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Topic: Why 10 minutes? (Read 1227 times)

newbie
Activity: 52
Merit: 0
May 27, 2011, 11:27:11 PM
#4
Thanks to both of you.

That makes sense.
legendary
Activity: 1204
Merit: 1015
May 27, 2011, 11:09:15 PM
#3
Why a block every 10 minutes?

I'm sure this was discussed extensively when the protocol was first established and on this forum more than once, but I can't find anything on the reasoning.

On the surface, it seems to me if you are trying to create a global currency, then limiting any exchange of that currency to an average of once every 10 minutes seems like an artificial restriction on trade, and with some blocks I've seen a wait of over an hour until the the next.

I'm certain that it must have something to do with trust and preventing double-spending, but I would love to have that made more explicit.
Network latency. Honestly, I heard that it was just an arbitrary number that they picked.

What breaks if you aim for a block a minute and give the miner that found it 5 BTC instead of 50 for finding one, on average, every 10 minutes?
Probably nothing. However, the only speeds that matter are <5 seconds and >5 seconds because that would be a reasonable amount of time for a person to wait when they are checking out at a grocery store, for example. Any longer and the speed doesn't matter as long as it's less than a day. Since the network latency for other big p2p projects are around 30 seconds, that's as low as we could go. Thus, 10 minutes provides the best trade-offs between latency, speed, bandwidth, and storage.

Further reading:
http://forum.bitcoin.org/index.php?topic=4382.msg67351#msg67351
legendary
Activity: 1246
Merit: 1016
Strength in numbers
May 27, 2011, 10:59:52 PM
#2
There is a trade off between speed and wasted work from network latency. If you have a new block every minute and it takes 10 seconds to propagate the fact of a new block then ~16.6% of work miners do will be wasted. With ten minute blocks it's more like 1.6%.

edit: another way to say is that 16.6% of blocks found would end up orphaned because they were found after another valid block.
newbie
Activity: 52
Merit: 0
May 27, 2011, 10:49:28 PM
#1
Why a block every 10 minutes?

I'm sure this was discussed extensively when the protocol was first established and on this forum more than once, but I can't find anything on the reasoning.

On the surface, it seems to me if you are trying to create a global currency, then limiting any exchange of that currency to an average of once every 10 minutes seems like an artificial restriction on trade, and with some blocks I've seen a wait of over an hour until the the next.

I'm certain that it must have something to do with trust and preventing double-spending, but I would love to have that made more explicit.

What breaks if you aim for a block a minute and give the miner that found it 5 BTC instead of 50 for finding one, on average, every 10 minutes?

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