Bitcoin Forum

I set up a new mining computer Thursday night that has a hash rate of 640000 khash/s.  I also have my main system mining at a rate of 320000 khash/s.  Based on the probabilities provided via http://www.alloscomp.com/bitcoin/calculator.php, on average, I should see a block every 1.21 days (assuming 900 Mhash/s), and I should have a 95% chance of seeing a block in 3.625 days.  Since I've yet to see a block on either of these systems I'm beginning to worry that something has been hacked or there is some other problem. 

At what point should I assume there is a problem and clean off the systems and re-start?  Based on the 50% time, I estimate a 99% chance for 6 days of mining, which would be Wednesday morning.  The odds of 6 days of mining at 900 Mhash/s without a block is 1/100.

Anyone have any ideas on what to look for regarding a hack?

Some people seem to just be incredibly unlucky in terms of mining. I personally have 2 5870s and a 5770 hashing almost 24/7 and I went a week or more without a block, and just today found two apparently. It's all luck, and some people are just unlucky :)

Don't worry, and if you get tired of no results try joining a mining pool  ;D

3 possible ways:
- join the mining pool and see if shares are accepted
- run your client on testnet
- modify the miner to print more debugging stuff. Increasing target (lowering difficulty) also can help spot the problems.

Don't worry man, I know the feeling and it is perfectly normal. The same way sometimes you may see many blocks generated within a short period of time, sometimes you won't see any of them for a while (even above 95% - I have experienced that myself a few times).

Still, maybe there is something wrong with your miners.

Can you link me to the testnet and debugging documentation or thread?

Thanks!

Testnet:
https://www.bitcoin.org/smf/index.php?topic=1509.0

You simply run your bitcoin with -testnet flag and connect with your miner as usual. Current difficulty on testnet is 186 so it still takes a while to mine on testnet.

For debugging, consult individual miners threads.

I can generate something like ~500 khash/s (depending on how much I'm using the computer), using either a miner, or the default client.

The website given earlier suggests it'll take me at least 1791 days to have a 50% chance of getting a block. Being part of a mining coop has generated some small amounts, but I don't think it's likely to be worth it at all.

Thoughts

Testnet has been reset in the github source tree, in other words, if you compile from source you'll have a testnet with ~1 diff. Should be much easier to test :)

Any update?  Did you get a block?

I think you may be misreading your hash/sec number. If gethashespersec returns 640000, you aren't getting "640000 khash/s". You are getting 640000 hps = 640 khps (640000/1000).

In order to reach 95% probability, you'll need to run for 8483 days.  :/

Try mining on a 486DX next to your high end mining rig. If your expensive rig is so unlucky maybe the 486 will do better.

this

Unless you have a very high-end video card, you won't be able to get that hash rate.