Chapter 639 I'll Take the Lead on This

Oh, that makes sense. If the data is accessed across the entire disk, then this protection cannot be implemented. Chief Engineer Gao has even considered such details in advance.

It seems that the legend that he not only has profound theoretical knowledge, but also has extremely rich practical application experience and is thoughtful and considerate is indeed true.

Seeing that everyone had a clear idea of ​​this, Gao Zhendong said, "Let me talk about my design of the disk storage structure. First of all, the storage disk and the reading mechanism of this storage device are separated, just like a magnetic tape."

Gao Zhendong also considered the problem of hard disks, but if you think about it carefully, before the giant magnetoresistive head, the storage density of hard disks could not be increased. Even if it was equipped with a sealed disk body, rigid platters, and high-speed rotation, the most core demand of this era - storage density - was not far from that of open disks. There was no essential difference, and the capacity could only be increased by stacking the number of platters.

In this way, the significance of the hard disk is not very prominent for the time being.

Nowadays, computers themselves are not fast, and the main contradiction between storage devices and computer performance is capacity. With limited resources, Gao Zhendong had to focus on the main contradiction.

In addition, another major contradiction is cost. In this regard, open removable disks are much better than closed disks. The cost of the reading mechanism is one-time. To increase capacity, you only need to produce disks, which is very cheap. Every penny is spent on capacity expansion.

Gao Zhendong plans to put aside the hard disk, or external storage devices with large capacity, high density and high speed for the time being.

No one had any objection to Gao Zhendong's idea. In this regard, there was no one in the world who could think more comprehensively than him.

Seeing that no one had any objection, Gao Zhendong drew a disk diagram on the blackboard.

"I've already talked about the basic structure of the disk. For the disk itself, I'm considering using flexible materials, that is, plastic. The inner hole has a diameter of 2.5 cm, and the outer ring has a certain amount of redundancy when actually reading. The non-data storage area of ​​the inner and outer rings occupies a total diameter of 3 cm, leaving a 6 cm wide ring for storing data."

Gao Zhendong spoke very clearly, with the help of the diagram on the blackboard, and no one interrupted him because they understood him very well.

"I plan to divide these 6cm into 20 circles, or 20 magnetic tracks..." Gao Zhendong drew some circles in the ring on the picture.

"Each track is divided into 9 sectors..." He used line segments to divide one of the circles into many segments.

"Each sector is 512 bytes..." He enclosed one of the sections in large curly brackets and wrote "512Byte".

Chief Engineer Chi has finished his calculations and will answer the questions quickly.

"90 kilobytes!"

Gao Zhendong nodded: "Yes, 90kB. This capacity is sufficient for most existing applications."

In fact, this is not the theoretical limit capacity, but Gao Zhendong planned the formatted capacity to be this large. In actual operation, redundancy is required, which will occupy physical space.

The software at that time was not so feature-rich, and there was no other messy stuff at all. It basically only served the core target functions, so this capacity was completely sufficient.

Originally, we could have made double-sided products, but Gao Zhendong took into consideration the need to reduce the complexity of the first milestone product, increase the success rate, and speed up the development of equipment, so he simply put double-sided products on the back burner and just made single-sided products.

For this thing, the core is whether it exists or not. As for whether it is one-sided or double-sided, just leave it to the comrades to improve it.

Single-sided is also enough. The later 5.25-inch single-sided low-density disk has a capacity of 180k, and there is only one difference between it and Gao Zhendong's design - it has 40 tracks.

The two are actually similar in size, but Gao Zhendong reduced the track density considering the mechanical precision issues brought about by the different times.

Others couldn't join in the discussion of this topic because they didn't understand it at all, but Chief Engineer Chi and his team had no problem with it.

The comrades in the computing institute simulated, calculated, and thought for a while, and then expressed similar feelings to those of the later giant Bill Gate.

"90kB, that's a huge capacity."

"You can't use it up. Really can't use it up!"

"For individual users, 90kB is too large."

"That's enough. That's enough."

"..."

Looking at them, Gao Zhendong's cheeks twitched. He couldn't complain about them. Apart from other things, he was highly consistent with the goal god in this aspect.

They could only smile and say, "This capacity is enough for now, let's use it first." They were considering the capacity issue, but the comrades in charge of other parts had a lot of things to consider.

A group of old masters from the third factory had been discussing with each other for a while, and now they expressed their opinions.

"Chief Engineer Gao, we have calculated that this is equivalent to dividing 60 mm into 20 strips, each 3 mm. We don't know if other things support this, but from a purely mechanical point of view, this width is too large and a bit wasteful."

Having worked together for a long time, they knew that Gao Zhendong was very receptive to correct opinions and was very happy to listen to them. There was no such thing as pointing out the wrong ideas to his face. He was very happy, so they directly pointed out what they thought were the unreasonable aspects of Gao Zhendong's design.

Gao Zhendong was very happy. He designed 20 tracks to leave enough redundancy and reduce the difficulty of research and development. If he could increase the number, he would be more than happy to do so.

“How much can it increase to?”

"It's hard to say. The size of this thing is quite limited. The photoelectric encoder and transmission mechanism we have are a bit large. It is impossible to achieve the accuracy of some equipment, but 3 mm is definitely too large."

The accuracy of certain equipment naturally refers to the worktable of the lithography machine, which is only a few microns, 1000 times lower than this!
Gao Zhendong said: "There are photoelectric encoders that are 1 cm in size, but of course the accuracy is quite different. As for small transmission mechanisms, there are comrades from the Beijing Watch Factory here who can provide help."

Mr. Long of the Beijing Watch Factory smiled and said, "The transmission mechanism we developed is small in size, but also weak in strength. We need to enlarge it appropriately to increase the transmission performance. But I estimated that it is not a big problem. For us, it is relatively simple to start from small to large."

As the top in this field, the dragons always have their own pride.

"The only problem is that we don't have the right equipment to test whether the control results are in place."

For a watch, the hairspring is both a driver and a reference, which determines the movement state of the watch hands. How often and how much the hands move each time all depends on the hairspring.

But a hairspring cannot be used on this device, no doubt about it.

Mr. Long is not in this line of work, so the words he used were slightly different, but everyone understood his meaning.

When the old technicians of the third factory heard this, they laughed and said, "Boss Long, the photoelectric encoder that Boss Gao just mentioned is used for this purpose. With a suitable reduction mechanism, it can measure the movement more accurately. As long as you can fix the small transmission mechanism, we can handle the rest of the processing and other issues."

President Long was relieved: "That's easy, that's easy."

At this time, an old master raised another question: "Mr. Gao, it is easy to divide the lanes, but a circle should be divided into at least 9*512 segments, which is almost 5000. This requirement is a bit high. In such a small space, it may be difficult, especially in the inner circle."

In order to reduce the complexity of control, the sector division of the floppy disk is actually based on angle rather than arc length. That is, there are the same number of sectors from the inside to the outside, but the sector lengths are different, with the inner circle being the shortest.

Speaking of this, Chief Engineer Chi is no longer sleepy.

"This is not a big problem, master. The control of the sectors is actually controlled by the switching operation of the magnetic head. It is determined by the speed of the magnetic head reading and writing operation and the switching speed behind it. That speed is absolutely sufficient. Leave this problem to us. The mechanical part does not need to spend too much money on this aspect. The mechanical part only needs to ensure the uniform rotation speed of the disk."

The old master nodded and said, "That's no problem."

The comrades in the Operation Institute then realized the reason why Gao Zhendong divided the magnetic head control into two channels, each performing its own function, giving full play to the advantages of mechanics and electronics, and combining them to solve the problem with the simplest possible solution.

I admire you!
Seeing this scene, Gao Zhendong was happier than anyone else. Comrades from different units and positions worked together, brainstormed, divided the work and cooperated, and soon came up with a rough implementation plan for the new equipment. This was the result he wanted to see most.

He smiled and said, "Very good, it seems that this problem is not a big deal. The 3mm track spacing is the result of my leaving enough redundancy to minimize the difficulty of research and development. You can make adjustments according to the actual situation during the research process. In principle, you can only reduce it, not increase it. Of course, you still have to consider the situation of the magnetic head. The width required for the operation of the magnetic head is also a determining factor. In summary, try to reduce it as much as possible, but first ensure availability and reliability."

Everyone responded in unison, rubbing their hands in anticipation, and determined to get the job done.

We discussed the details for a long time and finally came to a rough agreement on the issues concerning the 15cm disk drive and disks.

Gao Zhendong concluded: "I will take the lead in this matter. Chief Engineer Chi, you have more experience in this area, so I will leave the early stage work to you."

When it comes to computer peripherals, Gao Zhendong broke with his habit of being a hands-off manager like JP-59, XS-59, and DY-60, and took charge personally. It was not because he had so many ideas about these things that he was reluctant to share them with others.

It's because there are too many units involved in this matter. Even the Audio-Visual Corporation and the Haihekou Record Player Factory will be involved because of the magnetic heads and discs.

If he doesn't take the lead personally, others may not be able to control the situation, and that would be embarrassing.

A wise person will not turn a good thing into a bad thing.

(End of this chapter)