Pi is a magical thing, this thing is endless, never the last digit, when Zu Chongzhi calculated to the first decimal place, in fact, it was enough, until modern times, after the invention of electronic computers, many restless people began to use computers to calculate pi. Without him, I just think it's fun.

Eniac, the world's first computer, once calculated 2037 bits in 70 hours, five years later IBM NORC calculated 3089 bits in 13 minutes, and in 1973, the supercomputing CDC 7600 calculated this number to 1 million bits for the first time, which was nearly an hour at that time.

Of course, this is also due to the size of the computer's computing speed, if you use the lowest i3 processor in the later generation to calculate, the same million bits, only 11 seconds is enough!

In '89, the world's most advanced supercomputer, Cray-2, pushed the calculated value to 480 million for the first time, and in later generations, it reached a maximum of 3.14 billion bits.

Although it is said that calculating pi is purely idle, however, the length of pi calculation time directly reflects whether a computer performance is advanced, so, for a long time, calculating pi is a tool used to measure computer ability, and the University of Tokyo in the island country has come up with a special super pi software to detect the performance of the processor, which is the same as the later generations using Master Lu to run the score.

Loongson No. 1 was born, and the strength of the performance can be demonstrated by calculating the pi of one million bits, so that the world can see how powerful the processor developed by Dongfang is!

It's just that if Qin Feng directly sends someone to shout the slogan, it is estimated that no one will listen to it, and he will be driven away by the security guards, and if he distributes leaflets, the publicity effect will not be good, and now, the drone flew overhead and immediately attracted everyone's attention.

"Hey, what kind of flying machine is that? A helicopter with four propellers? ”

"That thing can only fly up and down, right? It's okay indoors, but outdoors, if you get a crosswind, it's probably going to blow down! ”

In the midst of the audience's discussion, the reporters reacted, raised the cameras in their hands, and pressed the shutter on the thing.

Click, click!

The organizer of the Hannover Messe is Hannover Messe, and the head of the company, Matthaus, happened to be here, and at this time in front of the booth of the famous German electronics company Siemens, he chatted with Oliver, a sales representative from Siemens.

A buzzing sound rang out, and both of them looked up.

"Matthaus, you've also arranged a flying machine show?" Oliver asked curiously.

"Nope." Matthaus shook his head: "It wasn't arranged by us, it may be from a certain manufacturer, knowing that it is difficult to see advertisements on the ground, so he actually flew into the sky to advertise, but ...... There is no prohibition in the regulations. ”

When the exhibition hall is rented, it is according to the area, and it does not say how high the booth is arranged, so if the manufacturer has a plan, it can be developed overhead, but it is generally to hang a balloon or something, and hang a banner under the balloon.

At this time, Mateus only thought that this thing was a vertical lift, similar to a balloon, after all, how could such a flat aircraft fly forward.

Just when everyone thought that this thing was similar to a balloon, its voice suddenly changed, probably the speed of one of the rotors, and then, the attitude of the entire aircraft changed, and it suddenly moved in the direction of the gate of the exhibition hall!

"How is this possible, how can it fly sideways!"

"yes, this, this is definitely the world's first multirotor rotor!"

All were shocked.

Although the world's first quadcopter appeared at the beginning of this century, and it was taken out and studied in the fifties when vertical take-off and landing aircraft were popular, they were not put into use, and even the control of vertical take-off and landing was difficult.

And the one in front of you can not only rise and fall vertically, but also fly horizontally!

Everyone has the feeling of watching science fiction.

"Ladies and gentlemen in front of the TV, the Hannover Messe did not disappoint us, we saw a special shaped aircraft take off at the venue, it has four rotors, it can take off and land vertically, it can hover, and it can fly horizontally, and look, it is flying towards us!"

A reporter excitedly reports to the camera, but before he can finish speaking, the thing has already flown over, so the photographer holds up the camera and the camera is pointed at the aircraft.

That's awesome!

Click, click!

The flash of the camera kept flashing, and almost all the reporters at any booth were attracted by the overhead thing, gave up their previous reports, and concentrated on taking pictures of the overhead.

Even the exhibitors in the booth looked up at that thing at this time.

People with poor eyesight may not be able to see the small drone, but they can see the banner hanging underneath, although the banner is written in English, but many people can recognize it.

What is a Loongson processor?

Pacific Group? How does this feel so familiar...... Some impressions, wait, we seem to have been in a meeting hall before? Finally, someone thought of the previous scene, and suddenly smiled bitterly, this Pacific Group is just going to play all kinds of tricks!

Thanks to the relatively open overhead and the banner, Liu Yang was able to skillfully operate the drone, flew through the densest crowd, flew to the door, and then returned to the ......

Hu Miaomiao's mood was a little nervous, hoping that there would be no malfunction, if there was an accident and the drone fell, the rotor would be like a sharp meat grinder cutter...... Then it's another story, and although they've done countless rehearsals, it's still stressful.

Qin Feng didn't care, and sat comfortably in the chair: "Now it can only be controlled by remote control, but in the future, after the advanced inertial navigation system and satellite positioning are released, it will not be difficult to fly autonomously." ”

"Hmm." Hu Miaomiao nodded: "Mr. Qin, we also think so, and at that time, we will also have a more advanced processor, which will have stronger computing power and easier control." ”

If you want to operate autonomously, whether it is a huge bomber or fighter jet, or a small drone or even a simple sweeping robot, you need to know where you are at all times, then you need to know your own trajectory, which requires an inertial navigation system.

Before the nineties, the inertial navigation system was a big guy of more than a dozen kilograms, and there was a lack of similar technology in China, such as the Peace Model project, which not only had radar, fire control, but also advanced inertial navigation systems, which needed to be imported from the United States.

It was not until the nineties that the inertial navigation system could be reduced to a few grams of weight with the maturity of advanced microelectromechanical systems, that is, MEMS systems, so that it could be regarded as flowering everywhere, and the automatic control system of multi-rotor aircraft was considered to have a foundation.

Now this quadcopter can only be remotely controlled, essentially a model aircraft, but has overcome the most complex multi-rotor nonlinear control system in the UAV, in the past two years, technicians modeling, design control algorithms, implementation of control algorithms, busy, today, finally shown to the world!

As the drones began to return, the flow of people on the ground began to pour into the Pacific Group's booth. If you look at it from the sky, you can see that the security personnel are nervous just like the sea water that gathers into the whirlpool, and if there is a problem with the order, there is a high risk of a serious stampede!

Qin Feng stood up from the chair: "Old Ni, it's finally our turn to play!" ”

The last time I played the Future Warrior system, in the end it was just to sell bulletproof inserts, and this time I played drones, just to show Loongson.

Drones are too advanced to be announced to the public for the time being, so we are just using them as a tool for publicity.

"Mr. Qin, may I ask if the drone above your head belongs to you?" At this moment, there were already reporters crowding up.

Yellow skin, black eyes, and an oriental face at first glance, and the contour of the face seems to have been seen somewhere.

"Ohashi is empty?"

Daqiaokong was immediately flattered: "Mr. Qin, I didn't expect you to remember me, can you accept my interview?" Oops! ”

At this time, there were already more people squeezing over from behind, and Daqiaokong did not stand firmly, and he was knocked into his body and rushed straight into Qin Feng's arms.

Qin Feng was quick to move, swished away, and then threw the chair over.

Almost on the verge of physical contact! Qin Feng secretly sighed in his heart that his movements were agile, this Daqiao Kong teacher couldn't have anything to do with him, he was single-minded.

Who knows if this woman is intentional, what is the motive, or less contact.

Ohashi Sora only felt that his body was out of control, and then he sat down on the chair with a bang, and it hurt a little...... What about Mr. Qin? I didn't even help myself......

Qin Feng had already jumped onto the stage quickly and looked at the people rushing below.

"Everyone, welcome to visit our booth of the Pacific Group, our Loongson company, a subsidiary of the Pacific Group, has just developed an advanced processor, named Loongson No. 1, this processor ......"

"Mr. Qin, is this flying machine yours?" There are already reporters below who can't wait to ask.

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"That's right, it's our company, but this aircraft is only for publicity, we ......"

"Mr. Qin, what is the principle of this flying machine? How can you fly horizontally? ”

"How are the four rotors coordinated?"

These guys are all interested in this flying machine! I don't care about the Loongson processor that Qin Feng said!

Qin Feng was prepared: "Of course, this is because we have a powerful Loongson No. 1 chip built into it!" ”

When developing the chip, Qin Feng wanted to prepare a smart brain for his products, but after all, Loongson No. 1 had just come out, the computer motherboard and the like had just been soldered, and the system was also the most primitive, and it was impossible to use it in other fields.

Whether it's a quadruped robot or a drone, they all use ordinary 386 processors, but as long as they don't take it apart, who knows what chip is inside? Even if it is disassembled, the words on the surface of the chip have long been polished.

"Loongson One?"

"That's right, Loongson No. 1, the biggest feature of our processor is that the main frequency is very high, and the first batch of products launched so far has a frequency of up to 50 megahertz!"

Almost at the time of Qin Feng's introduction, on the other side of the world, Grove was introducing their 20 megahertz 486 processor, boasting that it was the first in the world, and now, Qin Feng has introduced Loongson, with a starting frequency of 50 megahertz, more than 486 one and a half times!

"Fifty megabytes, how is it possible, even if your Loongson processor can run so fast, the motherboard can't support it!" There was a voice of doubt below, this is not an introduction to a group of ordinary people who don't know anything, the manufacturers who came to participate in the exhibition, and the customers who came to purchase are professional!

How fast the processor runs depends on the motherboard, which has a clock circuit that provides a stable frequency for the entire computer system, and all the parts on the motherboard run in sync according to this frequency.

Now the highest frequencies are 25 megahertz and 33 megahertz, and a few extreme overclocking can reach 40 megahertz, even if the processor can run to 50 megahertz, can other parts of the entire circuit board, such as memory, run so fast? Don't you have to be tired and self-immolated?

"yes, it can't be!"

Looking at the questioning gaze below, Qin Feng smiled: "Everyone, our Loongson processor is cross-era, and on this processor, we use frequency doubling technology. ”

"Frequency multiplication? What do you mean? ”

"We know that the processor is going to run faster and faster, but the rest of the computer can't run at the same time, so we came up with the concept of frequency multiplication, and the outside circuit is running at 25 megahertz, and our processor is running at twice the speed, which is 50 megahertz."

Frequency doubling is an important technological breakthrough to solve the contradiction between the internal and external rates of the computer, the outside runs slowly, the inside runs fast, it doesn't matter, as long as it is multiplied, the high-performance processors of later generations are often dozens of times the frequency, the external frequency is 100 megahertz, the processor frequency is high or low, just look at the frequency doubling, the most bullish i9 processor, the frequency can reach 74, so that the frequency reaches 7.5G Hz.

The frequency doubling technology started from the 486 era, but it was not the original 80486dx, but the later 80486dx2, which is the double frequency, followed by dx4, that is, 4 times the frequency, so that the external frequency is still 25 megabytes, but the main frequency has reached 100 megabytes.

However, the processor frequency is high, the heat will increase rapidly, to reduce the heat, it needs a more advanced production process, the processor with frequency doubling will not be available until the 0.8 micron process, and Loongson, relying on the 0.8 micron production process, directly tinkered with the frequency doubling!

Although Loongson has just set foot in the processor market, it has already brought some earth-shattering changes to the entire processor industry, and this frequency doubling technology is one of them!

Intel cry, you haven't yet, we've already figured it out!

"This technology sounds very advanced!"

"Yes, this Loongson processor, is it very powerful?"

"Guys, here, we're going to show the calculation of pi live, as you know, this is a project that supercomputers like to do, today, we're going to show it here, calculate to a million bits, see how much time it takes, first of all, please take a look at the program."

Although it uses the Dragon architecture and the Dragon instruction set, the software of this era is very simple and easy to port, after all, the DoS system commonly used in this era was written by Tim Patterson, a programmer at Seattle Computer Products in the 80s, in four months. The earliest Linux system, it is said to have taken only a month.

Now, you only need to let Loongson No. 1 run, and it doesn't matter what other interruptions and other operations are, as long as you can run the pi calculation program, it won't take long.

A "huge" drawing-specific 21-inch monitor was placed on the booth with a blue interface, typical of the C programming environment, where code appeared on the screen.

Regardless of the infinite number of pi, the program to write it is actually very simple, if you want to calculate to a thousand decimal places, six lines of code are enough.

Now to calculate millions of bits, the number of codes is not very large, experienced programmers can see at a glance that it is the latest square-convergent iterative function method developed by mathematicians in 76, the accuracy of the operation is quite high, and there is no problem in calculating one million bits.

"Okay, now let's look at the time, at half past three in the afternoon, we will start counting on time!"

The program starts running, and the numbers start jumping up and down the screen.

"That's too fast, isn't it?"

"yes, I have a 40 megahertz 386 computer on hand, and I can't do it that fast!"

The numbers are jumping so hard that they can't be seen clearly, indicating that the data is being calculated in a steady stream of time!

It's not a supercomputer, it's just an ordinary microcomputer! The computing power of a personal computer can be stronger than that of a supercomputer more than ten years ago!

This is no joke, the first supercomputer to calculate millions of bits was only 36 million times per second, or 36 megahertz, and now the speed of a personal computer can reach this level!

However, using 386 to calculate pi is not fast, because it relies mainly on floating-point arithmetic!

Time passed little by little, and the people below all looked up at the computer screen, and no one noticed that the drone had quietly landed and then been recovered.

The mission of the drone has ended, and the next one belongs to Loongson!

Ten minutes, twenty minutes...... Half an hour.

"It's now 4:03, and our Loongson No. 1 has completed all the calculations!" Qin Feng said: "If there is a sponsor on the spot, let us print out the results, if not, then we can only display them on the screen, and everyone can take photos to verify whether our calculation results are correct." ”

Computers can also make mistakes, especially defective processors, and now it's not just about being fast, it's also about being accurate!

"We have it at the Phoenix booth, so you can bring it." Someone below shouted, "However, we want to exchange our printer for a piece of your Loongson processor!" ”

"This ...... We're at a loss, but we can ......."

"Suffer? How much does your processor cost? ”

"Now announce the price of our Loongson No. 1 processor, nine hundred and fifty dollars a piece!"

PS: 1000-digit pi program:

#include

long a=10000，b=0，c=2800，d，e，f[2801]，g;

void main()

{

for(; b-c; )

f[b++]=a/5

for(; d=0，g=c*2; c-=14，printf(“%04d“，e+d/a)，e=d%a)

for(b=c; d+=f[b]*a，f[b]=d%——g，d/=g——，——b; d*=b);

}

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