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Topic: Proof-of-work difficulty increasing (Read 36575 times)

sr. member
Activity: 406
Merit: 250
March 25, 2015, 01:56:10 PM
#75
I thought about that but there wasn't a practical way to do smaller increments.  The frequency of block generation is balanced between confirming transactions as fast as possible and the latency of the network.

The algorithm aims for an average of 6 blocks per hour.  If it was 5 bc and 60 per hour, there would be 10 times as many blocks and the initial block download would take 10 times as long.  It wouldn't work anyway because that would be only 1 minute average between blocks, too close to the broadcast latency when the network gets larger.

Wouldn't this only be true if the total transactions contained in the 1 minute blocks had the same size as the total transactions contained in the 10 minute blocks? And as long as the global transactions per second (tps) doesn't change, there shouldn't be a huge difference between 1 minute blocks and 10 minute blocks in terms of blockchain size, no?

As for whether or not a 1 minute block time would work, I think that really depends. You would certainly see more orphan blocks and more confirmations would be required to achieve the same level of security but I don't think it's completely infeasible. Over 95% of nodes have a network latency of <40 seconds and by 1 minute, I'd expect this number to be over 97%.

Just out of curiosity but what do you think is an appropriate trade off between latency and block generation time? And how do you think number of nodes affects average network latency? Correct me if I'm wrong but shouldn't best and average case latency to be reduced (or at least scale with O(log n)) with a larger network size since all nodes in the network would attempt to increase their share of connections instead of forcing transactions to require more hops? (assuming this is how you implemented it. I could be wrong on this.)
sr. member
Activity: 406
Merit: 250
AltoCenter.com
November 04, 2014, 11:50:09 PM
#74
It was designed to become tougher and tougher as more and more people got involved, wasn't it? At least that's what basic indicates.
newbie
Activity: 14
Merit: 0
November 04, 2014, 11:35:13 PM
#73
We are poised to reach ~44.6 billion and can potentially reach 100 billion difficulty by the end of the year. Over the past year the network has seen huge increases in security.
legendary
Activity: 2128
Merit: 1092
February 09, 2014, 11:55:23 AM
#72
This topic brings back memories...

I generated 5 blocks today on my Pentium processor. Two of them were within 3 minutes of each other.

Heh. Smiley

Damn, hey theymos: Wanna send me a few? ahhahah  Cheesy Cheesy why hadnt I heard of btc back then Sad
hero member
Activity: 868
Merit: 1000
February 07, 2014, 09:34:34 AM
#71
Ugh, from 23 to 244 in 3 weeks. No wonder my 2600 khash/s system is over 10 days on the current block!

The good old days.  Cheesy
full member
Activity: 238
Merit: 100
Stand on the shoulders of giants
February 06, 2014, 06:11:17 PM
#70
Thats should go to the history text book Grin
administrator
Activity: 4228
Merit: 8647
March 21, 2013, 09:54:32 PM
#69
This topic brings back memories...

I generated 5 blocks today on my Pentium processor. Two of them were within 3 minutes of each other.

Heh. Smiley
legendary
Activity: 1227
Merit: 1000
March 21, 2013, 09:35:35 PM
#68
Next increase in difficulty in est. 14 days...

 Wink
member
Activity: 102
Merit: 10
July 27, 2010, 03:33:55 PM
#67
I wonder if that's due to bigger swarm, or heavier iron, or both...?
legendary
Activity: 3724
Merit: 1084
July 27, 2010, 02:41:23 PM
#66
Ugh, from 23 to 244 in 3 weeks. No wonder my 2600 khash/s system is over 10 days on the current block!
hero member
Activity: 574
Merit: 504
July 27, 2010, 07:02:15 AM
#65
I designed a page to show history of difficulty values and published the code at https://bitcointalksearch.org/topic/difficulty-587
sr. member
Activity: 308
Merit: 252
July 26, 2010, 11:09:19 PM
#64
It's a good thing all those phantom super-clusters went off line a few weeks ago or who knows how high the difficulty would have jumped to?  Grin
founder
Activity: 364
Merit: 3077
July 26, 2010, 11:04:58 PM
#63
New difficulty factor 244.213223092
+35%

I updated the first post.

date, difficulty factor, % change
2009          1.00
30/12/2009    1.18   +18%
11/01/2010    1.31   +11%
25/01/2010    1.34    +2%
04/02/2010    1.82   +36%
14/02/2010    2.53   +39%
24/02/2010    3.78   +49%
08/03/2010    4.53   +20%
21/03/2010    4.57    +9%
01/04/2010    6.09   +33%
12/04/2010    7.82   +28%
21/04/2010   11.46   +47%
04/05/2010   12.85   +12%
19/05/2010   11.85    -8%
29/05/2010   16.62   +40%
11/06/2010   17.38    +5%
24/06/2010   19.41   +12%
06/07/2010   23.50   +21%
13/07/2010   45.38   +93%
16/07/2010  181.54  +300%
27/07/2010  244.21   +35%
sr. member
Activity: 294
Merit: 251
Firstbits: 1duzy
July 17, 2010, 09:45:19 AM
#62
I value Bitcoin as an anonymous digital currency.  Although I'm not expecting to get rich, I'd like the ability to continuously generate enough Bitcoin to purchase desired services.

Is there any expectation that economic value per khash/sec (or client) per day will be at least somewhat stable?  Difficulty just increased 300%, and USD/Bitcoin just increased about 500% (although that may turn out to be a spike).  I do get that there's no necessary relationship.  However, perhaps there's an economic basis for one (however approximate it might be).

Try the Bitcoin Economics Forum
You should be able to find many discussions about this topic there.

This thread is about the proof of work difficulty number.
member
Activity: 182
Merit: 10
July 17, 2010, 09:41:26 AM
#61
I value Bitcoin as an anonymous digital currency.  Although I'm not expecting to get rich, I'd like the ability to continuously generate enough Bitcoin to purchase desired services.

Is there any expectation that economic value per khash/sec (or client) per day will be at least somewhat stable?  Difficulty just increased 300%, and USD/Bitcoin just increased about 500% (although that may turn out to be a spike).  I do get that there's no necessary relationship.  However, perhaps there's an economic basis for one (however approximate it might be).
sr. member
Activity: 416
Merit: 258
July 16, 2010, 11:35:32 PM
#60
In the Economy subforum, I have just written a post titled "Get rid of 'difficulty' and maintain a constant rate" which outlines a scheme which a new version of the BitCoin software could use to keep the rate of block generation absolutely constant at the cost of a slight increase in network traffic.

I would be very grateful for your comments.

ByteCoin
full member
Activity: 224
Merit: 104
July 16, 2010, 09:31:32 PM
#59
Now, correct me if I'm wrong, but now that block generation is taking a lot longer, doesn't that mean that the lucky person who got the block is going to take a lot longer to be verified by the network that he/she was the winner before they could ever spend it?

No, this isn't correct.  Finding the hash requires a whole bunch of effort, but the process of verification that the "winner" has found a matching block is by comparison a trivial exercise and doesn't take all that long.  Once they have found the block, they can spend those coins right away.

What this does mean is that the coin allocation system has now become a lottery, where new winners are receiving a block of coins worth a whole lot more (due to exchange rates and scarcity) than earlier blocks which were in comparison relatively trivial in value.  My question is, how valuable will this "lottery" become in the long run (in terms of Euros or Dollars per block generated)?

Essentially what is happening is that the computer is picking a random sequence of numbers (like a lottery) and if that computer happens to pick the correct sequence of bits, you "win".  The change in difficulty is something akin to playing a lottery that has you only picking six numbers vs. one with fourteen or a hundred numbers to win.  The odds are actually worse for a bitcoin block than even the worst of any normal lottery that has ever been conceived at the moment.
sr. member
Activity: 308
Merit: 252
July 16, 2010, 03:05:10 PM
#58
Ah ok, cool. I continue to be astounded by how much thought was put into this system to keep it balanced, nice job!
founder
Activity: 364
Merit: 3077
July 16, 2010, 02:43:51 PM
#57
Right, the difficulty adjustment is trying to keep it so the network as a whole generates an average of 6 blocks per hour.  The time for your block to mature will always be around 20 hours.

The recent adjustment put us back to close to 6 blocks per hour again.

There's a site where you can see the time between blocks, and since block 68545, it's been more like 10 minutes per block:
http://nullvoid.org/bitcoin/statistix.php
member
Activity: 70
Merit: 11
July 16, 2010, 02:09:04 PM
#56
Yes, about 20 hours.  (120 conf / 6 blocks per hour = 20 hours)  That's the normal length of time before you can spend it.  You'll know long before that that you won one.
So if the difficulty was increased so high that it took a day to find a winning block, that means the lucky winner would have to wait 120 day before they could spend it or about 4 months if everyone else was averaging about the same speed? Seems like at the high end of the difficulty, there is an issue with coin generation vs. being able to put it into circulation by spending. Wouldn't the long delay cause a lot of generated coin to be lost because anything could happen to the PC that won in a long amount of time if the winner had to really wait that long? They might un-install the program or the computer get eaten by a virus or power surge well before then.

I think that the overall network is generating the same amount of blocks regardless of the difficulty; the difficulty is intended so that the network generates a block in a relatively constant amount of time. Therefore, this confirmation time should always be around the same.

Satoshi or anyone else can correct me if I'm wrong Smiley
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