There are a lot of advantages to magneto-optical disks, especially when compared to floppy disks. Pen | fun | pavilion www. ｂｉｑｕｇｅ。 infoHowever, if compared with the hard disk that came from behind, there are many shortcomings, otherwise it would not have been popularized among individual users in the previous life.

First of all, the price of its optical drive was high in the initial stage, at least above $1,000, and when the price was reduced to less than $1,000, the hard disk entered the personal computer market under the leadership of IBM and other manufacturers. Secondly, magneto-optical discs are not universal, and cannot be used with CD players who entered the market a few years before him.

The laser head of the CD player is to project the laser onto the mirror and pit of the disc, and use the photodetector to detect the intensity of the reflected laser and identify the '0' and '1' of the data signal burned in the disc.

And what about magneto-optical discs?

Although it also projects a laser onto an optical disc, the reading of the data is done by using a low-power laser to probe the surface of the platter, and by analyzing whether the polarization plane of the reflected polarized light is clockwise or counterclockwise (i.e., the Kerr effect caused by the interaction between the magnetic domain and the laser) to determine whether the data to be read is '1' or '0'.

Therefore, the biggest difference between the two reading methods lies in the optical components in the laser head assembly. Since the optical components are all different, then there is certainly no universality.

Otherwise, another form of magneto-optical disc developed by Sony in 92 years ago, the MD player, would not have become popular not only in Japan, but also among music enthusiasts outside of Japan.

Therefore, Ye Kai's idea is that magnetic optical discs can only be used as transitional products before the popularization of hard disks, and since they are transitional products, they naturally don't need to invest too much. Of course, this does not require too much investment, for Ye Kai, who has the memory of his previous life, it means that he has put aside the cost of research and development.

When a new product is just launched, the reason why the price remains high is because the manufacturer adds the huge R&D expenses in the early stage to the price of the product. It is even more unimaginable for the R&D cost of high-tech new materials such as magneto-optical discs, especially magneto-optical discs that have been developed for nearly 10 years to produce results.

Philips, Sony, Hitachi, Fujitsu and other companies that have invested heavily in the research and development of magneto-optical discs have just put magneto-optical discs into the market, and IBM's personal computer hard disks have also produced results.

Moreover, in this matter, Ye Kai can even dig a pit for those Japanese companies. Because, as the simplest installation of the first generation of Windows operating system and office software magnetic disc, the capacity is about 2M. Then, let those companies see the hope of replacing floppy disks and hard disks, and seize the time to develop magneto-optical discs with larger capacities.

At the same time, Ye Kai is also ready to take a hand in the CD industry. Because, Ye Kai knows that Philips is developing a CD player with Sony, the size of the disc is 12 cm, the capacity is about 650M, and it can play 74 minutes of music.

Therefore, Ye Kai prepared to develop a compact disc with a size of 8 cm and a capacity of 230M to compete with the Japanese. Moreover, the player that plays this kind of disc, Ye Kai is also ready to make a portable music player. You know, Sony launched a portable CD player the following year because of the sluggish sales of desktop CD players, which was a great success.

The reason why Ye Kai wants to avoid Sony's CD disc size is not purely to dig a hole for the sake of digging a hole, but to get a share of the mobile hard disk market in the decline era after the popularity of DVD discs in the future.

Why?

In 1988, Sony invented the first CD Walkman to play a small 8-centimeter disc, but it was abandoned because the capacity was only 230M, which was too small compared to the capacity of a 12-centimeter disc. But no one thought that in less than 10 years, with the development of optical storage technology, the standard of DVD appeared.

After the advent of the DVD standard, due to the popularization of computers, more formats were available, and the capacity of 8 cm discs increased day by day. The capacity of the 8 cm DVD-5 format disc is 1.4G, the DVD-9 format disc is 2.6G, the DVD-10 format disc is 2.8G, and the DVD-18 format disc is 5.1G.

So, imagine how many music formats such as MP3, APE, FLAC, WAV, etc., stored in an 8cm DVD can be played by a fully compatible 8cm small disc portable player?

According to the previous life to buy an 8G SD card 30 yuan to calculate, then you can buy 30 rewritable 1.4G 8 cm DVD small discs, the total capacity is 42G, calculate how many lossless format high-fidelity audio files can be saved? About 1,500 songs. If you buy DVD-18 discs, 30 small 8cm discs can store nearly 6,000 CDs.

What's more, there are more than N video format software, a high-definition movie is compressed into high-definition MP4 format, the capacity is about 5-600M, a D-5 format disc can easily handle two movies, and so on.

All of the above are economical and affordable ways to use, all of which are achieved through this small square flat box with a size of nearly 9 centimeters, except that there is no portable hard disk in terms of copying data, and the others are better than hard disk players, especially MP3 players that replace CD Walkmans.

And Ye Kai wants to compete with Sony in the player business, so in addition to portability and price, the most important thing is sound quality. The MP3 compression method is to compress the CD music according to the ratio of 1:10, so many details in the music are lost, and there is no sense of delicacy, thoroughness and liveness of CD music.

However, when Ye Kai decided to convert the analog sound source to a data sound source, he set the sampling frequency to the limit of 48KB for the human ear and quantified the sample value with 24 bits. In this case, the sound restored by the CD player is not much different from the sound of the scene.

After Ye Kai's calculations,A song is counted as 4 minutes long,If the sampling frequency is set to48KB,Then the amount of data per second of CD is156KB,4 minutes will require 37M,Then the 230M small disc can only store 6 songs,If you compress the data in the way of MP3,Compress the data in a ratio of 1:0.5,Then a 4-minute music only needs 19M,The small disc can also store about 12 songs。

After compression, although there is a loss of the original digital sound source, it will definitely not be lower than the sound quality of a 12cm CD, and it should be absolutely competitive in the market.

This is a typical lack of quantity, all depends on quality!