The Difficulty Upgrade

So the latest Bitcoin Difficult increase was the biggest ever by the looks of it (A useful chart is at http://bitcoin.sipa.be/index.html) and a fair few people have noticed its impact. This has pushed the difficulty over 1 million and has almost halved the generation rate.

Pool Review: Deepbit

Deepbit is the biggest pool out there with some charts showing that it has just under 50% of the marketshare. Some people brand this a bad thing as it is taking away the decentralised nature that Bitcoin is based on, however for those people who just want to see numbers that keep rising constantly then this is the best pool for you.

Pool Review: Slush's pool

Slush's pool is one of the main pools, and is second in Hash share behind the giant that is Deepbit. This pool is the pool that I started to mine with and is very easy to set up, however this has become more difficult after a recent DDOS attack (but I'll come onto that later). The interface is very clear with colour-coded reward indicators.

This pool uses a Scoring system, which works out a reward by using the shares to tell the server how many Hashes the worker is doing and then the server calculates a score from that. The reward per block is based on your score divided by the pools total score. This is slightly more complicated than the Share/TotalShare method but it uses the same principal.

Near the 13.06.2011 there was a DDOS on Slush's Pool which took down the site and stopped all mining for a short time. New security measures were put in place including an IP whitelist and a new address for workers to connect to the server.

Like most pools, the Unconfirmed balance is only transferred to the confirmed balance after it has reached 100 confirmations with the Network. This ensures that the block has been discovered and is not invalid so the system does not pay out on an invalid block which could potentially disrupt the Network (an Excess number of Bitcoins thought to be in circulation than the amount actually in circulation). The time it takes for a block to be fully confirmed and a reward to be released can range anywhere from 2 hours to 12 hours Depending on the number of clients online.

Nean's Bitcoin Mining Guide

Right, so I've had 3 people ask me how to mine with a GPU given that the guides everywhere else are quite hard to follow and there are millions of methods.

Terminology

Bitcoin (BTC) - Internet currency

Mining - The process of 'creating' bitcoins by doing caclculations on the CPU or GPU

Mining Pool - I'll come onto this later.

Hash/s - The speed of calculations (normally measured in kH/s or MH/s)

Preparation

First I recommend downloading GUIminer from: http://forum.bitcoin.org/index.php?topic=3878.0

and create an account here: http://mining.bitcoin.cz/

If you use an ATI Graphics card then you'll need OpenCL from the AMD website: http://developer.amd.com/sdks/AMDAPPSDK/downloads/Pages/default.aspx

The Open CUDA for nVidea should be already installed, if not it's included in the latest drivers.

Configuring GUIminer

Once you've got GUIminer installed and have OpenCL/CUDA then open it and use File>New OpenCL Miner (I know some have CUDA, but it's used as a figure of speech) then in the top dropdown select Other.

In the host box type: api.bitcoin.cz

The username is then your http://mining.bitcoin.cz/ account name.second part I reccomend not making the second part too hard to remember as you'll need it later.

The password is also supposed to be easy to remember, not a random number/letter string as this increases the chance of failure. This is not your password on http://mining.bitcoin.cz/ though.

You then need to select your Graphics card from the final menu.

For comparison, my GUIminer screen (this is before the pool moved to api.bitcoin.cz):

Configuring the website

By this point you're probably thinking: WTF is all this shiz on the website?

Well first you need to go to http://mining.bitcoin.cz/accounts/profile/ and click 'Register new worker'. You then get this page:

Now the login suffix is the second part from GUIminer and the password is the simple password from GUIminer.

Then click save and return to profile. It should look like this:

That is the hard part over. The next part you just enter the wallet address you want to send the mined money too in the 'Wallet' box on the profile/My Account page (Clever, I know...). Now you have a choice here. If you want to automatically send the money to JB without having to manually do it, then enter the JB address into the box (It's on the http://bit.ly/jbcoins page). However if you want to control what goes to JB manually, then you'll have to download the Bitcoin client and put your own receiving address in. If you haven't already, click 'Start Mining' on GUIminer and you should be generating monies!

Bear in mind that unless you create a shortcut to GUIminer in the startup section of the start menu GUI miner won't start automatically on reboot, and to make sure it starts mining once open, in the 'Summary' tab in the miner, tick the autostart box.

The more nerdy bit

Slush's pool uses a score system: your score is worked out by the speed you are doing calculations (the hash rate). The faster/more you do, the higher your score. Your share of the 50 BTC released in the block is determined by your score divided by everybody elses and then some other math. On the My account portion of the website there are 4 number boxes.

The Red box is how much the system thinks you'll earn

The yellow box is how much you've earned but the system is confirming that you've earned it with the network.

The green box is what you have definately earned

Then the box below that is pretty clear.

The send threshold is how many confirmed BTC it takes for it to send the money to the wallet address.

This method is better than just having the http://bit.ly/jbcoins window open as that generates only 1-5 kH/s whereas the GPU method, although hard to setup, gets at least 7MH/s on even my 3 year old midrange card (~1400 times more hashes). The pooled method also increases the speed of getting a reward than solo mining, as having 50 GPUs working on the math is quicker than 1 GPU, so the pool has a greater chance of winning the block of 50 BTC and then you have a greater chance of a reward.

Link for Linux users (thanks to Peerkoel): http://forum.bitcoin.org/?topic=2636

More about it (Including Shiny youtube video): http://www.weusecoins.com/

Please post any Questions & I'll try to answer them.

~Nean