Is the 21 million bitcoin limit unchangeable?

[porcupine87]

Users aren't stupid though -- they know that fees are insufficient currently to incent enough miners to protect the network.    So adopting your fork would be crypto-currency suicide.        So the limit stays at 25 BTC per block, until block 420,000 and then 12.5 BTC per block, until block 630,000 and then 6.25 per block, etc.  

Now let's say it is year 2024 and fees alone are seen as being way more than sufficient enough to support the level of hashing necessary to protect the network, so the fear of the loss of subsidy impacting hashing capacity is not a limiting factor.   However, people who hold bitcoins include people who have lent their coins out to those who have borrowed bitcoins and need to repay loans (denominated in bitcoins).    

Good point with the incentive for the miners. But imo there would be enough miners without the subsidy as well. The ration between the fees and the estimated transaction volume (not the output volume!) is roughly 0,005% to 0,01%. You can easily reach 0,1%, what would be 100$ as reward for a block. So one year ago the subsidy wasn't more in termes of USD and there were miners.

Presumably anyone borrowing bitcoins would require a clause in the loan agreement that if the subsidy were to be reduced (change in the money supply were to occur) that their principal and/or interest would be adjusted appropriately.   If the subsidy is discontinued there would be little gain for those who have lent out their coins.  And who lends bitcoins?   The economic majority, that's who.  So it is not in the best interest of any of the economic majority to change the rules as far as the rate of Bitcoin issuance -- towards either direction up or down.

I can't follow. Let's assume the price for one BTC compared to real goods is stable, if there is an subsidy. Now I lend you 100 BTC for 5% interest. If the subsidy would be abolished the purchasing power of my 100 BTC would gain 2.5% every year and the interest rate drops to 2.5%. If I lend you the money it would be the same for me but it arises a new attractive option. Hording! 2.5% with absolutly no risk. So it is good possible that many bitcoin owner refuse to lend what raises interest rates again.

I think this topic is highly complex because we can't ignore that bitcoin is not the only possible medium for borrowers. Even the supply of bitcoins determinable because the velocity can always change. And the number of bitcoins? It will never reach the 21Mio. because every year bitcoins vanish forever (got lost, forgotten password, sent to orphaned address etc. but we will never know).

Finally, I do not exactly know who decides for the Bitcoin rules. Highly complex.


On the other hand borrower would not like bitcoins. Price inflation is always good for borrowers and bad for savers. Price deflation is the opposite. But this is highly complex. With less lenders and borrowers bitcoins might lose on purchasing power

[Stephen Gornick]

If the subsidy would be abolished the purchasing power of my 100 BTC would gain 2.5% every year and the interest rate drops to 2.5%.

Well nobody knows what the change to purchasing power is if this hypothetical "economic majority forces an immediate end to the block reward subsidy" and thus that 2.5% of currency inflation that was expected in year 2024 goes away.

That's why the buyer should require that lending contracts include some language that addresses changes in the protocol that would affect the currency inflation rate.   

But it is really a moot point, I believe.  The lending from the economic majority also includes loans to miners, and miners made an investment in their capacity counting on the subsidy -- it was part of the deal.  The miners would default on their loans causing once again for the economic majority a wash between the two options.   And that's a relatively minor issue compared to the bad image it would give.  If there were any alternatives a black eye like that would be a great catalyst to move to another one which is even more resistant to that type of corruption.

[batcoin]

It's also more than a bit rediculous to assume that future users would be running a full node, and could be tricked into supporting such a change simply by turning on an auto update feature.  First off, the vast majority of future bitcoin users, if bitcoin is ever truely succesful, will be running light clients or depending upon wallet service accounts; the full client will be the realtively rare animal.  Probably as many or more full nodes as presently exist, but still realtively rare overall.  Second, a group of end users, both stupid enough to trust their internal security with their money to a remotely controlled automated system AND wealthy enough to ignore the ongoing costs of running a full node would still amount to little, IMHO simply because there are now, and shall be, more than just the main reference client.  So whatever percentage is deceived into supporting the change will still be opposed (by default) by those nodes that do not authorize or otherwise cannot participate in an auto update.  Furthermore, the break wouldn't go unnoticed for very long, and a great many of the decieved users can and will revert.  

This is where our thoughts diverge. I don't think it's ridiculous to think that future users will be running full nodes. To an extent, I hope they do. Even with ASICs supposedly coming out to beef up hashing power 25-fold or whatever amount it's going to be - the total network is and still will be puny compared to the sum of computational hardware found in average homes where Bitcoin is currently seeing the most interest. It would be a matter of chump change to a certain number of governments or individuals to totally wreak havoc with Bitcoin as it now stands.

Chump change?  Is that so?


The bitcoin network is currently running at 460.28 PetaFLOPS according to bitcoinwatch.com.  According to Wikipedia, the fastest supercomputer on Earth is Titan, A XK7 model by Cray and installed at the Oak Ridge National Laboratory in Tennessee.  It has a benchmarked sustainable rating of 17.59 PetaFLOPS and an as-installed cost of $97 million. http://en.wikipedia.org/wiki/TOP500#Top_10_ranking) http://en.wikipedia.org/wiki/Titan_(supercomputer)

So to match wits with the Bitcoin network right now would cost at least $2.5 Billion.  And that presumes that the network doesn't grow before that monster is built!

Yes, that is so - even if the network grows beforehand.

http://en.wikipedia.org/wiki/List_of_companies_by_revenue
http://www.forbes.com/billionaires/list/
http://www.usgovernmentspending.com/current_spending

You linked an impressive computer, but it would be pretty stupid to try to build more of them to overwhelm Bitcoin when you could just use a few thousand, let's say 50,000 ASICs at at 25GH/s at $2000 a piece. (I use a higher price here to be generous to MoonShadow and a lower than average hash rate because governments don't tend to give much of a shit about value.) So we have a price tag of 100 million dollars to bring the network to 1.25 Exahash/s, which is roughly 33 times the size of today's ~38Thash/s. The Bitcoin ASIC industry is tiny at present with a relative handful of people involved. Do you think that TPTB would even bat an eyelash at spending 100 million (full retail price) to destabilize the Bitcoin network if it suited them? (As a side note, I think a small group of wealthy individuals would/could get involved too, but they would probably do it in a more economically feasible way.) I think Google would be a perfect example of a company already set up for such a venture. They have the capital and R&D to go into something like Bitcoin mining ASICs. And I think they could do it extremely quickly.

Another thing - FLOPS are a rough translation for hashes/s. The Bitcoin network technically runs at 0 FLOPS.
https://bitcointalk.org/index.php?topic=50720.msg605583#msg605583
http://bitcoin.stackexchange.com/questions/2917/how-fast-is-the-bitcoin-mining-network
https://bitcointalk.org/index.php?topic=99743.msg1091176#msg1091176

I am not trying to spread FUD, but simply bring these points to others' attention for consideration in this thread.

I think we need the individual users to have a full client running on their computers at home, even if they are doing something as minor as CPU/GPU mining or whatever it might come to be. I suspect that people will be able to just pop a small ASIC into one of their computer expansion slots in the future just to do their little part for the network even at a slight loss if it means adding resilience to the network. They can have their light clients running on their Huckleberry Pi-pads to do day to day transactions.

I don't doubt that this will be possible, but full clients won't be necessary for at-home reserve miners, they just need to join a mining pool.  Pool miners don't need full clients now.

This still leaves a problem of centralization, does it not?

The 21M limit is part of what makes Bitcoin what it is, if you don't like it or don't think it's going to work out, you can either support one of the alt-coins that suits your needs or start your own.  Just don't call it Bitcoin.

Where did I say I didn't like it or that I thought it wouldn't work out? I thought I was just discussing some points where Bitcoin could have some potential problems. Shouldn't we be discussing such things?

I don't think you have any idea how often I am sucked into these kinds of re-occuring newbie conversations.  Most of the old salts have long ago chosen to ignore such repetitive "problems".  The long and short of it is, it's not a problem, you're not the first to think it is a problem, so if you insist on resolving said problem there are numerous alt-coins that should fit your sensabilities better than Bitcoin.

Actually, I don't really care how many newbie conversations you've had. I neither asked nor forced you to respond to what I had to say. It was your choice to respond. I also don't think I made the claim that I was the first to think of something as a potential problem. I was just responding to a thread I thought was interesting. Please don't ascribe comments to me that I never made.

Seriously, newbs; read a bit before talking.  Should we increase the newbie surfing term before letting you guys out of the newbie section?

And aparerntly the post count into the thousands...

Come now... Really? This kind of response towards newbies having legitimate questions about Bitcoin really isn't going to help encourage people to get more involved in the project. I have been around these forums for awhile despite my low post count and late registration date. There is a lot of shit I don't understand on this site because I am not an expert in the given field. Once I feel I understand an idea, then I try to help out by putting it in my own words in the hopes of helping someone else out around here who may not understand some of the concepts on such a technical level.

[markm]

100 million, like hey, that is puny, less than a single bill for gosh sake!

We already know ten bills is pocket money because we just saw them reach into other people's pockets over just such an amount!

A few billion here, a few billion there, pretty soon you're looking at real money; a few hundred million here, a few hundred million there, that's a rounding error, isn't it?

-MarkM-

[johnyj]

I still have some question: What kind of loss were generated by the latest fork accident and how is it solved in the end?  As stated by BTCGUILD, they lost about 250 coin during the fork, and I think there will be some merchants affected by the invalid blocks of  that short lived 0.8 chain, how much are they and who has compensated for them?

It is a good chance to look at how many merchants actually use bitcoin network to do the transaction.  I doubt that 90% of the transaction is just miner's payment bumping around 

[johnyj]

Currently you can not reach that goal without a hard fork, and a hard fork as you have seen in recent event, is a very dangerous thing if not planned and handled very well

We already have reached that goal.  No fork required, because that was part of the original design.

Where is this conclusion come from?

If I remember correct, Gavin said that there is a consensus to raise the block size limit, I tends to agree that it is technically necessary

Before, I was very afraid of a hard fork, I thought it will be the end of bitcoin. But as the latest event showed, the community leaders have the ability to maneuver in a storm, so a planned hard fork might not be that dangerous

[markm]

http://www.quickmeme.com/meme/3teqcd/

-MarkM-

[batcoin]

100 million, like hey, that is puny, less than a single bill for gosh sake!

We already know ten bills is pocket money because we just saw them reach into other people's pockets over just such an amount!

A few billion here, a few billion there, pretty soon you're looking at real money; a few hundred million here, a few hundred million there, that's a rounding error, isn't it?

-MarkM-

It all depends on you look at it I suppose. Just knock a few zeros off and you can see it. Take Bill Gates for example. He has $67.00B. Do you really think someone in his position wouldn't spend $0.10B if he could turn it into a shitload more?

I am just trying to put some of this into perspective.

[MoonShadow]

Currently you can not reach that goal without a hard fork, and a hard fork as you have seen in recent event, is a very dangerous thing if not planned and handled very well

We already have reached that goal.  No fork required, because that was part of the original design.

Where is this conclusion come from?

From the part that you edited out...

With Bitcoin there is no reason we can't have both fast and easy transactions and a store of value at the same time.

Maybe that is possible, but don't be too greedy and reqire too much at a time

Currently you can not reach that goal without a hard fork, and a hard fork as you have seen in recent event, is a very dangerous thing if not planned and handled very well

Store of value was part of the original design.

If I remember correct, Gavin said that there is a consensus to raise the block size limit, I tends to agree that it is technically necessary

Before, I was very afraid of a hard fork, I thought it will be the end of bitcoin. But as the latest event showed, the community leaders have the ability to maneuver in a storm, so a planned hard fork might not be that dangerous

Not relevant.  We are talking about Bitcoin as a transaction system and a store of value.  The blocksize limit is a different issue.

[johnyj]

Not relevant.  We are talking about Bitcoin as a transaction system and a store of value.  The blocksize limit is a different issue.

Although different, it is closely related. To raise the blocksize limit, you have to do a hard fork, and a hard fork might affect "store of value" property of bitcoin

A hard fork means there is a change in bitcoin protocol, that will shake people's belief on many claims of bitcoin, just like OP wondered,  technically speak, all of bitcoin's claims can be changed with a client upgrade, then who is going to guarantee the consistency? This "Hard Currency" start to feel soft

If a hard fork will never happen, then "store of value" property will be intact. But this transaction system will become slow and expensive over time due to the block size limit, it might not be very practical to use bitcoin, when you need to wait for days/weeks for a confirmation (if you don't want to pay very high fee)

What is your view on this?

[johnyj]

Yes, I understand that now. I was under the impression that the coin limit was somehow fixed forever and could not be altered (like a transaction deep in the blockchain can't be changed anymore). But that's obviously not the case.

Great idea

Some basic rule can be fixed into genesis block, and each new client version must follow these rules. Unfortunately Satoshi did not make this happen, or it's already hidden in the genesis block? Maybe a hash of some string there is just 21M

[MoonShadow]

Not relevant.  We are talking about Bitcoin as a transaction system and a store of value.  The blocksize limit is a different issue.

Although different, it is closely related. To raise the blocksize limit, you have to do a hard fork, and a hard fork might affect "store of value" property of bitcoin

A hard fork means there is a change in bitcoin protocol, that will shake people's belief on many claims of bitcoin, just like OP wondered,  technically speak, all of bitcoin's claims can be changed with a client upgrade, then who is going to guarantee the consistency? This "Hard Currency" start to feel soft

If a hard fork will never happen, then "store of value" property will be intact. But this transaction system will become slow and expensive over time due to the block size limit, it might not be very practical to use bitcoin, when you need to wait for days/weeks for a confirmation (if you don't want to pay very high fee)

What is your view on this?

My view is that the association is silly.  The max_blocksize rule was added by Satoshi after the system was already running, in order to remove an attack vector via spamming of the transaction queue, until such time as a more elegant solution could be found.  It was never even intended to be a permanent rule.  The only reason that a "hard fork" might be required to raise or remove that rule is if some people don't agree that we should raise the limit.  Complete consensus is required to avoid a hard fork, and a hard fork is the last argument of otherwise independent bitcoin users.  Forcing a hard fork in order to alter some aspect of the network doesn't even mean that you'll succeed in altering your desired aspect, but the resources required to fight the good hard fork fight are quite high, and completely unrecoverable.  Yet, if a minority of users and miners decide to make that fight, there will be a blockchain fork, and the majority of the losses will fall upon the minority group until they can either muster up the resources to dominate the network or quit the fight and take their balls and go home.  So, theoretically, all that is needed to change the 21 M BTC limit is to get everyone to agree to that change; but that isn't something that is up for debate here.  No matter who or why, there is no way that a consensus to change that metric in Bitcoin is going to happen without a blockchain fork; and it would be a harsh fight.  That number isn't so arbitrary, unlike the max_blocksize rule.

[dooglus]

Yes, I understand that now. I was under the impression that the coin limit was somehow fixed forever and could not be altered (like a transaction deep in the blockchain can't be changed anymore). But that's obviously not the case.

Well, it's kind of the same.  The developers could declare that all blocks since block 27000 are invalid, and that miners must start working on a new block 27001.  If they did, we'd probably try to find new developers...

Similarly they could declare that they're increasing the number of bitcoins from 21 million to 42 million.  Again, hopefully the majority of bitcoin users wouldn't go along with such a scheme.

[Peter Todd]

My view is that the association is silly.  The max_blocksize rule was added by Satoshi after the system was already running, in order to remove an attack vector via spamming of the transaction queue, until such time as a more elegant solution could be found.

That's not quite true. Version 1.0 didn't have a 1MB limit, but instead used the same 0x2000000 byte, or 32MiB limit, used for any serialized data. Satoshi later added MAX_BLOCK_SIZE so that miners wouldn't create blocks bigger than 1MB, but larger was still accepted.

Finally the hard limit was reduced by Satoshi to 1MB in commit 172f006020965ae8763a0610845c051ed1e3b522 The commit comment is deliberately misleading: "only accept transactions sent by IP address if -allowreceivebyip is specified"

[MoonShadow]

My view is that the association is silly.  The max_blocksize rule was added by Satoshi after the system was already running, in order to remove an attack vector via spamming of the transaction queue, until such time as a more elegant solution could be found.

That's not quite true. Version 1.0 didn't have a 1MB limit, but instead used the same 0x2000000 byte, or 32MiB limit, used for any serialized data. Satoshi later added MAX_BLOCK_SIZE so that miners wouldn't create blocks bigger than 1MB, but larger was still accepted.

Finally the hard limit was reduced by Satoshi to 1MB in commit 172f006020965ae8763a0610845c051ed1e3b522 The commit comment is deliberately misleading: "only accept transactions sent by IP address if -allowreceivebyip is specified"

How was I "not quite true"?  Because I didn't bother to specify details?  Was I wrong about the reasons for the change?  The comment wasn't deliberately misleading, either.  There was a change to prevent direct to IP connections, as that had become viewed as a potential security risk.  If the comment was wrong, that was likely accidental.

[Peter Todd]

How was I "not quite true"?  Because I didn't bother to specify details?  Was I wrong about the reasons for the change?  The comment wasn't deliberately misleading, either.  There was a change to prevent direct to IP connections, as that had become viewed as a potential security risk.  If the comment was wrong, that was likely accidental.

It's not quite true because you're implying there wasn't a limit. There was a blocksize limit all along, it's just that Satoshi decided it should be reduced from 32MiB to 1MB.

Look at the early commit history of Bitcoin sometime; Satoshi made really misleading comments all the time hiding major changes.

[theymos]

Look at the early commit history of Bitcoin sometime; Satoshi made really misleading comments all the time hiding major changes.

True. In fact, he once asked me not to talk publicly about a new hard network rule he was adding (max sigops per block).

[johnyj]

How was I "not quite true"?  Because I didn't bother to specify details?  Was I wrong about the reasons for the change?  The comment wasn't deliberately misleading, either.  There was a change to prevent direct to IP connections, as that had become viewed as a potential security risk.  If the comment was wrong, that was likely accidental.

It's not quite true because you're implying there wasn't a limit. There was a blocksize limit all along, it's just that Satoshi decided it should be reduced from 32MiB to 1MB.

Look at the early commit history of Bitcoin sometime; Satoshi made really misleading comments all the time hiding major changes.

Maybe because he usually made several changes at each commit, or he just want to avoid confusing and panic at early stage of the development

[johnyj]

Yes, I understand that now. I was under the impression that the coin limit was somehow fixed forever and could not be altered (like a transaction deep in the blockchain can't be changed anymore). But that's obviously not the case.

This text is recorded in the coinbase of genesis block
"The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"

Related article
http://www.telegraph.co.uk/finance/newsbysector/banksandfinance/4092926/Second-bank-bailout-plans-condemned.html

This event was from England, so I guess that Satoshi is an english scholar. England has always been famous about so many great economists. Such a genius design of bitcoin is surely based on some deeper thoughts in macro economy

So in a worst case scenario where people have large disagreement with bitcoin's future direction, at least they will have a consensus that bitcoin will never take the same route as today's debt driven monetary system, since that is recorded in the genesis block

In fact, even the coin generation rate are changed in future, the bitcoin is still FUNDAMENTALLY different than today's debt driven money issurace: Each coin is debt free

This is maybe the hard-wired fact that OP is looking for

[johnyj]

My view is that the association is silly.  The max_blocksize rule was added by Satoshi after the system was already running, in order to remove an attack vector via spamming of the transaction queue, until such time as a more elegant solution could be found.  It was never even intended to be a permanent rule.  The only reason that a "hard fork" might be required to raise or remove that rule is if some people don't agree that we should raise the limit.  Complete consensus is required to avoid a hard fork, and a hard fork is the last argument of otherwise independent bitcoin users. 

Ok, I understand what you mean, I should not use "hard fork", non-backward-compatible client upgrade is the better description. You can have such kind of upgrade without causing a hard fork, if majority of users agreed

Forcing a hard fork in order to alter some aspect of the network doesn't even mean that you'll succeed in altering your desired aspect, but the resources required to fight the good hard fork fight are quite high, and completely unrecoverable.  Yet, if a minority of users and miners decide to make that fight, there will be a blockchain fork, and the majority of the losses will fall upon the minority group until they can either muster up the resources to dominate the network or quit the fight and take their balls and go home. 

It's not necessary to be a fight, two forks can co-exist since they serve the different interest from different users, its just those pre-fork coin can be spent on both fork, and it benefit the early adopters again (Pre-fork coins will worth more, people will try to get as much coin as possible before a fork happened  )

So, theoretically, all that is needed to change the 21 M BTC limit is to get everyone to agree to that change; but that isn't something that is up for debate here.  No matter who or why, there is no way that a consensus to change that metric in Bitcoin is going to happen without a blockchain fork; and it would be a harsh fight.  That number isn't so arbitrary, unlike the max_blocksize rule.

It does not matter it is MAX_BLOCK_SIZE or nSubsidy, as long as they can be changed through a software upgrade, there is a POSSIBILITY that a future software upgrade will change some bitcoin characters. This possibility is the biggest risk and uncertainty of bitcoin

I remember that Gavin said he worried about a fork when block reward drops from 50 to 25 coins last winter, since there was someone coded a client with 50 coins reward forever. But it seems that fork had some technical problems and was not able to maintain the stable block generation, so it ended without many people knowing of it