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Bitcoin / Bitcoin Discussion / Re: testnet - 51 blocks orphaned in one shot

on: August 22, 2011, 12:39:04 AM

Quote on the plus side I gained about 0.02 coins in transaction fees when I picked up all the floundering transactions I guess I spoke too soon. The testnet bandit struck again. He wiped out all the remaining non-mature blocks. At least someone is having some fun.

Bitcoin / Bitcoin Discussion / Re: testnet - 51 blocks orphaned in one shot

on: August 21, 2011, 10:54:47 PM

Quote from: elggawf on August 21, 2011, 10:30:54 PM Quote from: fcmatt on August 21, 2011, 10:17:08 PM Isn't this the huge worry people have when it comes to deepbit being so dominant at one point? Not particularly, because at the very least people are going to notice if deepbit suddenly goes AWOL to fork the chain. I would tend to agree. In my case it was relatively easy for one well endowed miner to overwhelm my puny efforts. It's interesting that he let it run for nearly two days before cashing in, so to speak. That got me wondering, does a block ever truly get locked in? The coins mature in 120 blocks, but could he have payed his game a little longer and orphaned my blocks after I'd spent the coins? If it gets locked in at 120 blocks, that puts an upper limit on how much time a rogue miner has to drop in his alternate chain. If they don't get locked in, someone with > 50% of the hashing power could wait until their chain is a bit longer and drop it in. That would wreak a bit havoc, I'd think. Certainly all the miners who saw their coins vanish after they were confirmed would be upset. So, do they get locked in at 120 blocks? As you say, people would certainly take note if 50% of the hashing power suddenly went off-line for any length of time. And the miners in that pool (assuming it's a pool) would likely move elsewhere if their pool went AWOL. However, some of the newer alternate coins might be more susceptible if one or more of the larger miners wanted to attack before the mining base grows very large.

Bitcoin / Bitcoin Discussion / testnet - 51 blocks orphaned in one shot

on: August 21, 2011, 08:32:00 PM

I've been mining on testnet for a few days to help out the software developers a bit. I'll call that my donation to the projects. For the first couple of days it was chugging along at a block every hour or two. In the morning hours on 21 August I hit block 32256, and the difficulty dropped. The block rate went up to about three per hour.

Later that afternoon I noticed that there was suddenly a gap of nearly 700 confirmations in the list presented by the bitcoin client. The total block count shot up by several hundred and about two days worth of my blocks vanished.

This appears to be a case of someone with more processing power working off-line and then dumping all of their blocks into the network at once. Since they had the longer chain, my blocks were obliterated. It does show what someone with a significant majority of the processing power could do. For reference I was running at 440 MH/s, and there was at least one other miner generating blocks during this time. I haven't yet tried to estimate the stealth miner's hash rate. I would be interesting to see just what percentage of the hashing power he had. A very quick estimate is that he mined nearly 700 blocks for my 50. That would put it on the order of 7 GH/s, give or take.

Here's a screen shot of the client when I noticed that the blocks had vanished and a list of the time the blocks were generated from the debug.log file http://dl.dropbox.com/u/33346807/testnet_debug.log. The three non-generation transactions shown in the client were all originally in separate blocks spanning more than a day. They were basically undone until my miner generated another block (32887) that combined them with all the other transactions that were affected. So, I lost 51 blocks, but on the plus side I gained about 0.02 coins in transaction fees when I picked up all the floundering transactions. Good thing this was just the testnet. Otherwise, I'd be pretty unhappy.

Code:

08/17/2011 12:52 generated 50.0005
08/17/2011 13:05 generated 50.00
08/17/2011 14:22 generated 50.0015
08/17/2011 14:53 generated 50.00
08/17/2011 17:28 generated 50.011
08/17/2011 19:47 generated 50.0005
08/17/2011 21:21 generated 50.00
08/17/2011 23:28 generated 50.00
08/18/2011 00:22 generated 50.00
08/18/11 02:05 generated 50.00
08/18/11 03:45 generated 50.00
08/18/11 05:27 generated 50.00
08/18/11 05:44 generated 50.00
08/18/11 07:37 generated 50.00
08/18/11 10:30 generated 50.00
08/18/11 10:47 generated 50.00
08/18/11 10:59 generated 50.00
08/19/11 01:39 generated 50.00
08/19/11 01:43 generated 50.00
08/19/11 01:54 generated 50.00
08/19/11 04:16 generated 50.00
08/19/11 05:12 generated 50.00
08/19/11 06:24 generated 50.001
08/19/11 08:40 generated 50.0025
08/19/11 09:06 generated 50.00
08/19/11 10:10 generated 50.0005
08/19/11 13:33 generated 50.003
08/19/11 16:42 generated 50.001

##########This is where the orphans begin
08/19/11 19:42 generated 50.00
08/19/11 20:22 generated 50.0025
08/19/11 21:08 generated 50.002
08/19/11 21:11 generated 50.00
08/19/11 23:10 generated 50.0055
08/19/11 23:49 generated 50.00
08/20/11 03:07 generated 50.0005
08/20/11 05:03 generated 50.0005
08/20/11 05:08 generated 50.00
08/20/11 07:14 generated 50.0005
08/20/11 09:27 generated 50.001
08/20/11 10:25 generated 50.00
08/20/11 15:05 generated 50.0005
08/20/11 15:11 generated 50.00
08/20/11 15:51 generated 50.0005
08/20/11 15:55 generated 50.00
08/20/11 16:19 generated 50.0005
08/20/11 18:17 generated 50.003
08/20/11 18:20 generated 50.00
08/20/11 19:21 generated 50.00
08/20/11 20:46 generated 50.0005
08/20/11 21:00 generated 50.00
08/20/11 23:04 generated 50.00
08/21/11 01:59 generated 50.001
08/21/11 04:26 generated 50.00
08/21/11 05:20 generated 50.0005
08/21/11 05:59 generated 50.00
08/21/11 06:03 generated 50.00
08/21/11 06:05 generated 50.00
08/21/11 06:11 generated 50.00
08/21/11 06:30 generated 50.00
08/21/11 06:52 generated 50.00
08/21/11 07:00 generated 50.00
08/21/11 07:06 generated 50.00
08/21/11 07:24 generated 50.00
08/21/11 07:56 generated 50.00
08/21/11 08:46 generated 50.00
08/21/11 08:56 generated 50.00
08/21/11 09:18 generated 50.00
08/21/11 09:50 generated 50.0105
08/21/11 10:14 generated 50.0005
08/21/11 11:40 generated 50.02
08/21/11 12:20 generated 50.00
08/21/11 12:36 generated 50.00
08/21/11 14:02 generated 50.00
08/21/11 14:03 generated 50.00
08/21/11 14:23 generated 50.00
08/21/11 14:46 generated 50.00
08/21/11 14:48 generated 50.00
08/21/11 15:08 generated 50.00
08/21/11 15:18 generated 50.00
##########This is where the orphans end

08/21/11 16:05 generated 50.0205
08/21/11 16:18 generated 50.04
08/21/11 16:30 generated 50.00
08/21/11 16:40 generated 50.0005
08/21/11 16:43 generated 50.00
08/21/11 17:00 generated 50.00
08/21/11 17:00 generated 50.00
08/21/11 17:36 generated 50.00

Bitcoin / Development & Technical Discussion / Re: No blocks on testnet for 24 hours

on: August 20, 2011, 07:59:23 PM

I've been mining on testnet for the last few days, trying to help things along. 45 blocks so far. Wohoo, I'm rich...,or not.

Other / Beginners & Help / Re: What's your Mhash/s? (Pissing contest here)

on: August 18, 2011, 10:46:02 AM

15 blocks in a day! Too bad they're all on testnet.

Other / Beginners & Help / Re: Introduce yourself :)

on: August 18, 2011, 10:41:30 AM

Just trying to break out of this jail.

Other / Beginners & Help / Re: What's your Mhash/s? (Pissing contest here)

on: August 18, 2011, 02:09:42 AM

Running 2 5770s for a total of 440 MH/s. Currently mining on the testnet to help the bccapi development out a bit.

Other / Beginners & Help / Re: Introduce yourself :)

on: August 07, 2011, 02:54:09 AM

Just another post to eventually get myself out of quarantine. I guess I could do them all at once, but I'm lazy.

Other / Beginners & Help / Re: Introduce yourself :)

on: July 05, 2011, 01:40:14 AM

Hi, lurker here (it's what I'm good at) I've been lurking for a couple of weeks. Guess I'd better de-cloak if I ever want to play with the big boys and girls. I just got a rig set up with two 5770s, each running at about 190 MH/s with the stock clock configuration. I'm running on Ubuntu 11.04 (64 bit) using the phoenix miner and Reikoku's excellent Autominer scripts (http://forum.bitcoin.org/index.php?topic=19861.msg247956;topicseen#msg247956) scripts. And now the coins are trickling in. I'm now looking into tweaking the clocks.

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