Finally got my full node running for the first time since 2011. I’ve got it set up on two separate machines. So, what exactly does a node store, and what doesn’t it save from before the whole wallet thing started? Back in the day when I was mining, wallets didn’t show all the available coins.
You may have misremembered it, there's no such "pre-wallet era".
In the very old versions including the first release, Bitcoin Core will create a default wallet for you.
The difference is:
You'll have to explicitly create a wallet in the new versions and it's possible to have multiple wallet.
It wasn't possible to create multiple wallets back then aside from manually swapping wallet.dat files.
For mining in the old version: When you tick "Generate Coins", it'll auto-select one of your wallet's address in the background.
And of course, it will not show coins if you didn't mined a block since it's solo mining (either 50BTC or zero, not a coin or two) or no one sent you bitcoins.
So a node doesn't save anything? What would be the importance of an earlier node aside from the cool factor? Wouldn't the node still be able to sign for transactions with coins related to said node? I have an idea which transactions were ones that I made. For example, a set of transactions that occurred around July '09 where I consolidated 200 addresses into a 10k coin address for the "cool" factor when a friend of mine asked if it was possible to put that many coins into one address.
I don't know what exactly you mean by save. But in short, Bitcoin node keep partial/full blockchain data and UTXO set.
You need to explain what cool factor means. But,
1. You just need full node to get relevant transaction associated with address on your wallet.
2. There's no thing such as certain coin/UTXO related with specific node.
I don't know what and how you describe node, Bitcoin node act as servers to store blockchain data, this will answer you query on what a node saves, if your definition of save and store are the same.
No idea about the earlier node running, i met the updated version of it. Currently running a pruned node but it all works the same way with a full node only that pruned ones don't store the whole blockchain data after validation.
Something like that? https://mempool.space/tx/e67c7cef9c59167046bee99a961a4ca75137c5ed4b697b30dc6e752ff1d50ecc
In general, if you still have the same wallet, then you can sign messages from the old keys, even if coins are no longer there.
So, it is possible to for example sell coins in the past, and prove now, that you had them. But you should be careful, because even if it is "cool", then by correctly proving, that you had for example 10k coins, some people may want to attack you, if they will think, that you secretly still have a lot of money.
The Bitcoin blockchain runs on what is known as a public ledger which contains a hierarchy and stack of transaction data and origin including time stamps in a particular arrangement through something known as Merkel tree. Basically running a node simply means having a copy of that public ledger. The fact is all miners run nodes the difference is being able to use hashrates to include transactions in a block and also confirm them.
One of the advantages of running a node is if you have a wall you can use your node to broadcast transactions meaning you have increased privacy since you are not depending on other nodes.