Topic: Need large amount of testnet bitcoin, can someone help me? - page 2. (Read 863 times)

Hi, sorry for the late response.
I  would like to build a crypto exchange and a mixer.
And just like you say. I need enough coins to test stability.
I think I can give the collateral, but not sure what is it...
Please tell me the detail, thanks.

Soooo.... to get a lot of testnet coins, just run a bunch of asics, or wait for diff to drop to 1 and then run the asics. But that's what everyone with an ASIC miner will do. I guess just keep it on for awhile, eventually you'll get at least a few blocks in when difficulty drops to 1.

You'd need to rent hashrate for a much longer time period if you don't own the mining hardware, whereas anyone with previous generation miners would be able to get something in.

7 halvings ... maybe testnet should be reset again and block rewards not get half, .. or maybe .. well, then how do we test the future, LOL.. id' like to see what happens in testnet if it's like the year 2140 or something equivalent (but only people with current day hardware can mine) where block reward is just transaction fees.

Or something like after every 2 or 3 halvings, it goes back up to 50 per block.

Alternatively, one can just use an altcoin or make your own fork, since it's for testing purposes. You'll get as many whole coins as you need. But, yeah, it's an altcoin ... (go fork and make Bitcoin Test Fork ABC XYZ BSV Gold Platinum Diamond Need It for Mixing Something...)

^^ This ^^ is correct

It's a tad bit more elaborate tough...
If a block hasn't been found for 20 minutes, the diff indeed drops to 1.

Now, let's assume we've just had a diff adjustment at height x
at height x + 1980, the guy running a couple of ASIC's on the testnet decides to turn them off, block @ height x + 1981 isn't found for 20 minutes (diff = 1), block @ height x + 1982 idem...

Now, when we finally arrivate at x + 2016, the average time between 2 blocks > 10 min and the current diff is 1....
Sooooo... At the retarget, the diff will once again be 1 (the minimum), but it'll stay 1 for the next 2016 blocks.
After another 2016 blocks, the average time between 2 blocks is just mere seconds, so the diff is adjusted to 2.
After another 2016 blocks, the average time between 2 blocks is just mere seconds, so the diff is adjusted to 4.
After another 2016 blocks, the average time between 2 blocks is just mere seconds, so the diff is adjusted to 8.

Sooo, in this case, if the ASIC guy turned his ASIC's off @ height x + 1982, and turned them back on @ x + 2017, he'd be able to mine thousands and thousands of blocks in MINUTES... It would take a ton of retargets before the diff was adjusted to a height that would bring the average time between 2 blocks to ~10 minutes.

However, since he's the ASIC guy, he'd still be able to mine most of the blocks compared to a CPU miner.

Let's say the ASIC miner only has 5 Th of hashrate, while a cpu miner has 5 Mh => the ASIC guy produces a whopping 1000000 times more hashes per second than the CPU guy, so the odds of him finding a block at diff 1 is 1.000.000 times higher... Offcourse, at this point, things like other factors come into play (network speed, network hashrate, which nodes you're connected to, time needed to verify a block, IO ,...) but still...

There are indeed a couple of working testnet faucets. (I used to google for them.) But the amounts they give are usually small. You'll need a huge effort to gather big amounts like the 50 tBTC OP was asking.
I find mocacinno's offer reasonable. Basically OP would only lose the tx fees for the collateral, since he will return the loaned tBTC (and if any tBTC is lost for fees, that can be recovered from faucets).

Wait i dont get it. I thought there are some online site which is even mention on bitcoin.org site and on this forum for getting the testnet bitcoin for free, i mean site like
https://tpfaucet.appspot.com/
https://bitcointalksearch.org/topic/bitcoin-bitcoin-cash-groestlcoin-testnet-faucet-coinfauceteu-950331

Are the site not working again?

I don't follow Bitcoin's testnet closely, but I assume it's because the difficulty drops back to 1 whenever no block has been found for 20 minutes [1]? At least that would explain testnet's block height of beyond 1.6M [2] which means it already went through 7 halvings which would correspond with the block subsidy mocacinno mentioned.

[1] https://en.bitcoin.it/wiki/Testnet
[2] https://live.blockcypher.com/btc-testnet/

I understand completely. I wonder why the block reward is so small though, shouldn't it match mainnet, more or less.

This just means there are people mining something worthless. Or, mining not for profit, since one does not sell testnet coins.

It's much "cheaper" to just run the faucets every day to get more coins than you can mining with a single S9. That's so strange to me, but I wouldn't know, I don't hang around the testnet often. I have some on a Lightning wallet, but I also got those from a faucet. So I "test" them by buying starblocks or something like that.

Seriously, what could the rational be for the mining difficulty to be so high, or does it simply not cost some rich miner to unleash a few machines on the testnet ... maybe they are old equipment running on solar or something.

That's true, they don't have any value... But that doesn't mean you can mine them for free anymore...

I would give a tBTC loan to anybody who wants one, but for people i don't know i still request collateral so i get the tBTC back and i don't have to rent hashrate to mine new tBTC for my faucet out of my own pocket.

I know it kind of defeats the purpose, and i really wonder why there are people that insist on pushing the difficulty on the testnet so incredibly high by mining on the testnet with relatively new ASIC's... I'd love to mine on the testnet with my cpu, but if i did this i'd mine close to nothing  

I did a VERY raw calculation, based on prices i found on miningrigrentals:
You can rent an S9 with 16,5 Th hashrate for  0.00002/hour.
The diff is 10.5M
The block reward is 0.39 tBTC

So, if you run this S9 for a full day, it would mine:
 (((((16500000000000 * 0.39 * 600 * 65535) / 2^48) / 10500000) * 6 * 24) = 12.3 tBTC/day

A day of mining with this rented S9 would cost 0.00002 * 24 = 0.00048

So, mining 1 tBTC with rented hashrate would cost ~0.00004 BTC, NOT including the transaction fees, not including the fact that you'd end up with change on miningrigrentals, not including the time i'd need to setup everything, not paying for my efforts, not including the odds that i'm unlucky and hit less blocks than average,...

testnet BTC are not supposed to have any value ... ... but ... yeah.

What and why you are going to mine? And why you are asking to people to donate something to you? What are the benefits if I am going to do this?

Nope, you either run in regtest mode, or you mine tBTC...

Sometimes 0.5 tBTC does not suffice, for example: if you're designing a mixer... You'll need a lot of tBTC in order to do a proper taint analysis.

@OP: I run a faucet: https://tbtc.mocacinno.com and i've given tBTC as a loan in the past. I have > 50 tBTC (but most are on my hardware wallet at home, so i can't access them for another 3 hours)
However : since you're a newbie, i would require sufficient collateral for such a loan. The collateral should be sufficient to rent hashrate from miningrigrentals and mine >50 tBTC in case your run off.
To tell you the truth, the diff on the testnet is still very high and the block reward is ~0.39 tBTC, so i'm afraid it'll be a lot of collateral to loan 50 tBTC.

IF you're interested: i'm willing to use a trusted forum escrow to hold the collateral, no intrest, but ALL fees are payed by you (including the fees to transfer the collateral to me or the escrow, and the fees to transfer the collateral back to you). Please do not PM me, but post anything on this very thread... I don't like to hide in PM's, telegram, mails,...

What would you need 50 testnet coins for, that 0.50 or 0.05, or 0.005 will not suffice? I don't have that much either, but you can always get from the many faucets a small amount. It's for testing, the amount should not matter.

But I'd like to also know if there are any other ways of acquiring such amount of testnet coins other than mining them.

I would appreciate any contribution but the experiment will take almost 50 testnet BTC.
It will obviously not be destroying those coins so if you would like I could return it to you or to a faucet of your choice.

The address is mk8NxMJEPE8F1K2o9Z3QzJLQbnPHdML9mn. Let me know if you've any questions.

Thank you.