It can be seen from this that although the fiber loss rate is already practical, the length is still very short, so even as the city information trunk line is still extremely costly. Calculated by the transmission length of 100 kilometers, a total of fifty sets of relay equipment are required, and on average, the laying 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 of millions.

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

If a set of relay equipment is prepared every two kilometers, the relay equipment required for a city fiber network will be hundreds of sets, and the laying cost will be billions!

Such high cost makes even wealthy countries like the United States, Britain and Germany unable to afford full fiber networks and can only be used as main lines. Connecting to various blocks and residential communities still uses traditional cables as home connection lines.

The only ones that can be afforded are those large banks with many branches. Because of their high transmission rate, they use it as the data transmission intermediary of the Atm machine.

Guan Fei provides manufacturing drawings. The production line produced does not take much effort to transmit losses, and only reduces the loss per kilometer to o.15db. Others basically use existing technology and materials, but focus on unit length. With this production line, the drawing length of a single optical fiber reaches fifteen kilometers, and the end welding technology can be used to link multiple optical fibers into long fiber lines of dozens and hundreds of kilometers.

However, in order to reduce the bandwidth loss caused by transmission loss, it is best to maintain the length of a single optical fiber for fifty kilometers.

With such an improvement, the number of relay equipment used for thousands of kilometers of all-fiber networks has been reduced to about twenty sets. Even if the cost of digging roads and burying pipelines is not reduced, the unit laying cost has also been reduced to tens of millions of US dollars. This may still be a considerable expense for developing countries, but for European and American countries, especially Arab countries with rich oil resources in the Middle East, this is simply like not having money!

...

Guan Fei took advantage of the gap between the various research units and the reverse research of the various parts and components, and took two weeks to inspect several key enterprises that he paid attention to, mainly to help the enterprises solve various problems encountered in the production process, help them straighten out the production process, improve production capacity, and improve yield.

During this period, a series of key projects such as hard disks, optical fibers, program control equipment chips, laser diodes, optical amplification equipment, etc. have achieved gratifying results.

Everything is ready, only the east wind is not available.

...

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

Among them, the Ministry of Administration and Party Committee Headquarters are located in Section 3 of Renmin Avenue, facing the mountains to the west, facing the commercial area to the east, close to Xincheng First People's Hospital, and on the north is the research area.

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

The most important military command is still in the old military camp, which is a hilly area about ten kilometers away from Longkang Town.

Most of the regular troops went to Xingwei, Guogen, Gunong, Qingshuihe, Guijiao, Mujie and other places to garrison. Among them, the Xingwei front-line defense system troops facing the Wei Ding Army were the largest, with a total of six brigades deployed in stairs, with a width of fifty kilometers and a depth of sixty kilometers.

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

There are only two brigades in the headquarters.

Other domestic veterans, prisoners, and troops to be reorganized were placed in the middle mountainous area, in the Tamengye area, and used them as training bases, and were reorganized and trained while protecting the future military bases.

Guan Fei’s private research institute is located in the valley behind the military command. Engineers have begun to dig up the mountain walls. In the future, some laboratories will further hide in the belly of the mountain, and safety and confidentiality will be further improved.
Chapter completed!