Bitcoin Forum

This has probably been discussed a lot of times, but I just can't find the right answer.

What is the estimated date that the block reward changes to 25 BTC?

From the Wiki (https://en.bitcoin.it/wiki/FAQ):

The coin value of a block is 50 BTC for each of the first 210,000 blocks, 25 BTC for the next 210,000 blocks, then 12.5 BTC, 6.25 BTC and so on.

40515 blocks to go at 6 block per hour makes it 281.4 days, so on 9th of december 2012.

Thanks guys.

I too want date for 25 btc

You too can read this thread.

There is no exact date because it is based on # of blocks and while on average blocks will take 10 minutes each there is no exact correlation between blocks and time.

It is roughly Dec 9th as indicated above.  As we get closer to December the date will have less variance.

Place your bets:

December 9th or earlier the bitcoin block reward will drop to 25 BTC
 - http://betsofbitco.in/item?id=312

Personally, I'm stumped.  I do think the marginal GPU miners (e.g., where electricity is expensive, or not much capacity) will see the 25 BTC drop coming up and some will sell off their hardware to prior to this date.  (meaning capacity drops and the date comes after December 9th.)  On the other hand, FPGA miners by then could be plentiful (which would cause capacity to increase, and the date come before December 9th).   Also, if the BTC/USD heads higher the date before December 9th becomes more likely as more capacity gets added.   Who knows.

Heh.  When I first read this, I thought that you were very lonely, if you were willing to pay 25 BTC for a date.  I didn't grok your question until I read the next reply.

Here's a guess:

9th Dec assumes current rate continues.

I expect bitcoin price to increase (on average) throughout the year.  Higher price equals more miners.  A steadily increasing number of miners means that each block is found slightly faster than anticipated, and that continues for 2016 blocks before the difficulty compensates.  Except that the next 2016 blocks have the same: an increasing number of miners.

In short: block rate will average faster than one every ten minutes.  Let's guess at 9 minutes between blocks.  That's 10% faster.  Instead of 281 days, it'll be 252 days ish.

In other words: about a month earlier.

My guess would therefore be 10th November.  But on the chance of there being historical coincidence I'd like to choose...

"remember, remember, the 5th of November."

 :)

 The Mayan's estimated the date correctly

Der de dum dum

blocks produce at the same rate with difficulty adjustments. It will vary a little because of the lag behind each adjustment so it will vary a little bit but probably not alot. The mayans did get it right....... lord help us all......

I'm thinking along the same lines, but don't think the impact will be that large. I'm guessing around Dec. 5th, placed my bet accordingly.

I agree with above post that high-electricity-cost miners will anticipate the problem and stop mining, but I think that also traders will anticipate the "drop in supply" as they will call it and that will raise the price in anticipation making mining more profitable again.

This is one example of the feedback loops in this whole shebang. It will be highly interesting to observe and it will likely take effect pretty early, like in late summer.

I think in the end, not much will change, at least not much more than usual ;)

While that is true I think there are two counterpoints.

First is that price to difficulty is relatively low right now.

http://bitcoinx.com/charts/chart_large_lin_90d.png

So while price may rise (say to $6 or even $7) I wouldn't expect to see large increases in hashing power.  We really would only be getting into more sustainable price/difficulty ratios.

The second is timing.  Yeah if BTC went to $10 tomorrow you would see a large increase in hashing power and that trend would continue for 3 or 4 difficulty intervals.  However if BTC hits $10 in say late October any new hashing power has to be thinking of the fact that price/difficulty (the only metric that matters to a smart miner) is going down by 50% in a month or two.  The close we get to the date the more of a factor that will be in NOT deploying new hashing power.  Smart miners will take a "wait and see" attitude.

My guess is we will hit the drop earlier than 9 DEC but I don't think it will be by much (maybe 5-10 days).

Let's bet on this over on

http://betsofbitco.in/item?id=313

Back your statement by money and have some excitement :)

-coinft

why not bet on the bet published earlier in this thread: http://betsofbitco.in/item?id=312

I am surprised BofB allowed such a similar bet.  Spreading the action around is never good.

Yes someone was faster than me. Notice I have the following id. Bet on the first one, mine was canceled as duplicate.

-coinft

Update on that calculation since we are exactly nine months from the target date on the bet:
 - http://betsofbitco.in/item?id=312

With block height of 170,390 reached, doing the math that gives us 275 days left, so still on target for December 9th as the day block 210,000 will be reached.

What is certain is that the number of bitcoins issued each day will be cut in half.  Meaning if miners are generating $36K worth of bitcoins on December 8th, then the drop occurs, then starting on December 9th they will generate $18K worth of bitcoins -- though there would be some fluctuations in price that might cause those numbers to vary but essentially it will be a sudden 50%-ish drop in revenue.

We know today within a window of a couple weeks when that event will happen.  We also know miners who pay for electricity won't mine at a loss for very long.   We also know many miners have no other use for the GPUs.

A rational miner might consider selling off those GPUs before there is a glut on the market (though prices have dropped for used GPUs, prices currently are pretty decent -- compared to the discount other electronics see when being sold as used.)  A rational miner might also look at the emergence of FPGAs in mining combined with this 50 BTC -> 25 BTC block reward drop, see the writing on the wall, and start taking action now.

Which would cause a rational speculator (if there are any) to suspect that difficulty will not continue rising and instead will start dropping again as the result of miners shutting down, and thus the date occurring later than December 9th.

But then we have history.  When difficulty goes up, it tends to do so in bursts -- 8%, 15% or higher even.  When it drops, it does so gradually.  Which would mean even if we reach block 210,000 and the difficulty is no higher or lower than the level it is at today, we'll get there sooner than December 9th because the bursts had a bigger impact on calendar time than the drops did.

I still have no leaning as to which outcome is more likely.  Tell me what the exchange rate will be and the number of FPGA units that will be sold over the next half year and the difficulty level at a future date becomes easier to predict.

Sorry about the confusion guys. It was our fault and fixed. #312 is the one to bet. Let me know if you have any issues.

You mean your average date costs less than 25BTC? Cheapskate :P

Assuming all mined coins are immediately sold on the market, there would also be a sudden drop of "supply" on the exchange markets. A sudden 50% drop of supply given constant demand would surely drive the price up quite a bit. Of course the market will react even before the fact in anticipation, driving price up, in turn making mining more profitable again even before the drop.

So my argument is that the 50% drop in mining income (measured in BTC) will not result in a 50% drop in USD-denominated revenue for this reason (higher price)

Also miners are likely to reduce the percentage of BTC they throw directly onto the markets, but hold on to them (or a part of them) in anticipation of being able to sell at a better price after the supply drop. So this is another factor that puts upward pressure on the price before the fact.

I actually think there might not be that much happening on the date. Most of the action and adjustments will be happening beforehand in anticipation, starting in late summer, maybe even earlier. I, for one, am already holding on to my bitcoins a lot harder ;)


Well, the exchange rate is part of the game, so you must include that in your set of values to predict ;)

I'm leaning towards an earlier date because I'm assuming an increasingly bullish market toward block 210000 which will result in mining power increase.

As for miners selling their hardware: I kind of doubt they will do that in the 1-2 months before the drop. They might sell now or in early summer, but after that, it's just too tempting to keep things running at least until the drop. Most rigs are probably payed off anyways and gaming is always an option ;)

The moves in the chart over the past days don't appear they can easily be explained as variance.  

Previously Bitcoin hadn't seen the situation where the exchange rate was stable but the but mining difficulty swung one way or another to this degree -- and not like this -- huge dip followed immediately by a huge spike.  Something's coming down the pike.

FPGAs are attractive due to lower power required -- the megahash/Joule (Mhash/J) is an order of magnitude greater than that with ATI GPUs:
 - https://en.bitcoin.it/wiki/Mining_hardware_comparison#FPGA_Devices

Maybe production of FPGAs is going to start having a significant impact on the difficulty?

That would push the date to occcur earlier than December 9th.

https://i.imgur.com/6vjnE.png (http://bitcoin.sipa.be/growth-10k.png)

 - http://bitcoin.sipa.be/growth-10k.png

Fix'd that for you.

The red line and the green line are noise.  Even the blue line is sketchy.

wonders wth people did not look at this before posting rants.

I guess ignorance has it's place.......

Just an update:

The hash rate increased 8.56% this last block adjustment period, which took 12.9 days instead of the targeted 14 days.
 - http://bit.ly/vFZwdF

That pulls the date earlier.

The last block on March 31st was 173,804.  So to get to 210,000 means there are 36,196 blocks remaining.  At 144 blocks/day (based on impossible situation of hash rate not rising or dropping) there are 251.36 days remaning until the block reward adjustment occurs.

That puts the date sometime on December 7th, 2012.
At this point, those betting on it being December 9th or earlier are on the winning side.  The wagers are 4X more for that than for the "later than December 9th" side:
 - http://betsofbitco.in/item?id=312

From the November BTC/USD low of $2.20 the current exchange rate at $4.85 is up 108%.  From the November difficulty low of 1,090,715 the current difficulty at 1,626,553 is up 49%.  So I suppose the difficulty still has room to rise or the price has room to drop because early estimates already just a few days into this next adjustment period show even further capacity has come online.
 - http://bitcoin.sipa.be/speed-lin-10k.png

It's still early enough that we could still see a November date, but I think the chances of a January 2013 date have now been completely eliminated barring a catastrophe.

thank you for this awesome update, Mr. Gornick.

I hope the date will be "pulled" even further to an earlier date by rising adoption / exchange rate / mining activity throughout the year ;)

Expect it:
 - https://bitcoin.org.uk/forums/topic/486-announcement-a-public-company-is-being-formed-to-enter-asic-bitcoin-mining-marketplace/

December 21st. Just for shits and giggles.

Here are a couple of stupid plots of block chain length against time.

This one clearly shows we're on target for a late November reward halving:
http://i44.tinypic.com/27ywfew.png

And this one shows it's definitely late December:
http://i40.tinypic.com/28gxz6r.png

Hope that helps!

I doubt Vladimir will be able to have operational mining capacity early enough for this to be relevant here.

looool
Just couldn't help myself.... :)

It could end up being a photo finish!  This last adjustment period id is looking like we'll end up with a 3% drop in difficulty.  Some explanation for that drop might have to do with the mining on blocks that became orphaned, thanks to miners that hadn't upgraded to code that supported changes to the Bitcoin protocol.

That puts the date late December 8th, 2012.  The bet says December 9th or later so there is still more than 24 hours cushion for the "December 9th or earlier" side of the bet (the "agree").  But a lot can happen yet.  With 22% margin, either the price needs to go up or there will be more GPU miners droppng out.
 - http://bit.ly/HEzoMm  (mining profitability currently 22%)

If, due to exceptional circumstances, we end up with a diff drop of 3% that doesn't reflect a drop hashrate, then that difficutly was measured "wrongly" and we're hashing blocks faster than 1 block per 10 minutes in the coming period, which will effectively move the date closer, no?

Yup, but for some reason that hashing in the last couple days hasn't been rebounding to those previous levels.  So there probably are other contributing factors.  There has been some selling of hardware as some miners unload GPUs and buy FPGAs (here's one example, by the person who held at one time the record for "fastest rig" https://bitcointalk.org/index.php?topic=75616.0 ).
 - http://bitcoin.sipa.be/speed-lin-2k.png

So if those GPUs get sold to others who will be mining, that hashing will not just return but will be in addition to the new FPGA hashing purchased using the proceeds from the GPU sales.

But with a sub-$5 BTC/USD and this difficulty level, those with GPUs and are paying $0.15 or more per kWh are just barely breaking even.  Whether or not the new hashing from FPGAs more than compensates the lost hashing from those dropping out is the reason that bet could still go either way.

It's turning into quite a contest!

Now, going forward if mining keeps the target 144 blocks per day from here (yes, a big stretch but on average ... 144) the date for block 210,000 has moved later and now sits about noon on December 9th, 2012.  It was targeted at December 7th, at one point.

 - http://betsofbitco.in/item?id=312
 - http://bitcoin.sipa.be/speed-lin-10k.png

BTC - 10 minute blocks, retarget every 2016 blocks, 2 weeks               
1/3/12   160370   8018500   33%   50   7200
12/13/2012   210050   10500000   13%   25   3600
12/13/2016   420434   15750000   4%   12.5   1800
12/13/2020   630818   15960012.5   2%   6.25   900

I did the calculation 1/3.  Annual inflation rate will drop to 13%.

Right now it is at 29.5% annual (dropped below 30% threshold earlier this month).  Hadn't looked at it recently.

Once the BFL Mini-Rigs start hitting the street at 25GH each, you can bet your bits the difficulty will rocket.

Imagine, the Network total is ~11 THs, each miniRig runs 0.025, so for every 40 rigs turned on an extra TeraHash is added to the network.

This is going to be very interesting, and very bad for anyone still mining on video cards (me).

EDIT: as pointed out, 25GH is 0.025TH, not 0.25TH

Apparently 3 pm is too early for me to do maths

I believe your math is off here. If a "mini-rig" is 25 GH, then it takes 40 of them to get 1 TH.

25GH=0.025 TH or 40 miniRigs for 1 TH

...close enough  8)


*is there like an alarm in your head for when someone is wrong on the internet? I swear I've never gotten a useful reply that quickly

"Hey man."
"WHAT?"
"HEY MAN, YOU DEAF?"
"NO, BUT I'M GOING CRAZY: GOT THIS ALARM GOING OFF IN MY HEAD WHENEVER SOMEONE SAYS SOMETHING WRONG ON THE INTERNET"
"MAN, THAT'S GODDA BE LIKE... CONSTANTLY?!?"
"WHAT?!?"

That was a useful reply no?

Yes, and it's never happened that fast on the intertubes

Some people do use rss readers to keep track of their favorite threads on forums. You might understand when you use something like Liferea or RSSowl. When providing tech support to those in trouble, a feed reader is a must.

@D&T reply LOL

Oh, I misunderstood, thought you meant only bad replies come fast including this one. I get it now.

Good point:

I swear I've never gotten a useful reply that quickly  ::)

I swear I've never gotten a useful reply that quickly  :)

Interesting, I read it the second way (as intended by the author). I didn't even consider the first possibility.

I wonder what exactly determines which way one reads it.

I'm also astonished that I didn't even realize there was ambiguity at all until quite a few posts later. I wonder how often this happens to me? Did you guys spot this from the beginning?

Yeah, I didn't see the other reading at all until pointed out. I think if you know the person at all you probably pick the right reading automatically.

I imagine people read the bible the same way, completely oblivious to the authors true intention.

Thus is the folly of the written word.

Update:


Well, that latest adjustment certainly moved the needle a bit.

At block 179,424 now, there are 212.15 days left presuming 10 minutes per block going forward until the adjustment.  That lands it at the beginning of the day, December 8th.

 - http://betsofbitco.in/item?id=312
 - http://bitcoin.sipa.be/speed-lin-10k.png

As it stands, I see no reason why the difficulty is going to fall anytime soon with all the new FPGAs already ordered or coming online that will remain profitable even if the price drops to half of what it is now. I think it's pretty safe to say that if you think the price per coin is going to stay the same or rise then we'll see the date before December 9th, 2012 for sure.

On the other hand, if you think the price is going to drop sharply then difficulty could go down again as tons of GPU miners go offline. I don't personally see that happening anytime soon. We had a good 6 months of early-adopter GPU mining before the difficulty/price really started to explode around the 9 month mark and anyone could GPU mine easily. Even CPU mining became profitable again for a short while.

I think with the FPGAs we're going to see GPU mining start to die off and the difficulty rise well before the 25 BTC reward drop. The only thing I'm not certain of is if the price increases will be as sharp as they were last summer.

I think the only reason why the difficulty has dropped over the last month or so was the elimination of that botnet. It would seem that we've actually been increasing in difficulty steadily since January otherwise.

Let's say the difficulty in December is up over 15% from here.

But to get there from here saw a 10% rise in the next adjustment, then a 8% drop in the one after, over and over for the next 14 adjustments remaining before block 210,000.

Even with the difficuly increasing, the date for 210,000 would be pushed later, past December 9th even I believe.  That is because the faster hashing burns through the calendar days on the way up and does not more than offset the death march that occurs on the calendar when trying to get to the next adjustment when hashing is below the difficulty level.

So it isn't just a question of will the difficulty be higher, but will it be volatile from one adjustment period to the next (on net, pushing the date further back), or will it be an even steady increase along the way ( pulling the date to be earlier ).

I have a script that projects what the date of the first 25 BTC block will be based on the current block rate. It's been doing it for the last month or so every day. It's currently somewhere between December 7th and 8th (times are GTM+1): http://pastebin.com/bTaEHADP

Script is here in case anyone's interested: http://pastebin.com/SnybcMKF

Heh, the last difficulty adjustment was down 8% and halfway through the next it is down about 4%.  So even though difficulty is higher than a month ago, the estimated arrival of block 210,000 (using the target of 144 blocks / day) has been pushed back, to middle of the day, December 9th, 2012.  

 - https://docs.google.com/spreadsheet/ccc?key=0AmcTCtjBoRWUdHVRMHpqWUJValI1RlZiaEtCT1RrQmc

 - http://bitcoin.sipa.be/speed-lin-10k.png

Bettors are still on the side of a Dec 9th or earlier arrival:
 - http://betsofbitco.in/item?id=312

But looks like difficulty finally caught up to the BTC/USD and is stuck around these levels until either more efficient technology (including acquisition cost) arrives or the BTC/USD begins to move.

 - http://bitcoin.sipa.be/speed-lin.png

I would consider it being before 9th of december according to my calculations.

You know what happens in the future?

^ Don't you?

No, I just know some basic maths.

I prefer the psychic approach.

Heh, your statement is fine but doesn't say that it is based on the assumption that hashing between now and then occurs at the "one block every 10 minutes" rate, which is an unknown.

Well, I made a date approach like a month ago and took in mind hashing power,difficulty increase, quantity of blocks solved, typical deviaton ( I think it's called so in english) of total miners per week, Moore's law and some other factors.

What I obtained was a date closer than 9th of November

Chart showing how many days per block.

https://i.imgur.com/xN07x.png

Charted from this data:
 - https://docs.google.com/spreadsheet/ccc?key=0AmcTCtjBoRWUdHVRMHpqWUJValI1RlZiaEtCT1RrQmc

Running from the current block and estimating the target of one block every 10 minutes, means there are a little over 183 days to go.  That puts the date for block 210,000 to early morning on December 9th.

The wager on Bets of Bitcoin agrees (nearly 3:1) that it will not be after December 9th:
 - http://betsofbitco.in/item?id=312

Latest update:

Running from the current block and estimating the target of one block every 10 minutes, means there are a little over 163 days to go.  That puts the date for block 210,000 to late in the day on December 7th.

The wager on Bets of Bitcoin agrees (nearly 3:1) that it will not be after December 9th:
 - http://betsofbitco.in/item?id=312

So who is hosting The very first Bitcoin Block party?  ;D

IF all these mega tera ultra super mining coffee warming kitchen appliances come out prior to the block split wont these things make the split happen a LOT sooner?

Not necessarily.  It difficulty were to shoot up one time, and then drop by that same amount the next, then it would actually cause the date to be pushed back.  Here's an explanation:

ahh.. interesting

Approximate 5 months left until the block reward halfs, get ready people!

Get ready for what?

$10 price. Or shall we call it $12 actually ?

so mystery2048 is actually saying "BUY BUY BUY"?

imo it's already factored in by the markets. Is there a bet about a price jump when reward drops around?

Latest update:

Running from the current block and estimating the target of one block every 10 minutes, means there are a little over 150 days to go.  That puts the date for block 210,000 to early in the day on December 7th.

The wager on Bets of Bitcoin agrees (more than 3:1) that it will not be after December 9th:
 - http://betsofbitco.in/item?id=312

If ASIC mining comes online before then, that date could easily move up clear into November.

Latest update:

https://i.imgur.com/uFXM5.png

Charted from this data:
 - https://docs.google.com/spreadsheet/ccc?key=0AmcTCtjBoRWUdHVRMHpqWUJValI1RlZiaEtCT1RrQmc

The last update took about 13 days and two hours, versus the 14 days it would have taken if blocks were being solved at the rate of exactly one per ten minutes.

Running from the current block and estimating the target of one block every 10 minutes, means there are a little over 141 days to go.  That puts the date for block 210,000 to late in the day on December 6th.

The wager on Bets of Bitcoin agrees that it will not be after December 9th but it is at less than a 3:1 ratio:
 - http://betsofbitco.in/item?id=312

Mining profitability is really high right now:
 - http://www.blockchain.info/charts/miners-operating-profit-margin

So I suspect we'll continue to see an increasing difficulty, and if done so gradually as has occurred for these last few, ... the date for block 210,000 arrives even sooner.

110 days left at 10 minutes per block.  That moves the date to the early hours of December 4th, 2012.

December 3rd now.    If it continues increasing, even to a lesser degree than we've been seeing recently, Block 210,000 will end up occurring in November.

 - http://bitcoinclock.com

Let's hear it for November! woohoo!

Anybody throwing parties?

I would schedule one but we don't know when the next-era block will be found. Planning a party is hard when you don't know when the event will occur. I bet in 2016, we'll know with much more certainty when it will occur as the date approaches.

Incidentally, the difficulty will adjust at block 209,664, about two days before the block reward adjustment occurs at 210,000, so even if a bunch of GPU miners drop out immediately, the difficulty will stay higher for the remaining 1,680 blocks -- possibly extending that difficulty adjustment period out several additional days (adding a little insult to the 25 BTC per block injury.)

Seals is gunna have a huge party, I don't care when it happens :-)

We should know day and rough time of day about a week out I'd think.

Agree, will be steadier next time, but probably always a bit turbulent timing afterwards.

Gunna be some looooow supply around the holidays.

Is it a coincidence that the halving date is close to the end of the world date? I don't think so :D

I'm tempted to bet on December 21st 2012 as the date the first block of 25 is generated.  Isn't there a site somewhere that we can make that sort of bet?

The Myans were actually just counting down the to the first subsidy cut.  The meaning of their calender just got lost in history.

You'ld lose choosing that late of a date though.  The range of likelihood is now between late November and early December.

 - http://betsofbitco.in/item?id=312

lol, from that date on, you only have to make half the sacrifices to the gods ;)

The even needs a name.  "Block reward adjustment day" doesn't necessarily roll off the tongue.

Some might refer to it as their GPU retirement day ..  ;D

How about "Market Day" since we'll all be DDOSing mtgox to try and figure out what the market is doing that day.

If we get an ASIC release, and it's looking likely at least one of them may drop, we might be looking at something prior to Thanksgiving, even.

Whatever day it is we should all start a google video conference and get drunk.

Maya have predicted with great accuracy:

21 dec 2012 

;D

I like this guys idea :D

Shouldn't we be getting stuff from silkroad instead?

Let's all drop acid as we watch the price skyrocket.

fuck yeah. It will go down in the history books as the "night of the crypto-hippies".

December 2nd!

86 days left.

The "two week" adjustment cycles are arriving in 12.5 days, 12.7 days at this pace of growth:

https://i.imgur.com/a8y32.png

 - https://docs.google.com/spreadsheet/ccc?key=0AmcTCtjBoRWUdHVRMHpqWUJValI1RlZiaEtCT1RrQmc

I don't know where to post this, so here it is :

are there any concerns about something like Y2K syndrome ?

are miners supposed to change something in their code ?

will the number of btc per block be the only thing that will change ?

Everything is taken care of already by Satoshi. It's in the rules. A block with number > 210,000 giving a coinbase transaction of greater than 25 BTC will be invalid and rejected by honest miners. Afaik that's all that will change (it will not really change, the rule has been there all the time, just didn't take effect because block numbers have been < 210,000 so far.

There might theoretically be a bug, but I'm sure a lot of devs and others have checked.

Not many places for bugs to hide in that code.

And they've tested it in Testnet.

one risk is the majority of pools not adhering to the rules

"make block reward 100 BTC instead of 25 BTC" might something the "syndicate" could decide... bitcoin would drop to 0.0001 USD in no time, though. This is why I highly doubt a majority of pools ops would do such a stupid thing.

How about this theoretical code buried in someone else's closed-source codebase?


However, I think it is unlikely this was written into any implementation of consequence, with an even smaller chance of the bug surviving until the reward is halved.

More importantly, the rest of the network would reject those invalid blocks.

I think his point was that a "syndicate" of pool ops could form a majority of the network and go rogue, forcing everyone else to either accept the changed rules or risk breaking the network due to having much less hashing power to secure it.  Right? (not that I think this is likely to happen.)

Miners would notice that 25 accepted, valued bitcoins are worth far far more than 100 do whatever we want accepted nowhere bitcoins so profit motivated miners will secure the valuable chain for valuable pay.

Anyone at any time can start assigning themselves 100000 'bitcoins' or 'hokeycoins' or whatever they want to call them. All that matters is that people want is real bitcoins and they don't want that crap. Break the rules and everyone knows you don't have bitocins, they know it automatically, you just get ignored.

The nodes following the protocol won't even relay those blocks.  So the only ones that would know about them are in this mining cartel/syndicate.   That becomes a hard fork condition and the economic majority is unlikely to accept a fork which devalues their coins.

Miner majority has no power in that case.  

If MtGox accepts tx from 25 BTC blocks and merchants accept tx from 25 BTC blocks and FastCash4Bitcoins only pays out on tx from 25 BTC blocks, and most wallet providers only show users 25 BTC blocks and full nodes reject everything but 25 BTC blocks, then the 100 BTC blocks won't have any value.

Now what would suddenly be very profitable would be the miners who broke from the "alliance" and continued to mine 25 BTC blocks.   There is significant economic value for them and with most of the miners gone the value per MH suddenly quadrupled.  

December 1st!

If the majority of pool-ops implement the rule, they have >51% and it is irrelevant what the rest of the network thinks of it.

EDITed because of what DeathAndTaxes said above.


Wow, I really didn't think this through. Thanks for pointing this out, deathandtaxes.

same here. Satoshi is so good. +1

The switch to 25BTC/block is gonna bring a lot of change to the network, especially considering ASIC miners will start trickling in at the same time. I started a bet http://betsofbitco.in/item?id=673 (http://betsofbitco.in/item?id=673) for whether the difficulty will go up or down after the switch. It's a really difficult question because the ASIC miners will bring it up, while FPGA/GPU miners will be leaving en masse. what do you reckon? Take a bet.

I am not interesting in betting on this (Bitcoin is a big enough gamble for me right now) but I would like to continue exploring this discussion more. 

Let’s assume that BFL does begin shipments by the week of November 12 or sooner.  I toss this date out as a reasonable guess because of allot of real world factors that will force them to do something on or before this date.  Now they plan to offer a systematic approach to delivery that will take them out to the end of December to get all pre-orders out.  That is significant amount of equipment hitting the street in a short amount of time.  This act alone will cause difficulty to go up one would think.  Also keep in mind that many BFL equipment users now will need to ship their equipment back so we could see all kinds of volume changes for about a month or so. 

Now this post has listed December 2nd as the proposed day we go from 50 to 25 so that should or could cause difficulty to go down due to smaller operations dropping off. 

These two acts alone should not cancel each other out because the proposed BFL ASIC product is so significant that difficulty will jump even as large numbers of folks go to other currencies to use their equipment.

Other ASIC solutions will come online cause the difficulty to rise but not too much since the masses have purchased BFL and will not be cash positive to explore investing in other equipment.   Late comers will consider the alternatives for many reasons so their products will come online after the New Year starts.

Now the real odd question to all of this is the price per BTC.  If this jumps up higher who knows but if it drops due to fewer folks mining/using the coins this could cause a whole host of additional outcomes. 

All I can say is that starting in October to February it is going to be some wild times in this Bitcoin world. 
I would love more input to this because this is my opinion and I am trying to get as many factors ironed out as possible but one man’s point of view is what it is. 

Well, this last one was just over 13 days, but still enough to pull the date for block 210,000 to a November date ... November 30th!

Fortunately for GPU miners, the exchange rate has been rising too, so profitability is still pretty good:

https://i.imgur.com/k5DY2.png
https://i.imgur.com/w3Nc2.png

 - https://docs.google.com/spreadsheet/ccc?key=0AmcTCtjBoRWUdHVRMHpqWUJValI1RlZiaEtCT1RrQmc

 - http://blockchain.info/charts/miners-operating-profit-margin

I'm seeing the event referred to as "Halving Day".

What sucks is that the specific day isn't known ... and likely won't even be known with any degree of certainty of +/- 24 hours accuracy until maybe within a week of it happening.

I think that the ASIC thing is kind of unfortunately timed. I would have liked to have seen what would happen if there was no transition in technology at the time. What if the halving occurred and mining was only at a 10% profit margin, suddenly putting everyone in the red by 40%? How would the market react? How would the miners react? But the conditions here are actually a little uninteresting. The price/bitcoin is so high that even a halving will keep GPUs slightly profitable, while ASICs start to roll out and will get acquired to fit into the limits of the 25 btc reward. This "First Halvings Day" will be relatively without any drama. I don't think it will give an accurate picture of what will happen when we go from 25->12.5.

You seem to be disappointed by this.

11/30/2012

Yup, that target date ... still Nov 30th (Friday), but early in the day (UTC), so even a small increase will cause it to land early, like on the 29th (Thursday)

 - http://bitcoinclock.com/

So if there are any halving day events ... for party planning it is looking like it perhaps might occur Wednesday in the U.S., Thursday in Europe / Asia.

There still are some wildcards though ... GPU miners could start liquidating in larger numbers soon, trying to get a jump on others who will mine until the is no question that GPU mining's days are oover.  This loss of hashing capacity could push the date later, maybe to December again.   Or a first run for some ASICs could pull us ahead by several days, like to the 25th or earlier.

It's as if the market knew the halving was coming?  :o

A few are.  There isn't a rush to the exits though, from what I can tell.


Thirty days left, target currently shows early in the day on the 29th.  For it to drop to December there would have to be a pretty big drop. 


It looks like halving will occur before any BFLs arrive in anyone's hands.   Maybe the early shipment to the testers, but even if they ship that last week of November, that's nothing that would cut short the adjustment period much more than a day or two.

So, in western hemisphere timezones, this could come as quickly as Tuesday the 27th or in Asian timezones it could still end up occurring late Thursday the 29th (barring any unexpected swings in the hash rate).

This is a week after Thanksgiving, so that won't interfere.

Who'll be the first to book a table for the first ever halving celebration?

No, it's not like that at all. The market didn't see the halving coming and thus create ASICs to ensure it was frictionless. Second Halvings Day will be a lot more interesting because we will see if people are forced to drop out, or if the reduction in inflation will keep all miners profitable. In this case, we won't see much because some miners who can afford it are switching to a technology that is 40x better.

Which may also happen on Second Halvings Day and Third Halvings Day, etc. My feeling is that subsequent Halvings Days will become a lot more boring. This first one will be the most turbulent.

Okay

The market definitely knew the halving was coming, that much is known ... what it did about it is less known.

I'd say it is safe to say that design/build/test pipeline for ASIC's, which has been well over a year in the making, had an eye on the halving date as a loose milestone target date ... how could they not have? The "market" is a reflection of the decisions and thoughts of many individuals ...

As difficulty goes up (more than 6 blocks found per hour), the estimated time for halving approaches more rapidly. Using bitcoinclock.com , it's fairly easy to see that the halving will occur between 1800 hours 11/27/2012 and 0600 11/28/2012 with current 'block finding trends'. ASICs entering the market would have a serious effect on this, however.

at this point its up to the ASIC developers. they could be the sole decider of this bet.

they at most will only be testing their hardware before the halve now and they could throw in a lot of machines to test if they have them ready before the ~ nov 26 calculation and then take the hardware off after difficulty increases and thus less blocks be made everywhere but first scare off people to sell their hardware and no longer mine

2052, OMG it is actually going to happen.

shudder

where's the best btc block halve countdown clocks?

Only bitcoinclock.com comes to mind.

i know the countdown's styling is still ugly, but i'm happy to share my code:



the code is ugly too, but it works :D

Isnt it rather simple? If a block is found every 10 mins and we only have currently around 1900 blocks left until reward drop. That would mean 316 hours left before the drop happens which is about 13 days.

i wanna know the minute it's set to halve

Well that's probably more determined more by luck now than anything.  It is looking like either sometime on the 29th (GMT) or possibly late in the day (again, GMT) on the 28th.   

So it is getting pretty safe to say that if you were to attend an all-day "halving day" party on Wednesday, Nov 28th, 2012 in the U.S., you would be present to raise your glass for a toast at the point that block 210,000 is solved.

http://serason.com/projects/emccharts/countdown.php

REWARD HALVE COUNTDOWN

Yeah, duh, that's pretty much what it says on bitcoinclock.com.

haha, you will know only after the fact. It's kinda like with radioactive decay: you never know exactly when shit happens and you can only make probabilistic assertions over periods of time.

Hopefully probabilistic uncertainty is the only common property of reward dropping and radioactive decay.  ;D

ftfy

This clock does not tell in which timezone it is. Two guesses; either local or UTC? Anyway, it should be noted on the site. No feedback address there?

I noticed that a couple of weeks ago. Fortunately now they added this "1 week, 4 days, 14 hours, 30 minutes", which is true wherever you are.

Very cool... how accurate is this?

It's an estimate as it can't know either future hashing capacity or variance.

In 2011 there were adjustment periods with so much new capacity coming online that it took just 8 or 9 days to reach the next difficulty adjustment period.  (The fastest was in 2010, in under 4 days).    Later in October 2011, as a few miners were powering down it took 17 days to reach the next adjustment period.

But since early June there have been a dozen increases in a row though by relatively small amounts (near 10% or less), and so far the current one is about even with no increase or decrease apparent right now.

So with just about 10 days left, the resulting likely time range is narrowing.

If you are in the U.S., it is looking quite likely that the halving will occur on Wednesday Nov. 28th.    Though it is entirely possible that more capacity could come online and it occur on the 27th, or it could slow and it would be later on the 29th.    We could see an even earlier date if at the 11th hour here some ASIC capacity were to reach Bitcoin main net, but there's nobody saying that is likely to occur.   And I doubt many miners are powering down their hardware yet, so I don't think we'll see a slowing.

In fact, from looking at that along with the time, you can calculate exactly that the time shown is UTC.

bitcoinclock.com

lol, nice bump.

yes, the reward drop is in UTC, but i guess i can write that on the site...

Reward-Drop ETA: 2012-11-28 22:58:41 UTC (4 days, 11 hours, 30 minutes)

Has anyone setup an officiial block party irc channel yet?

It seems to be using 600 seconds per block, which makes it not very accurate until a few hours in advance. With the average of the last 100 blocks being about 570 seconds, the estimated time is currently ~5 hours off.

Current estimation with 570 seconds: Wed Nov 28 17:22:04 UTC 2012

Except we have one last difficulty adjustment coming before block 210,000.

Interestingly, however, the estimate for the next difficulty is at about the same level as the current difficulty.   

So barring any changes in mining capacity (or extreme swing as the result of variance) it is looking like the halving will occur Wednesday afternoon/evening (U.S. timezones)  near the midnight hour for much of Europe and early morning Thursday in Asia.

ok... so aprox. 3 days left...

still don't know if we should celebrate this or not be happy at all :)

I think there is a minor flaw in the design of the bitcoin; in calculation differency, the change should be accounted, so instead of "changing diff to a value which would have gave 10 minute interval last 2 weeks" the rule should be "changing diff to a value which gives 10 minute interval, if the calculation power changes as last 2 weeks". Shortly, it should have been extrapolated. If so, the 25BTC day could have been calculated more accurately already 4 years ago.

But it's a minor flaw, current rule just adds some variancy and is just fine.

I think, thos who already have bitcoins, should celebrate. Those who does not have yet, should need not.
The price is already rising.. ;-)

I'm not convinced.  I think it's possible that your scheme could result in a less stable difficulty, with the difficulty adjustment continuously overshooting, overcorrecting.  Like watching a novice trying to steer a boat.

From a macro perspective that's precisely what happens anyway.

Just like anything in nature, or markets; there is never an equilibrium.  Any appearance of such is simply a frozen snapshot in time, that doesn't reflect reality seconds before or after the snapshot was taken.

Equilibrium is forever sought, never attained.

true, but nite's suggestion would amplify changes in difficulty. for example let's say the network hashrate doubles and blocks are solved every 5 minutes. we would have a huge difficulty adjustment sure, but under nite's system, it would assume the network hashrate was going to double *again*.

It would 'make things worse' on cases when first hashrate is first increasing and the suddenly starts decreasing or vice versa.
However it would make things go better when hash rate increases or decreases steadily or stays constant. And this case is 99% of the time..

Ie, if the hashrate has doubled, we have a *good reason* to assume it will most likely double again in the same time.

Technically addition would be very simple, just add "+ delta hashrate" to the formula.

200 blocks left... It can happen tomorow.. :)

given that "tomorrow" can mean a lot of things depending on timezone, this is very likely to be true.

We now have 170 blocks left. If we assume these last blocks are solved at a rate of 6 per hour, the network has spent about 36 days less than four years to solve 210,000 blocks. That's about 2.5% faster than 10 minutes per block, ie. 9:45 minutes per block.

Even if your algorithm is more accurate than the one in place now, is it even worth the added code complexity to get closer to 10 minutes than 9:45 is? Why would it matter at all that blocks take, on average, 15 seconds less to solve? I'd say it's completely unnecessary to adjust anything, and the 2.5% difference will make no measurable difference to how the network operates at all.

I agree. 10 minutes is arbitrarily chosen anyway. Accuracy is not a goal here.

That's quite much true, ie this is more question of opinion. The functionality of bitcoin practically would not change and current algorithm is very good. Just being as pragmatic as I am, I would have done it differently.

We can argue as to whether Nite69's way would have been better or not, but now that the network is already up and running it would be dangerous to make such a change.  Old clients would reject blocks which meet the new difficulty requirements but not the old ones resulting in a hard split of the blockchain.

Any marginal improvement the change might bring is certainly offset by the difficulty of getting all the old clients updated.

If I designed the difficulty algorithm I'd look at the time taken from block 0 to the current block and compare it to the number of blocks times 10 minutes and adjust difficulty that way. So instead of the difficulty adjusting to the rate, the difficulty adjusts to the expected number of blocks for all time.

Well, yes. That would be even better. Perfect.

Actually, in my suggestion, it would cause *some* problems, if the hash rate dropped to half.. ;-)

But it is also true, this is just speculating. Cannot change it any more.

Intriguing. Seems to me it would work. Of course it would've had to have been introduced from the beginning.

I see problems. after random long blocks you would have to set a minimum difficulty. what is the problem with the current design? just set your watch according to bitcoin blocks if you must, not the other way round

Only after a block lasting 2 weeks.

Edit: no, not even then. Halving the difficulty would be enought.
 

Just so people know, this block could be found within 2 seconds of the prior block or 2 hours. That's unlikely, but I did see a block once take over 60 minutes. Because of this, bitcoinclock can give an approximation, but you really need to stay tuned to blockchain.info.

Yes. It's just another way it could have been done so I was being academic.

yeah, i still remember this 90-minute one... https://bitcointalk.org/index.php?topic=118930.0

what do you mean by "stay tuned to blockchain.info"? for what, the blockcount? that part isn't an approximation :)

3 blocks left :)

woohoo! today is the big day! :) :) :)

So, it ended up being November 28th in most every populated timezone.

Specifically, 2012-11-28 15:24:38 UTC
 - http://blockchain.info/block-index/322335/000000000000048b95347e83192f69cf0366076336c639f9b7228e9ba171342e

I was really expecting there to be some larger exchange rate volatility over the last few days.  I was expecting GPU miners to already have been selling in quantity on eBay.  

But it has been pretty quiet.

I said it before and I'll say it again: reward halving has been factored into the price of btc/usd for months now.

Let us wait 'till december has passed with judging this. I doubt it's been priced in correctly.

What happens when ASICs become cheap and available, and the network hash rate goes up by a factor of 10, say?

Suppose the difficulty only just changed, so we were expecting it to take 2 weeks until the next difficulty change.  We're running 10 times normal speed, so the difficulty changes in just 1.4 days instead of in 2 weeks.

Under the current scheme, the difficulty is adjusted by the maximum factor of 4, bringing block generation time up to a more reasonable 4 minutes, and on the next adjustment it's adjusted by another 2.5x taking us back to 1 block per 10 minutes.

With your proposed scheme, after the 1.4 days there would be very little adjustment.  The average time-per-block over the 4 year history of bitcoin won't have been affected much by the fact that the last 2 weeks' worth of blocks was found in just 1.4 days, because 12.6 days is pretty insignificant compared to the 4 year history.  So the adjustment will be minor, and we'll continue seeing blocks every minute.  It will take quite a while until the 10 minutes per block status quo is achieved again.

I'm having problems thinking about this. At first glance I thought like dooglus (bolded part). Then I thought a little about it and had some sort of unclear heureka moment (if such a thing exists) and thought it would work really well. Now I'm back to dooglus way of looking at it.

This is really moot to discuss as everyone agrees, but how exactly would the new difficulty be calculated?

If you could figure out the expected block height (for all time), the actual block height and the block rate over the last 2016 blocks then...

1. Add 2016 to the expected block height and take away the actual block height to get the number of blocks desired.
2. Determine the expected number of blocks to be created at the current rate.
3. Adjust difficulty to make expected rate hit the desired number.
4. Limit difficulty change to prevent large changes.

So if we have a difficulty change at block 2016000, and 2001 weeks have passed then we expect to be at block 2017008. Let's say over the last 2016 blocks, they were created at 8 blocks an hour. We need to reach block 2017008 + 2016 in two weeks time which is block 2019024. This is 3024 blocks more than 2016000, so we want 3024 blocks. This means we want a block creation rate of 3024/(14*24) an hour which is 9 blocks an hour. To try to get this rate we can adjust the difficulty by 8/9 = 0.889.

I probably explained that terribly but hopefully I got across the general idea. I didn't think about it too much and it is indeed academic, it doesn't matter.

what is the "current rate", how do you calculate/measure it?

I think his scheme, now that I understand it, is to work out how long it is supposed to be until the next difficulty change, calculate the current hash rate from the time taken to find the last 2016 blocks, and set the difficulty such that if the hashrate stays the same over the next period as it was for the previous period then the next difficulty change happens when it 'should', based on 10-minute blocks from the start.

So in my hypothetical situation in which everyone starts mining 10 times faster due to ASIC or alien technology, and assuming that the previous difficulty adjustment happened when it should have (since we've been using Matthew's system for a while), the next adjustment will happen 14-1.4=12.6 days too soon, and so the next adjustment period needs to take 14+12.6=26.6 days.  We know that at the current rate it'll only take another 1.4 days, so we need to increase the difficulty by a factor of 26.6/1.4 = 19 to get back on target.

If the hash rate stays the same, and we do end up with the next adjustment happening on the 'right' day, the next adjustment will reduce the difficulty by a factor of 26.6/14 = 1.9x.

Overall we've increased by 19x and then reduced by 1.9, giving a resulting adjustment over 2 periods of 10x, which matches the increase in hashing power.  So we end up back on schedule, but at the expense of having a very slow 26.6 days during which blocks took an average of 19 minutes each to find.

Do I understand it right now?

One morea cademinc thought; the difficulty should be calculated after every block, only input counted from a longer period (2 weeks?).
Ie for every block, count a difficulty which will result in expected block height in next 2 weeks (if hash rate stays the same).

yep, based on a rolling 2-week / 2016 block period.

I agree with molecular; The production has just halved, if the demand stays the same and no extra reserves are being used, the price should double.

Of course, when the price rises, some reserves are taken in to markets which slows down the rise.

But this is just speculating. We'll see.

Yeah but guess what: you're not the only one who came to that conclusion. And lots of people bought-in anticipating the rise in price... which itself caused the price to rise. That's what I mean by being "already factored into the price." Look at the price 6 mo ago vs today. Hey, it doubled! Coincidence? Only partly.

I think people expected asics to be shipped at least in november. That not being the case changed some things... many GPU miners will try for a few days more... :)

Yes, I was thinking along those lines.


No reason why not to do this, it should keep the difficulty more stable this way because much could happen in 2 weeks.

hmm.. did miners already start to turn off their machines.. 51 minutes since last block, 2 prevs are at 20 minute interval, block 210261

I think I'll keep mine running for a while.. but HEY! if the rate halves it will also halve the reward :-(


Edit: normal variance, I guess. F.ex. Slush hashrate does not seem to drop at all: https://mining.bitcoin.cz/stats/