WRIT - you message?

Well hello, amateur-habra railwayman!
Today, finally, I will continue to broadcast on the railway, but already in a more thematic framework of Habr ... [joke /]
Remember, I often spoke about the information space of the Belarusian railway? Well, on it today and dwell ...
Each technological operation performed on the road is accompanied by an information flow. The flow is formed from the so-called messages transmitted from the station, when performing a technological operation, to the Main Settlement Information Center (hereinafter referred to as simply VC).

The message is a banal text file in which, in a certain way, in the form of an ordered sequence of characters, information is recorded about the technological operation, relative to which it was formed.
Each message is formal and logical control. Logical control - checking the adequacy of recording dates and times, etc. Formal - specialized, for compliance with any signs, for example, a sign of the beginning and end of a message.
All messages begin with the characters "(:" (the opening bracket is a colon)) and end with the characters ":)" (the colon is a closing bracket), between which the same, in a certain way structured information should be.
For each message sent to the CC, a response is generated, allowing either to obtain the requested information or to judge the correctness of the message request. Replies are sent to all messages.
The simplest example is a test message to test the connection.

(: 1111 :)

in response, the subscriber will receive the following message

(: 497 --
1 0 -- :)

')
it is here that the analysis takes place (according to the key U1, if oh everything is fine, if 1 is good, but with shortcomings, 9 is not good). Instead of “blah blah blah”, of course, there is information of internal order.

Messages are of several types:

• reference information
By requesting such a message, we receive reference information: standard names, technical specifications, etc.

• information and analytical
By requesting such a message, we get information that tends to change over time: information about the location of cars, trains, locomotives, about the performance of technological operations, performance indicators generated over a certain period, etc.

• managed
This type of messages is the most important, since it is with these very messages that the information model of the railway is formed. In these messages, unlike previous ones, we do not receive information, but form it ourselves.

• messages about the cancellation / correction of "managed" messages. Since there are no systems with artificial intelligence (it says even more about expert systems and knowledge bases), unlike some other countries (read Germany and someone else there), there are still people working at the stations, as you understand, no one is immune from mistakes.

Thus, all interaction with the information model of the railway is in the proper compilation of messages and the receipt of satisfying requests.

Let's now figure out how the information from the station goes to the EC
Each message, as I said, is a text file. Our file must be named in a certain way. It is the name of the file that characterizes its fate ("as the file you name, so it will float")
Here is the mask for the file name.
XXYY 0000. ZZZ
where XX is the logical number of the recipient
YY - the sender's logical number
a bunch of zeros - they say a reserved place (although there are suspicions that they just finished it up to 8.3 format)
ZZZ - the sequence number of the message sent

Now the next moment, in the process of transmitting information to the railway, such a simple program called KI (information hub) is used, this is a kind of distribution point. More about this program in the near future, and now a small introductory.

From the sender (station) to the recipient (CC) can be from one to an infinite number of KI. The same hub may be one. Similarly, by communicating the station and the CC, with the help of the CI, it is possible to combine the stations for information exchange than we (the informants) and use when creating the speakers :)


Each CI has information about the so-called "auto answer" (a sort of analogue of IP) and the corresponding logical number. Remember, a little higher, in the structure of the file name used logical numbers of the recipient and the sender? Well, now the whole chain is created.
In short, the program works as follows: the newly created message is saved in a specific directory, in the form of a file, in the name of which the recipient and sender are specified. This directory is constantly "monitored" by CI. Having determined that there is a file, the next step is to read the recipient and, ... after a little thought, transfer the file to the appropriate recipient in a specific directory. It remains only to use the workplace program to read this file and then do its job. This situation describes when there is only one hub between the sender and the recipient, if there are several, the first hub, defining the recipient, shifts the file to the directory of the next hub and so on the chain until it ends up))))
You ask why you can not use something else? Well, it happened from time immemorial, they say that earlier, when communication channels were weak, this was the only best way out. It remains only to believe.
But do not worry, all transactions and replications are used at full speed, though only in some tasks related to the microsft sql server, but this is more technical communication, and the messages are railway technology, let's say, times are hectic, so everything can change) ))) Only tssssss, to anyone;)

Now, having more or less general notions about the principle of creating the information model of the Belarusian Railways and interacting with it, I will try to present an example, as they say on the fingers ...
Task: to track the exchange of messages in the system accompanying the movement of the train.
At 8:00 a train is sent from station A, by appointment to station B. At the same moment a message was formed and sent to the CC with the corresponding information. Literally at the same moment, stations B and C automatically received information that a train departed from station A.

Then at 9:15 the train arrived at the station B. The station sent a corresponding message to the EC. Similarly, station B received information that the train arrived at station B at 9:15.

At the moment, there is already a formed information model (it would be more accurate to call it a train model) and now from 8 to 9:15 we can trace the information we need, and we know the real position of the train in the road space.
Not even 16 minutes passed, as at 9:30 our train departed from station B, about which it was informed in the form of sending a message to the EC. Again, station B receives information about what happened.

Well, now I think it is clear what is happening: the train arrived at the station at 10:20 and the corresponding message was sent. Further, as necessary, various technological operations are performed, about which information is also received in the EC.

That's all, we have formed a simplified train model. In our example, station B received information about the train after each technological operation. The fact is that there is such a thing as the depth of information , it is measured in hours. Adopted the depth of information optimal for work and making operational decisions in the amount of 4 hours.
Let's say the distance between our stations is 110 km each. Thus, the distance from station A to station B is 220 km. Suppose our train moves at an average speed of 60 km / h. Then from station A to station B he will reach in 3.7 hours, which satisfies the depth of information. If the speed were less or the distance was greater, then, probably, only station B would automatically receive information on the departure from station A

As always, everything is superficial, for general understanding, so to speak.
Thanks for attention. See you soon.

ps
If you are still concerned about the question of what is written and what is behind the logo with a locomotive.
Well, I open a secret - WRIT - W orld R ailway's Information Technology (in my own free translation - the Railway world of information technology). It’s just that there is no possibility to create a corresponding blog - this abbreviation will accompany the cycle of my articles by yourself. The logo will color to the opening. For him, by the way, thanks to a friend GeNNke.
pss
Soon the day of the railway, so I activated)