This number is encoded as a variable-length integer, see the txn_count in the block protocol message.
The idea is the following:
Read the first byte as marker
If marker < 0xFD
marker is the number
If marker == 0xFD
read the next 2 bytes as the number
If marker == 0xFE
read the next 4 bytes as the number
If marker == 0xFF
read the next 8 bytes as ...
If we call the winner, the miner that solves the PoW problem first, then how do we know that he received all the transactions he's supposed to receive before announcing that he created a valid block?
Why should we care? He can include whatever transactions he wants, it's his block. If he ignores lucrative transactions, he'll lose money because he won't make ...
From a novice, what it means that if someone who isn't bitcoin savvy accepted bitcoin on the deprecated block and gave that person something of value, that person is out of luck, you just lost that item of value.
Previous answers eluded to it, but, simpletons like me look at "So what does this really mean". It means, when you get paid in BitCoins, ...
nBits is a compressed representation of the target value that the block's hash must be less than. Bitcoin does not actually care about difficulty. Difficulty is just for humans to think about how much work is actually being done. Bitcoin only cares about nBits and the target value it represents. A block's hash must be less than that target value. nBits is ...
There are two values in play here, and the way your question is phrased makes me think you're confusing them.
Every block has:
A hash (computed by double-SHA256 the block header, including timestamp, nonce, version, Merkle root, nBits which encodes the difficulty, and previous block hash)
A target (computed from the difficulty only)
I think you're confusing a few things.
A SHA-256 hash is a single value that is 64 hexadecimal characters long. This hash can be seen as simply a very long number.
A target hash in cryptocurrencies is the maximum value that a successful block hash should be. Miners are aiming to generate a block where the hash, when seen as a large number, is a smaller ...
The comparison used is numeric
These are numbers not strings of characters. You can see this by looking at the code in the 2009 main.cpp of the Bitcoin reference implementation:
uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
if (hash <= hashTarget)
Once the mining pool has the list of all of the transactions they are including in that block, they calculate the merkle root for this list of transactions, then they distribute the block header, that includes the merkle root, to miners to work on.
So, no, it's not constantly being updated, unless for some reason a new transaction was being added or removed ...
Have you read this? It is sort of technical, and goes into How is difficulty calculated? and How is difficulty stored in blocks?
re your comment about nonces: The nonce is not the difficulty. In the example below, I'm trying to find a sha256 that starts with 0. On my imaginary blockchain, a proof-of-work that starts with ...
I got it to work by adding
to the config file.
The reason is your wallet needs to connect to nodes to connect to the blockchain. Usually it comes with all the nodes required to connect, but sometimes the devs failed to include the nodes or released ...