Topic: [Guide] Solo mine testnet bitcoins with cgminer, Bitcoin Core, and a Compac F (Read 1055 times)

Actually, I got maybe 6 or 7 'regular difficulty' (67.108.864 - only 30% lower than what it should probably be) blocks in just a couple of days now. I have to check the numbers, but it seems very unlikely to be this lucky this often.

I believe so, too. Even a CompacF takes just a fraction of a second.
Actually, one reason that might explain how I'm able to get almost every single 1-difficulty block is that 'regular' miners connect to a pool, meanwhile with nullama's method, we connect to our own full nodes. This should surely result in a smaller delay.

I'll run some numbers as soon as I can; likelihood of mining a 67M block (normal distribution), as well as ratio of 1-diff blocks I was able to scoop up vs. the total number in a given period of time.

There's no point in trying, if it's once in a million (or maybe billion). That means it will probably never happen, and that's what makes CPU mining futile.

At difficulty 1, getting the data from your pool may already take more time than an ASIC miner needs to find the next block.

Well, your gains will be always proportional to your power, in the long-term perspective. Which means, CPU-based miners will lose that battle very, very often, but once per N blocks, they could win. Or rather, to make it realistic: a pool of CPU miners could win.

Also, for that reason I left mining testnet3, and tried merged-mining with mainnet difficulty, but in a model, where each miner has its own difficulty, and is always rewarded every 10 minutes. Because one of the problems with testnet3 is that so much power is "wasted" into mining worthless coins. In that case, merged-mining fits better, because you can get coins that are almost worthless, but not quite. And you can easily test that kind of things inside LN, where normally you would have to pay, but if you are a miner, you can use your computing power as your currency. Also, because normally nodes don't want to pay you, what you can focus on is cheaper transactions: a node can give you some discount, or process some transactions for free, if you show your shares.

It is simple: if you have any mining power, then mathematically, you can always hit a block. Your blocks are as good as produced by any huge miner. So, instead of hitting some block every 10 minutes, you can hit it every day, every week, or even every month. But it also means, once per year you can hit three blocks in a row, or something like that. But then, you should not fall into gambler's fallacy, and think that you will hit the next block in the same day, if you were extremely lucky for a while.

It is not something you can fix. Your calculations are correct. But the very low probability, close to zero, does not mean that something will not happen. Even if you reach zero in your calculations, you could still encounter such situation in the real world.

There we go! Another block found, using the R909 actually. I like how it can quickly be set up without worrying about external fans and fine tuning any power settings. ^{[Review coming... soonTM?]}

Sadly the block reward is quickly dwindling in Testnet already.. +0.044tBTC this time.

Edit: Another one, an hour later! +‎0.02996310 tBTC
Edit 2: I got the immediately following block, too, at full difficulty.

With my previous calculations, that is very unlikely. I have 1.7TH/s, so:

I'm basically expecting to need 2 days to mine a block at this difficulty, but did it in 3 minutes. Pretty neat.

Edit 3: I found another difficulty=1 block, as well as another at 67108864. How is that possible? I need to double-check my calculations...

Not at the current difficulty. People are mining blocks every 2 minutes; there is realistically no chance for a 20 min time period without blocks.

I know, that's what this whole thread is about and I've been scooping up tons of 1-difficulty blocks months ago, myself!

That is not true; LoyceV has shown it in an experiment and we've calculated it on paper, too. ASICs solve these blocks in a fraction of a second, meanwhile a (regular / not highest-end) CPU can need minutes or more; no advantage in internet speed will be enough to offset that.

That's incorrect.

Despite being worthless, people are still mining testnet. So I expect at least some of them to continue mining when there's no block reward left. That also means total fees can be under the dust limit. And even if they don't, with low difficulty just one miner is enough to continue the chain. We may see 1000 block 99% attacks once in a while.

Testnet coins already seem to be quite scarce, my guess is many are lost. After all, there's not much of a reason to be careful with worthless coins. That means testing in the future will have to happen with smaller and smaller amounts.

For that reason, it is very unlikely that testnet3 will ever be killed. Because now, it is the only network that is quite close to mainnet, and where you can test, what will happen when the basic block reward will be very small. It is also probably the first network, that will reach zero block reward, and then a lot of people will carefully observe, what will happen next.

By the way, testnet coins are worthless by definition. So, if nothing else will happen, then testnet3 will finally reach a state, where the basic block reward will truly represent the real value of those coins. In general, testnet3 could have zero supply, but some coins are needed as a spam protection.

Well, if you use other test networks, then you can easily get much more coins. But as far as I know, testnet3 is the only truly decentralized test network, that we currently have. Signet is centralized, because of signet challenge. Regtest is centralized, because you can create a blockstorm on CPU, so it cannot be used online. So, for better or worse, we are left with testnet3, because only in this network you can test everything, including mining. But of course, it could be improved, and some improvements were proposed, so we will see, how it will evolve.

You can always have some 20-minute block with the minimal difficulty. After 20 minutes, there are two options:
1. Some block with difficulty one will be accepted.
2. Some block with the real difficulty will be accepted.
And even if you cannot produce some strong block, there is always a chance to produce some weak block. It can be reorged or not, it depends if someone will try to attack, and if you will be well-connected or not. Because when it comes to weak blocks, everyone can produce them, by using CPU, GPU, FPGA, ASIC or whatever. So, in that case, the winner is the one who will spread it faster to the rest of the network, and who will not be reorged. In those cases, CPUs are more important than other hardware, because they are used to send blocks, so it is a competition between nodes, and not between miners.

Oh wow, that makes total sense! I never thought about that. Very interesting. It doesn't sound intended; more like a bug that should be fixed. On the other hand, I feel like nobody really cares too much about Testnet.

Edit: Since this happened before, I guess there will be no changes made!

I'm aware of this, yes. There were even discussions about it here on Bitcointalk a while back..

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Unfortunately, for now this means we won't have 20-minute block times in a while, i.e. no solo-mined tBTC. As the base difficulty has already exceeded 16M a few days ago. I expect it to take about 2-3 more epochs to reach normal levels again.

It came from several blocks per second, see Interesting behaivor of TESTNET difficulty.

This caused it:

And this made it last:

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Note that there's not much left to mine on testnet: the block reward is now 0.024, about 300 times lower than Bitcoin mainnet.

Today I noticed something weird on the Testnet blockchain. We are getting blocks about every 2 minutes; difficulty is way too low. According to https://mempool.space/testnet, the difficulty was already raised in the last difficulty adjustment and it will be raised again today by 300%.

Was there a huge dip of hashpower a few weeks or months ago that tanked the difficulty or did someone point an enormous amount of miners to Testnet recently?

When a stale block is mined, it is not included in the longest version of the blockchain, and is therefore not valid.

Basically this can be due to network problems, by the time you distribute your block and it is spread among enough nodes, it may have been overtaken by another block or become invalid in the meantime. That's why when you mine solo it's very important to have the lowest possible network latency (we often say less than 100ms with the solo pool to be ok)

Please note that even if you see a reward for a stale block, you will never be able to spend it because the coins will be invalid. If I'm not mistaken, the coins are returned to the mempool
Fortunately most of the pools have a low rate of orphan and stale blocks, another problem is that the big pools accept to mine empty blocks without transaction, which is anything but good for the BTC network...

so you have a block with only coinbase transaction. what can make it stalled after 5 seconds? and what means stalled? yeah for educational purpose it would be not bad to make it splitted from broadcast unit. It can be done like in openssl ( openssl.exe ) where you can make stand-alone utils instead

What transaction? You want to write a miner which doesn't automatically submit a new block to the blockchain, but requires you to do it manually? That would be hilarious. You would mine so many stale blocks. I mean, a correct block at difficulty 1 will be stale in a matter of seconds, if not less. My ASIC alone, generates around 100 valid blocks per second as soon as the difficulty drops.

Furthermore, while you can submit raw transactions with some wallets, you cannot submit blocks without running Bitcoin Core.

Thanks all for your kind help and support.
I tried cmmodtools and got the same errors, then I tried phaenomenon. Same errors. Then finally I tried vthoang and it compiled perfectly. I couldn't figure what was causing the error.

i think you'd overcomplicated it really. it could be 400 lines cpp single file( with 50 lines go to simd switch/case) where you broadcast tx later yourself with a wallet.

As mentioned earlier, you're not sharing here the full log of errors, so it's hard to help with what you posted only.

And based on what you did post, it looks like you're not following the instructions exactly, as it seems like you're using a different repository (cgminer_phaenomenon instead of cmmodtools).

So, first, try following the guide correctly(instead of doing it wrong multiple times), and then if that doesn't work for you, post detailed logs.

The part of the log output showing the actual issue is missing. You can post the whole log in a code block here or if you feel unsure if there is any PII in it, send it to me via DM.

Hi,

I cannot install the cgminer on my Ubuntu 20.04.5 LTS. I keep on getting this error message:

make[2]: *** [Makefile:999: cgminer-cgminer.o] Error 1
make[2]: Leaving directory '/home/user/bitcoin_testnet/cgminer_phaenomenon'
make[1]: *** [Makefile:1894: all-recursive] Error 1
make[1]: Leaving directory '/home/user/bitcoin_testnet/cgminer_phaenomenon'
make: *** [Makefile:808: all] Error 2

I have installed and updated all the libraries and tried to do the whole process over and over but I get the same end result.

Any thoughts on this issue?

As far as I could see, I never mined a block.

I assume that's not a problem, Linux multitasking should be able to handle this. And I used nice for the miner.

Thanks! I'll PM you the details (and let's switch back to the correct thread).

Usually in parallel programming (multi-thread) when one thread finds the answer it breaks out of it and sends a "signal" to other threads to break too. Which means after finding the new block at least part of CPU has to be freed to be used for the broadcasting process.