Topic: Coins with very short block times demonstrate incompetence (Read 4773 times)

For all cryptocurrencies based off the Bitcoin protocol, the block time needs to be chosen carefully in order to guarantee that nearly every node in the distributed network maintains the same view of the blockchain.  The block time needs to be, at the very least, several times larger than the maximum end-to-end propagation delay across the distributed network.

Choosing a very short block time demonstrates a lack of understanding of this requirement.  If you make block times very short, then nodes will generate blocks faster than it would take for notifications to reach nodes on the opposite end of the distributed network.  This will cause nodes within the distributed network to have inconsistent views of the blockchain.

What does this mean?  1) Lots of orphans.  2) Very long orphan blockchains.  3) Significantly reduced security for the network.

Earlier today, one of the WorldCoin mining pools (http://wdc.dontmine.me) was on an orphan blockchain for more than 300 blocks.  That would never happen for any competently designed coin.

Altcoins with very short block times have no real future.  Once they reach a certain critical mass, they will inherently self-destruct due to the large percentage of inconsistency within the distributed network.  Imagine the blockchain accidentally forking into two separate blockchains.  With very short block times, that's a real possibility.  Or imagine having a transaction confirmed, only to realize hours later that the transaction was confirmed in an orphan blockchain and needs to be rolled back and reconfirmed.  No one would realistically support such an altcoin.

If you're going to release an altcoin, do the community a favor and at least release something that appears competently designed.

i think that less tahn 2 mins is a bad proposition.

Or are you just postulating that each halving of block time doubles the orphan rate?

It seems a bit too smooth to be realistic to me, miners presumably have a variety of connection speeds which should add some noise.

Do we have data on the orphan rates in LTC or Geist Geld and SmallChange which were mentioned earlier?

Of course a block time shorter than 10 minutes is perfectly viable! I never said that it wasn't. My point was that there exists a point where the orphan rate caused by a shorter block time ends up outweighing the benefits of a shorter block time. This starts to matter earlier than you may think because an orphan rate of just a few percent would be enough to encourage miners to centralize. However, ignoring that, here's an extrapolation of the reduction in effective hash rate as a network the size of Bitcoin reduces block time (the Bitcoin network currently sees about a 1% orphan rate):

Blocktime in seconds	Reduction in effective hashrate
600	1%
300	2%
150	4%
75	8%
37.5	16%
18.75	32%
9.375	64%

As you can see, two and a half minutes per block isn't actually all that bad in the reduction of effective hashrate, but I wouldn't want to go much lower than that.

This seems like mathematical nonsense, please prove to me that  for example if there are 4 times more chain splits with 1/4 the block time, that there are less iterations to arrive at consensus within the same duration. I bet you can't, because the increase in chain splits is trivial compared to the increase in blocks.

LTC has certainly proven for a long time that a shorter than 10min block target is perfectly viable.

Yes, but like most things in life, an important balance between too much and too little exists. Shorter block times make it harder for <50% attacks to succeed, true, but by increasing the number of orphans, it decreases the effective hash rate of the network, making a >50% attack potentially much easier. Bitcoin considers the potential risks of a successful >50% attack to be very high, so Satoshi chose a long block time.

GeistGeld has been humming along on 15 second blocks for what, years now?

So far the biggest problem was been the huge amount of RAM needed, more even than I0Coin.

I guess in a couple of years we will find out whether the RAM usage is due to the sheer number of blocks.

Or, we could update GeistGeld's code in case maybe it has a memory leak, as I0Coin is thought to have.

-MarkM-

Block chain fragmentation is not the issue, an overhead for sure, but it's the "double spend attack" from competing chains that we are worried about, which BTW doesn't means "51% attack". You can try to double spend with less but you may not be successful. The more blocks generated, the smaller your chance.  The probability of success with a <50% attack depends on the number of blocks and not the amount of time. This is an advantage of shorter block times.

GeistGeld has been humming along on 15 second blocks for what, years now?

So far the biggest problem was been the huge amount of RAM needed, more even than I0Coin.

I guess in a couple of years we will find out whether the RAM usage is due to the sheer number of blocks.

Or, we could update GeistGeld's code in case maybe it has a memory leak, as I0Coin is thought to have.

-MarkM-

If WorldCoin was meant to be an experiment of 'ultra-fast transactions', they should have tried a even lower block retarget time just for the hell of it.

15s has already been done several times, Geist Geld and SmallChange.

Anyway, it would be interesting to see something like satoshi DICE on 15s blocks 

That I am aware of, but hey, all of these coins are technically "experiments", so there's always time and room to do just that. Gotta start somewhere

Great retort. I assume you must be some type of middle school debate champ.

Cool story bro

That pool is really not that good. I was mining it for a while after launch, and I had constant disconnects. I wouldn't doubt the pool operator was doing something wrong.

I've been on Big Verns pool since then, and never had a problem.

Talk to me when this has happened on multiple, more reputable pools.

Block chain fragmentation is not the issue, an overhead for sure, but it's the "double spend attack" from competing chains that we are worried about, which BTW doesn't means "51% attack". You can try to double spend with less but you may not be successful. The more blocks generated, the smaller your chance.  The probability of success with a <50% attack depends on the number of blocks and not the amount of time. This is an advantage of shorter block times.