Technical questions about the blockchain, where is the data stored, what technology is used and how do the nodes communicate?

Question

P2P

There is a lot of theoretical information about blockchain on the net. But I have some technical questions.
1) Where is all blockchain information stored?
There is no single server in the blockchain network, and all network nodes must have access to information. All information cannot be stored on each computer participating in the network?! If this is a network with a small amount of data, it's still all right, but if the volume grows? And if one computer is involved in several such large networks?
2) The contents of the blocks and their relationship is already known to everyone who is interested, and even a beginner in programming will be able to implement them no matter what programming language he knows. But what's next? How is the interaction between different nodes? What technology and library options can be applied? What do you need to dive into learning if you are expanding your personal stack specifically for the blockchain? Something like this: programming_language[library] + programming_language[library] + server[config_option].
3) There are no ideal programs, sooner or later they need updates. How does this fit in with "an immutable running blockchain" and what are the implementation options, if any?
PS I am considering blockchain not in the format of cryptocurrencies, but in the format of a new generation of technologies that can increase freedom on the Internet. I would be happy with code examples (in any programming language), descriptions of algorithms in Russian, and just reasoning and additions to my questions that can develop a train of thought in a productive direction.

Answer 1

1) these computer problems
are stored on the nodes, as a rule, completely (for now), in 200GB bitcoin, Ethereum about 80, tolerably
there are tools to store blocks from the end, that is, not the entire blockchain
2) Go learn, pick in the code. A beginner can, but x% & in
3) look at the Word file that opens with different versions. And the word HARDFORK
will be written here for you, yeah))
"dcentralized search give me coins no money"

Answer 2

I just wrote a review article on p2p networks in March , read it.