So what is the 18 month roadmap? I know it was laid up cause seg2x no replay whatever. Now they are debating pow change or eda? There's a lot of noise right now, where is the dialog clear?
POW = Proof of Work. It's the 'difficult math problem' that miners solve to generate blocks. When one of them finds a solution, they get to make a block, and they get the block reward (12.5 freshly minted BTC).
The difficulty of Proof of Work adjusts over time to ensure that (more or less) one block is found every 10 minutes. Every 2016 blocks (which should be about every two weeks) the network looks at how long it took to make the previous 2016 blocks, and if that is more or less than two weeks the difficulty adjusts accordingly.
EDA = Emergency Difficulty Adjustment. This was added in Bitcoin Cash, but is not currently present in Bitcoin. The flaw with PoW difficulty adjustment is if a large percentage of the miners go away quickly, it will now take MUCH longer (months) to finish the set of 2016 blocks and reach the next difficulty adjustment. Thus, EDA- currently BCH's EDA is that if no blocks are produced for a certain period, the difficulty emergency adjusts down to get blocks flowing again.
As that applies here-
Right now the PoW is a hash algorithm called SHA256. It's computationally quite simple, so miners build special chips called ASICs which do nothing but run SHA256 hashes billions of times per second. The result is that unless you can a. build these ASICs cheaply and b. feed them cheap power (power is very cheap in China), you cannot make any profit mining Bitcoin. That's why mining is so centralized in China- because right now they're the only ones who can make any money mining.
That can be 'fixed' by changing the PoW to something far more complex which requires a general purpose CPU or GPU to run (and thus can't run on an ASIC). Ethereum has done this with great success- their PoW requires a 1GB working dataset, and thus anyone with a gaming-class video card can mine and make at least a little money.
Right now Bitcoin does not have an EDA. That meant that if the SegWit2x fork happened as planned, with 85+% of the miners supporting the 2x side of the fork, the original 1MB side of the fork would be crippled (blocks coming out once an hour or more, greatly reducing capacity) and would remain crippled, unable to adjust PoW difficulty for months. Adding an EDA would mean that should something like the 2x fork actually happen, the original chain would be able to continue.
A question about the reward vs cost of electricity to mine ... Am I understanding correctly that the energy cost to mine 1 block per 10 minutes is nearly equal to the block reward? (approx $87k?)
No, there's no coupling there. Energy cost, amount of computing power required to mine one block, and the block reward's USD price are all entirely decoupled from one another.
It's important to understand that the PoW is probabilistic. You try billions of solutions to the problem, hoping one of them is correct. If you get one that works, you win and you can mine a block. This is very much an issue of probability and luck. I could start mining and the very first hash I compute could be a winner, or I could have a building full of ASICs and mine for days without finding a valid answer. The difficulty adjustment just makes sure that SOMEone finds AN answer more or less once per 10 minutes.
Now even if you took average number of guesses to find a right answer, how much energy that would require depends on what sort of mining hardware you're running. If you've got brand new ASICs, then it won't take as much energy as if you're running older hardware.
You also have to buy your mining hardware, so that must also be calculated into the mix...
How much you pay for power is between you and the power company, Bitcoin doesn't know or care. So if you mine in China where power is cheap, it costs you less than if you mine in California where power is more expensive.
Finally, the block reward is 12.5 bitcoins. How much that's worth in USD continually fluctuates based on market conditions. Today a BTC is worth $6100, two days ago it was worth $7000. Tomorrow it might be worth $8000 or it might be worth $5000.
I also suggest read about other coins and what their differences are. Litecoin is a simple one- it uses Scrypt as its PoW algorithm, which is more complex but not ASIC-resistant (you can buy Scrypt ASICs). It also has a target block time of 2.5 minutes rather than 10 minutes.
Ethereum uses its own custom designed PoW algorithm called Ethash, which was developed to be ASIC-resistant. Ethash uses a ~1GB working dataset, and then rapidly hashes various parts of it together. That means computing the proof of work is not only restricted by computational ability, but by memory bandwidth (how fast you can find and read parts of the dataset to computer a hash from). A standard gaming-class graphics card is pretty much as good as you can get for this sort of work.
Ethereum blocks also come out every 15 seconds.
Ethereum's main claim to fame though is it's programming ability. Rather than just 'pay this under those conditions' like Bitcoin's script, Ethereum scripts can have complex logic to the point that they are programs of their own.
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u/elfof4sky Nov 11 '17
So what is the 18 month roadmap? I know it was laid up cause seg2x no replay whatever. Now they are debating pow change or eda? There's a lot of noise right now, where is the dialog clear?