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Chapter 185 Transit Server, Compression

MAX: Tell me, what are the areas that can be upgraded?

Matthew first asked the question in the chat channel, and his ID on the network was Max. Pen & Fun & Pavilion www.biquge.info

MAX: There has to be a revolutionary feature that will make those who have already cracked it want to re-download our upgrade.

Left hand: Everyone says there's too little to fit in, can we think about increasing the storage space?

Lefthand was the new MIT student, who had a lot of research in hardware, and he successfully cracked a series of Hewlett-Packard calculators, and after publishing the cracks on the BBS of the SAM Association, he was accepted as a member of the SAM Association.

After this cracked program came out, the famous Wozniak even expressed his appreciation for it, because he was a computer engineer at Hewlett-Packard and had been trying to put these features out, but he was not allowed by the company, and it was not until today that he was finally cracked.

At the same time, he also made a high evaluation of HELLC, the first to launch a computer cracker, believing that HELLC is equivalent to creating a school of technical research, and the calculator is a product that appeared earlier than the computer, and today, it has become closer and closer to the computer in terms of function, and he is very optimistic about 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 the design of universal remote controls, he would not have sold CL9 prematurely.

Due to the founding of Apple, Wozniak has a high status in the technology circle, and he actually appeared in the BBS of the SAM Association, which undoubtedly brought unexpected publicity to the SAM Association.

It is 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 calculator's flash memory is fixed, and the storage space is increased, unless the flash memory is replaced. It's okay to have a calculator in small batches, but if you want everyone to modify it, it's not practical at all unless the manufacturer actively upgrades it. We've talked about this before.

Arthur is still accustomed to using his usual ID "Eagle (kitty_hawk)".

The bottleneck of the memory does greatly limit the function of the calculator, and some relatively large 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, and the workload is too large.

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 easier for everyone to install the program, install it when they want to use it, and delete it when they are not in use.

Torch is another newcomer to the hardware industry, he is not a student, according to himself, has already joined the work, is currently a small clerk in a telecommunications company, he is engaged in a career that has nothing to do with technology, technology is just his hobby.

MAX: How to make up for it? Go on.

Torch: For example, we can modify some calculators to increase storage space and infrared wireless coverage, and use it as a relay server, once they want to install the program, they can directly connect to the server, get the data on it, and when they don't need it, they can delete the installed program.

MAX: Nice attention!

Atom: It should be theoretically possible, so that we can develop more interesting software in a targeted manner.

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

Eagle: A relay server can be not only a calculator, but also a computer, and it's even more interesting if it's a computer connected to the Internet.

The proposal for the torch was unanimously approved.

It's a very creative idea, and you can do it with just a part of your computer.

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

However, in the end, he still didn't say this idea, let's go back, if there is really a possibility of realization, it is also a good thing, but there are still a lot of technical problems to be solved, Lin Hong plans to improve the PC version of "CQCQ" first, if it is really necessary to transplant it again.

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

HELLC: I also have an idea that while it's hard to increase the size of the storage space, there's another way we can start improving it, and that's to reduce the size of the software and data.

Max: I see! That's right, we can compress the data, which can save a lot of storage space!

Eagle: That's right, it's more feasible.

Several other members agreed with Lin Hong's idea, and they all said that it really deserved to be "hellc", and they thought that things were really more detailed than them.

Among SAM's original trio, Lin Hong is the most admired one, after all, it is the calculator he cracked by himself, and developed an efficient infrared wireless transmission protocol.

The first point is the fundamental reason for the establishment of the SAM Association, and the second point is an important driving factor for the cracking program to spread quickly and compete with other associations to get ahead.

Before that, their software or data files were stored in the calculator at their original size, without any processing, and they were stored in the calculator as big as they were.

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

As early as the forties and fifties, the famous American mathematician, the founder of information theory, and the genius Claude Shannon published a basic paper in this area, laying a theoretical foundation for data compression.

Previously, the more popular compression software on the **BS in the United States was mainly ARC developed by SEA company, which is a commercial compression software, and if you use it, you must spend money to buy it.

Later, there was a hairy guy named Philip Katz, who was also a BBS fanatic, but he was shy of money, and he saw that he had to pay for compressing a file, so he developed a similar software himself, which was free for everyone to use.

The name of the software that Philip just developed was called "PKARC", the first two letters are his first name and last name abbreviation, and the latter 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 the C language, and he wrote a similar software based on its content, which can be fully compatible with ARC.

As a result, everyone immediately became loyal users of PKARC, and SEA immediately took Philip to court, and the court ordered Philip to prohibit the further development and distribution of PKARC.

But the lawsuit didn't dampen Philip, who, like most hackers, advocated freedom and freedom, so a few weeks after the lawsuit ended, he developed another piece of software called "pkzip".

"Zip" means "fast" or "swishing and flying" in English, and is usually used to describe the bullet "zip" by, and Philip took the name to mean that the software he wants to develop will be faster and more powerful than the arc.

Clearly, he succeeded. In just a few weeks, he developed the PKZip software, which can compress one or more files into a file with the suffix ".zip", which surpasses commercial software ARC in terms of compression ratio and compression speed.

What's more, his software no longer refers to the ARC algorithm, but uses a new compression mechanism, and he announced that it is no longer compatible with the ARC format.

In this way, after Philip released PKZIP as free software, it was immediately welcomed by the webmasters of all **BS in the United States, like a spark, and quickly spread on **BS in the United States with the momentum of a prairie fire. Webmasters have begun to convert the original ARC format compressed files to Zip format.

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

The SAM Association wants to compress data, and zip is the ideal choice, although there are some other data formats on the market, such as arj, lha, cab...... And so on, but these compression formats are either patented products and have to be paid, or the technical details of the compression are not published, only the author of the zip, Philip, published all the technical information of the zip compression two years ago.

So, the SAM Association finally chose ZIP as its 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, you can't use pkzip to read it directly, there are only so many places in the calculator that you can't port pkzip at all, you can only write the corresponding decoder program.

In order to write a decoder, it is necessary to understand the compression algorithm used in the zip format, the "LZR algorithm", which is a lossless data compression algorithm. In other words, what was the original like, what happened after compression and restoration, not a single byte was missing.

The principle of this is actually very simple, because the data in the computer is represented in binary, only "0" and "1", sometimes ten consecutive numbers may be "1", then it can be directly marked as "there are 10 1s here", instead of really filling in with ten "1".

In this way, compression can be achieved.

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

None of the SAM members had ever been exposed to compression, and everyone had to learn from scratch.

So, everyone began to divide labor and cooperate, Lin Hong was responsible for the development of a new cracking program, not only to integrate the advertising system into it, but also to set aside the position of the decoder, and wait for Arthur and Atom to write the decoder program, and then integrate it. In addition, according to the principle of more work for those who can work, Lin Hong also had to work with the torch and his left hand to start upgrading the calculator.

……