Chapter 848 The Confusion of the Russians
"Davari, this computer seems to be a little different from the DJS-60D." Another Russian is very familiar with DJS-60D, he is a copy of DJS- Comrade Vitali of 59.
As a top computer expert in this field, Vitali was naturally invited to this research group even though he knew that this new switch was controlled by computers. He was the most familiar with Southern gay computers. One of the people.
It's indeed different. Switches and ordinary computers are different after all. Gao Zhendong directed the comrades of the Institute of Communications and designed some special circuits to complete some special functions. Moreover, the chips used in these circuits and the input and output rules are all It's strange, you have to cooperate with the program to barely test it.
There are no serious logic analyzers these days, and these special circuits are the first difficulty for some small actions.
"I saw it, but I am confident that sometimes I can use the black box mode, regardless of the internal, the functions can be analyzed based on other circuit parts. Directly doing this function circuit may meet the requirements, and it doesn't matter if it is not integrated. If not, We can polish it, but the quantity is not large, it doesn't matter." There is an angle grinder to guarantee the bottom, and the other person thinks it's not a big problem.
He is Anatoli, who is responsible for imitating DJS-59 with Vitali, and is more responsible for the specific work, and is very familiar with this aspect.
At this time, someone had already found the memory of this program-controlled switch along the connection.
This control computer is based on DJS-60D. As long as people familiar with its interface, they can easily find the memory based on experience, and can distinguish program memory from running memory.
It looks like running the memory...is a little abnormal.
But this is not a big problem, the biggest problem is that there is no program memory!
Anatoli looked at running memory and turned to his colleagues.
"Davari, why do they connect two batteries to the running memory? And not to be disconnected? And there is no program memory?"
A colleague shrugged: "Maybe for the sake of high reliability, they always have endless fantasy ideas. Ha, they really want to cost and actually store the program directly in the running memory."
This kind of operation, There are some when using magnetic core memory, and it is very common, regardless of operation and program memory. Anyway, the magnetic core is powered down, and the addressing space and physical structure are actually put together.
When the Southern Comrades came up with a general computer architecture, they separated the two. The program memory could use low-speed and cheap media, and the running memory would use high-speed media such as RAM chips, which took into account both cost and speed.
But unexpectedly, Comrade Nanfang restored this structure on the program-controlled switch. Perhaps it was for the purpose of operating speed and business recovery speed, and it could be put into use immediately after powering on.
This method is not very expensive compared to the tape and the latest floppy disk drives they saw not long ago, especially the larger the program capacity, the more prominent this problem is. The program capacity of the program control switch is not small.
"Maybe it is for the running speed. By the way, since the running memory and the program memory are combined, it needs to be powered down, otherwise the program will be lost. Perhaps these two batteries are for this purpose. The reason for the two is one main and one backup, in order to improve reliability and to easily replace the battery when necessary," someone analyzed.
The battery can be charged, and it usually doesn't need to be replaced after connecting to an external power supply. However, they always break down or do not connect to power for a long time. At this time, one main and one backup will be useful.
Russians are very clear that RAM loses data when power is lost. In this two-in-one structure, in order to ensure that the program is not lost, a battery is indeed needed to maintain data when power is lost, and the power consumption of RAM is not high. , the battery can hold its data for a relatively long time.
It is important to admit that these Russians have completely correct ideas. At first glance, they can analyze the situation and reasons in this part of the situation and reason.
"Is that so?" Anatoly looked at the not-so-large battery, and turned his attention to the pile of running memory chips on the circuit board with significantly different packaging, with a slight premonition in his heart. .
That kind of packaging looks very much like an epoxy resin packaging. The southern colleagues gave it a name called "Cow Dust Package". Looking at the chips, I have to admit that the Southern comrades Describes very vivid.
But that's the problem, why do they use this cow shit package on the running memory?
Their RAM is all standard packages and can be directly assembled using standard chips. Why do they use this package in one go? This is not good for manufacturing and management.
Unless... they have a reason to have to do so, or the RAM chips they use on program-controlled switches are somewhat different from ordinary ones and cannot use standard packaged ordinary RAM chips.
Even following this question, he thought of a more important question, why do they use such a expensive memory structure? Large-capacity floppy disk + small-capacity RAM is the solution that can take into account both cost and performance.
As the inventor of these devices, Comrades in the South could not have known this. Even those who make program-controlled switches could not have imagined it, but their Davari, who studies computers. Gao must be able to take this into consideration.
Thinking of this, Anatoly felt even more uneasy.
"Can the program be read out?" Whether the program is read from the program memory or is originally in the running memory, as long as the program enters the running memory, it must be executable, and reading out has a huge effect. This judgment makes He let go of his concern. "We will try it," a technician replied.
The most important thing about reading programs is naturally placed at the highest priority level.
The people in the old Russian imitation group are all the top-notch. Within one day, the work of trying to read is quickly tried once. The memory read and write interface is universal, and this job is not difficult. Finish.
"Suka no! The programs and data read are completely messy!" An old man in charge of data reading looked at the results of the preliminary decompilation and cursed.
"Impossible! Programs and data in running memory cannot be encrypted, and the operator does not have the ability to encrypt and decrypt data during operation." Anatoly retorted, DJS-60D and DJS-59 is not much different in actual structure, he is very clear about it.
Not to mention that at this time, even after decades, the data in the running memory will not be encrypted.
After saying that, he carefully observed some of the data. His solid foundation and rich experience made him feel that these seemingly messy instructions and data actually have certain rules. "They messed up the program!" Anatoly exclaimed.
Although the decompilation result seems to be inconsistent, Anatoly still sees that this chaotic result is actually an integral part of a huge program, but it is completely disrupted and has no actual value at all.
No mistakes, one poem, one post, one content, one in 6, one book, one bar, one read!
"Article out-of-order mapping of addressing?" As one of the top two people in computers, Vitali didn't know how to describe this technology. He used a phrase he invented to describe it. he.
Although he invented this phrase, Anatoly understood what he meant.
"Yes, yes! It's an out-of-order mapping of addressing! This cannot be encrypted data. If it's encrypted data, it's impossible to decompile so many seemingly normal single instructions, from From this point of view, it is basically certain that it is still plain text. Moreover, the computer's calculator cannot support decryption at runtime, which is a huge waste of computer computing power."
Anatoly said his analysis. The encryption he mentioned is not a simple method such as replacing letters or circular shifting. It is like not encrypting, but a serious encryption and decryption, similar to Gao Zhendong's defense worker. The data encryption algorithms they built are very consuming computing power.
Vitali nodded in agreement: "So they used a simple method to disrupt the address and actual address of the running memory and remap it, so that it would be normal to read it Although the data read from the fetching instruction is plain text, it is completely disrupted. For programs with extremely high requirements for the sequence structure of the front and back, it also achieves the encryption effect. "
Anatoly feels I found the key to the problem and laughed.
"Hahaha, no matter how they disrupt it, there must be two places where this mapping relationship is. One is where the decoder issues instructions to the finger fetcher to read, and the other is the memory address decoding Where, as long as these two locations are found, any of these two mapping relationships that are inverse operations can help us solve the mystery. "
Vitali patted his shoulder heavily : "My Davari, you're right!"
The other comrades next to them looked at them and admired them very much. This is our top computer expert, Ula!
Then the two looked at the circuit board and fell into deep thought.
Who is who is the chips on the main control board with shiny tops polished?
Forget it, this is too complicated and there is too much unknown quantity. It depends on the memory side.
The memory chips all look the same, and the rest are mostly related to the unsorted mapping address decoding function, which is simple!
Then, they looked at the pile of exactly the same "cow shit" on the storage board and fell into confusion.
Who is this the hell?
After a brief confusion, Comrade Anatoli raised his head. "Don't worry, we carefully analyze their circuits, and take some time to find out this functional structure quickly according to the direction of the circuit."
Vitali and other comrades clicked Head, it makes sense.
But, is this really the case?
(This chapter ends)