EVERY transaction in blcok chain? Flaw?

wareen

legendary

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Revolutionizing Brokerage of Personal Data

Quote from: doobadoo on May 19, 2011, 07:57:26 PM

Isn't the size of a block the legacy of all the transaction of those 50 btc?

I think here lies another misunderstanding: a block can contain transactions worth much more than 50 BTC. The 50 BTC are only the current reward for the first miner finding a suitable hash for this block. One block has currently a size limit for the total amount of data describing the transactions - no limit on how much BTC can be moved within one block.

Maybe you should have a look at the blockexplorer to get a better understanding of what a block looks like and what it contains.

chickenado

hero member

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Here's a thought for you:

The amount of data stored in the block chain grows linearly (once the user base has stabilized).

The capacity of the internet to transmit, store, and process data grows exponentially.

In the long run, we're gonna be just fine.

Garrett Burgwardt

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Quote from: doobadoo on May 19, 2011, 07:57:26 PM

I still don't quite get it. How is there a 1 MB limit on the size of a block chain..?
Isn't the size of a block the legacy of all the transaction of those 50 btc? With pool mining there could be thousands of original owners and then thousands upon thousands over the years... I think i'm not understanding something. Couldn't we get a block with tx history greater than 1 MB.

Ah, there's your misunderstanding. Each block doesn't have a complete history of the coins involved in those transactions, just the new transaction and a pointer to say "here's where I got that coin from", which is checked. The transactions just build off each other, but don't grow like you think they do.

just_someguy

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Quote from: doobadoo on May 19, 2011, 07:57:26 PM

I still don't quite get it. How is there a 1 MB limit on the size of a block chain..?
Isn't the size of a block the legacy of all the transaction of those 50 btc? With pool mining there could be thousands of original owners and then thousands upon thousands over the years... I think i'm not understanding something. Couldn't we get a block with tx history greater than 1 MB.

The 1MB limit is an arbitrary limit that will eventually be removed. Thats just for the block... the collection of transactions that is created ("mined") on average every 10 minutes. If you maxed out the current 1MB limit the block chain would grow ~6 MB an hour.
The limit would be removed long before this happens.

No matter how large the block chain grows a non-miner can operate with just the 80 byte block headers. This means no matter how many transactions occur you would only need ~4.5 megabytes of storage at most. Realistically you could start tossing old headers with check points and get it down to much lower.

JohnDoe

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Quote from: doobadoo on May 19, 2011, 07:57:26 PM

I still don't quite get it. How is there a 1 MB limit on the size of a block chain..?
Isn't the size of a block the legacy of all the transaction of those 50 btc? With pool mining there could be thousands of original owners and then thousands upon thousands over the years... I think i'm not understanding something. Couldn't we get a block with tx history greater than 1 MB.

Blocks are not tied to particular coins, they only store the transactions that have happened since the last block.

MoonShadow

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Quote from: doobadoo on May 19, 2011, 06:54:14 PM

Obviously all we need to KNOW are just who the CURRENT legitimate owners of that original 50 BTC block, but even that may be some day thousands of entries long as the BTC subdivides into ever smaller units.

Is this basically it or am i still not getting it...

Um, no. I think that you aren't quite getting it. There is no owner for the block, the block isn't traded. There really isn't any object that can be called a coin, not even a digital object. The blockchain is a massive, collective ledger system. The blockchain tracks addresses by recording the transactions that grant and remove bitcoins from them. A complete blockchain has all of the transactions that have ever been recorded, but it can be pruned of transactions that have already had their values spent again by their owners, after those new transactions are old enough to know for certain that they will not be reversed. This is the purpose of the 'merkel' hash tree that defines the structure of a block, so that spent transactions can be deleted from the block without breaking the validity checks that new clients must perform on the blockchain upon bootstrapping. The blockchain will eventually grow to a massive dataset, but not nearly as fast as if every division of the coins required that the block itself be duplicated and signed again.

doobadoo

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I still don't quite get it. How is there a 1 MB limit on the size of a block chain..?
Isn't the size of a block the legacy of all the transaction of those 50 btc? With pool mining there could be thousands of original owners and then thousands upon thousands over the years... I think i'm not understanding something. Couldn't we get a block with tx history greater than 1 MB.

JohnDoe

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Activity: 392

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To put it in perspective, if every new block reached the current limit of 1 MB for a year it would add 51 GB to the block chain. Meanwhile, there are 3 TB disks going for $150. And as it has already been said, it is not required that everyone stores the block chain.

xf2_org

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We can prune spent TX's from the block chain... that is fully baked into the design.

FreeMoney

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Strength in numbers

Quote from: doobadoo on May 19, 2011, 06:54:14 PM

Wow, what great answers...

Okay, so the downloading all the blocks thing that happens when i first install the client, that currently has all the transactions. When i say ALL i mean lets say that last year 50 BTC block was cracked and moved into circulation when the miner tipped it out to say 100 diff people. THose people went ahead and spent it in different places etc...this block now 1 year old could have thousands upon thousands of transactions now for the WHOLE history of movements between all addresses.

Obviously all we need to KNOW are just who the CURRENT legitimate owners of that original 50 BTC block, but even that may be some day thousands of entries long as the BTC subdivides into ever smaller units.

Is this basically it or am i still not getting it...

I think you've got it.

doobadoo

sr. member

Activity: 364

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Wow, what great answers...

Okay, so the downloading all the blocks thing that happens when i first install the client, that currently has all the transactions. When i say ALL i mean lets say that last year 50 BTC block was cracked and moved into circulation when the miner tipped it out to say 100 diff people. THose people went ahead and spent it in different places etc...this block now 1 year old could have thousands upon thousands of transactions now for the WHOLE history of movements between all addresses.

Obviously all we need to KNOW are just who the CURRENT legitimate owners of that original 50 BTC block, but even that may be some day thousands of entries long as the BTC subdivides into ever smaller units.

Is this basically it or am i still not getting it...

jimbobway

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Read this:

https://en.bitcoin.it/wiki/Scalability

If you read satoshi's paper it will describe a system to validate a transaction without having to download the blocks. This is implemented in BitcoinJ, the android implementation. Look for "Simplified Payment Verification".

FreeMoney

legendary

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Strength in numbers

Quote from: doobadoo on May 19, 2011, 06:39:27 PM

Lemme take a whack at this again:

Each block represents 50BTC right? Okay, but the ownership record of that BTC gets longer and longer as it and pieces of it are traded around. How is that not a recipe for eventual destruction...it makes no sense to me. some one help.

Yes, it gets longer over time, it will be handled. There is math stuff that can reduce it to what is needed to process tx. If you are not a miner you can run a simpler version (which doesn't exist yet) that lets you safely watch for new tx without having all the old ones. If you are just a really casual user you don't need anything, you can just use an online wallet. There is even a web wallet in development that won't know your keys.

Garrett Burgwardt

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Yes the blockchain will become very large.

No, you don't need all of it. And you can trim what you do need down further.

Miners are the only ones who need the entire blockchain, and hard drives are trivially cheap.

doobadoo

sr. member

Activity: 364

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Lemme take a whack at this again:

Each block represents 50BTC right? Okay, but the ownership record of that BTC gets longer and longer as it and pieces of it are traded around. How is that not a recipe for eventual destruction...it makes no sense to me. some one help.

Garrett Burgwardt

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Activity: 406

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No. Not only is computational power trivial in regard to verifying a tx, but headers only mode means that the average joe can run bitcoin easily too.

doobadoo

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i am reading the wiki and myths...i really just don't get it.

every transaction, that is movement of funds from one address to another (which is all that is communally know right?) That file ultimately grows in size with respect to new transactions... Eventually won't this file overwhelm the ability of clients to operate in real time?

FreeMoney

legendary

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Strength in numbers

Every transaction that is needed will be maintained by anyone who needs that info (miners mainly). It will scale fine and there is info about this all over. Check the wiki, scalability.

doobadoo

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From the FAQ:

"The block chain is a neverending story of every transaction throughout the network from day 1 (genesis). The first time you run Bitcoin, it is downloaded and verified on your computer. Every new transaction is added to the end of this chain and verified by the network to be valid. "

Isn't this BTC's fatal flaw? If this were to take off in popularity, all the new transactions would start to make this "block chain" file huge and unwieldy... Can any one explain why this is not so. Surely this has been addressed. As a person who's worked in the securities and banking sector, i've seen some pretty massive transactions databases. If BTC is to have a real run, this sucker has GOT to scale to handle billions of transactions per day. How long will these block chains get?

Topic: EVERY transaction in blcok chain? Flaw? (Read 1886 times)