Chapter 185 Transit Server, Compression

Matthew first asked a question in the chat channel. His ID on the network is MAX.

[MAX: There must be a [revolution] life function, so that those who have been cracked are willing to re-download our upgrade program.]

[Left hand: Everyone says that there are too few things that can be stored in it. Can we think about increasing the storage space?]

Left hand (LEFTHAND) is the new student of the Massachusetts Institute of Technology. He has a lot of research on hardware. He successfully cracked a series of calculators from Hewlett-Packard. After publishing the cracking program to the BBS of the SAM Association, he was admitted as a member of the SAM Association.

After this cracking program came out, the famous Mr. Wozniak actually praised it, because he was a calculator engineer at Hewlett-Packard. He had always wanted to release these functions, but he was not allowed by the company. It was finally cracked until today.

At the same time, he also spoke highly of HELLC, the first to launch a calculator cracking program, believing that HELLC is equivalent to creating a technical research genre. Calculator is a product that appeared earlier than computers. Today, it has become closer and closer to computers in terms of functions. He is very optimistic. This unique platform.

Wozniak also specifically mentioned the infrared transmission protocol used in the cracking program, and said that if he had such a powerful protocol when he founded CL9, a company specializing in designing universal remote control, he would not have sold CL9 prematurely.

Due to the establishment of Apple, Wozniak has a high position in the technology circle. He actually appeared in the BBS of the SAM Association, which undoubtedly brought unexpected publicity effects to the SAM Association.

It is also for this reason that the infrared transmission protocol used by all cracking programs in the SAM Association has begun to attract widespread attention.

[Eagle: The flash memory of the calculator is fixed, increasing the storage space, unless the flash memory is replaced. Small batch calculators are fine, but if you want everyone to modify them. But this is not realistic at all, unless the manufacturer takes the initiative to upgrade it. We have discussed this issue before.]

Arthur is still used to using his usual ID "KITTY_HAWK".

The bottleneck of

memory does greatly limit the function of the calculator. Some larger programs cannot be installed for this reason. He and Lin Hong are planning to try to transform their calculators, but that's all. It is impossible to transform everyone. Too much work.

[Torch: I have an idea. Maybe we can consider using infrared transmission to make up for the lack of storage space. As long as it is more convenient for everyone to install the program, install it when you want to use it, and delete it when not in use. The torch is another new member who is more good at hardware. He is not The student, according to himself, has joined the work and is currently a small employee in a telecommunications company. The profession and technology he is engaged in have nothing to do with it. Technology is just his hobby.

[MAX: How to make up for it? Keep talking.]

[Torch: For example, we can modify some calculators to increase the coverage of storage space and infrared wireless, and use it as a transit server. Once they want to install the program, they can directly connect to the server and get the above data. When they don't need it, they can use the installed Delete the program.]

[MAX: Good attention!]

[Atom: It should be feasible in theory, so that we can also develop more interesting software in a targeted way.]

Atom, one of the new members, is good at software development and is a high school student in Alaska.

[Eagle: The transit server can be not only a calculator, but also a computer, and if it is a networked computer, it will be more interesting.]

The torch's proposal was unanimously approved by everyone.

This is indeed a very creative idea. As long as you modify a part of the computer, you can achieve good results.

Hearing the relay server, Lin Hong remembered his "CQCQ" software. Maybe he can also port this software to the calculator platform?

However, in the end, he still didn't say this idea. Let's talk about it later. If there is really a possibility of realization, it is also a good thing, but it also involves many technical problems that need to be solved. Lin Hong plans to improve the PC version of "CQCQ" first, if it is really necessary. It's not too late to transplant again.

However, in addition to this idea, Lin Hong also thought of another good idea.

[HELLC: I also have an idea. Although it is difficult for us to increase the size of storage space, we can start to improve it from another perspective, that is, to reduce the volume of software and data.]

[MAX: I know! That's right, we can compress the data, which can greatly save storage space!]

[Eagle: Yes, this method is more feasible.]

Several other members agreed with Lin Hong's idea. They all said that it was indeed "HELLC" who thought things were indeed more meticulous than them.

Among the original trio of SAM, Lin Hong was the most respected one. After all, he cracked the calculator himself and developed an infrared wireless transmission protocol with high performance.

The first point is the root cause of the establishment of the SAM Association, and the second point is the important driving factor that the cracking program can spread quickly and compete with other associations.

Before that, their software or data files were stored in the calculator at the original size without any processing. The original size was stored in the calculator.

Then, they began to discuss how to achieve data compression.

Due to the lack of early computer storage space, the need for data compression in computers existed from the beginning. As early as the 1940s and 1950s, Claude Shannon, a famous American mathematician, founder of information theory and genius, published a basic paper in this regard, laying the theoretical foundation for data compression.

Previously, the most popular compression software on major BBS in the United States was mainly ARC developed by SEA, which is a commercial compression software. If you use it, you must buy it with money.

Later, there was a hairy guy named Philip Katz. He is also a big fan of BBS, but he is short of money. He saw that he had to pay for even compressing a file. So I developed a similar software by myself, which is free for everyone to use.

The name of the software that Philip has just started to develop is "PKARC". The first two letters are the abbreviations of your first name and last name. The following ARC naturally refers to the commercial software ARC, because the software released by SEA at that time also included part of the source code of C language. According to the content, he wrote a similar software, which is fully compatible with ARC.

In this way, everyone immediately became a loyal user of PKARC. Seeing this situation, SEA immediately took Philip to court, so the court ruled that Philip was prohibited from continuing to develop and disseminate PKARC.

But the lawsuit did not wipe out Philip's fighting spirit. Like most hackers, he advocated [from] and free, so a few weeks after the end of the lawsuit, he developed another software called "PKZIP".

"ZIP" means "fast" and "flying by" in English, which is usually described as bullets passing by "ZIP". Philip took the name, which means that the software he wants to develop will be faster and more powerful than ARC.

Obviously, he succeeded. In just a few weeks, the PKZIP software he developed can compress one or more files into a suffix. The ZIP file exceeds the commercial software ARC in terms of compression ratio and compression speed.

More importantly, his software no longer refers to the ARC algorithm, but uses a new compressor system, and he announced that it is no longer compatible with the ARC format.

In this way, Philip took PKZIP as [Since the free release of the software], it was immediately welcomed by the webmasters of the major BBS in the United States, like a spark, and quickly spread on the major BBS in the United States. Webmasters have begun to convert the original ARC format compressed files to ZIP format.

SEA soon completely disappeared from everyone's eyes, and the ZIP format became the standard format for compression software in the Internet era.

The SAM Association wants to compress the data. ZIP is the most ideal choice. Although there are still some other data formats on the market, such as ARJ, LHA, CAB... and so on, these compression formats are either patented products and need to be paid or the compression technology has not been published. For details, only Philip, the author of ZIP, released all the technical information of ZIP compression two years ago.

Therefore, the SAM Association finally chose ZIP as its own compression format.

But there is still a problem, that is, the compressed file is transferred to the calculator. How to read the data inside?

Obviously, PKZIP cannot be used to read directly. There is only a little place in the calculator, and PKZIP cannot be ported at all, and the corresponding decoding program can only be written separately.

If you want to write a decoding program, you must understand the compression algorithm used in the ZIP format, that is, the "LZR algorithm", which is a lossless data compression algorithm. That is to say, what it is like, what to do after compression and restoration, no one byte is missing.

The principle is actually very simple, because the data in the computer is represented in binary, and only "0" and "" sometimes ten consecutive numbers may be "", so it can be directly marked as "there are 10 here" instead of really filling with ten "".

In this way, compression can be achieved.

Of course, it's easy to say, but it's quite complicated to do.

Among the members of the SAM Association, all of them have not been exposed to compression, and everyone must learn from scratch.

Therefore, everyone began to divide the work. Lin Hong was responsible for the development of the new cracking program. He not only integrated the advertising system into it, but also had to leave the location of the decoding program. After Arthur and Atom wrote the decoding program, they would integrate it. In addition, according to the principle of more work for the capable, Lin Hong has to work with the torch and the left hand to upgrade the calculator.