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Bitcoin is a decentralised crypto-currency; computers around the world constantly mine for bitcoins by solving complex mathematical problems. Once a certain number of problems have been solved, a block of bitcoins is released.
The value of bitcoins has shot up since 2009 (though it has come back down from a peak of around $1,000 per coin to about $500 per coin). This spike in value, as well as the resulting media attention, has resulted in a lot of interest in mining bit coins.
In this tutorial I’ll show you how to get started mining bitcoins with a Mac.
If you want to find out more about Bitcoin, or set up a Raspberry Pi as an additional miner, refer to the following tutorials:
Mining in Brief
Bitcoins are mined by computers solving incredibly complex mathematical equations, or hashes. When enough hashes have been solved, and the number required is always getting larger, a block of 25 Bitcoins–approximately 15,000 dollars worth at today’s exchange rate–is released.
Whoever solved the final hash gets the whole block. This all makes Bitcoin mining hyper-competitive with miners competing to solve more problems faster than their peers to increase their chances of getting a block.
The speed of a particular piece of mining hardware is measured in MegaHashes per second (MH/s), or if it is powerful enough, GigaHashes per second (GH/s). The world of Bitcoin mining is now dominated by specifically designed ASIC chips. These custom chips are orders of magnitude faster than CPU or GPU based miners and are available in USB devices that connect to a Mac.
My NVIDIA GPU averages a speed of around 25 MH/s while dedicated hardware such as this Bitcoin Miner from Butterfly Labs can get speeds of 10 GH/s for around the same price. This is to say nothing of the super high speed hardware available for thousands of dollars.
Bitcoin mining is also increasingly done in pools. A pool is a group of miners who work together to increase their chances of finding a block. The block is shared with all the miners in the pool, in proportion to the amount of hashes they solved, regardless of who actually found it. If you are mining by yourself, you could go years without ever finding a block, while, if you join a pool, you will at least be guaranteed a small, but steady, pay out.
Why You Shouldn’t Mine Bitcoin With a Mac
It was once possible to profitably mine bitcoins with a desktop computer, however, you will now end up spending far more on electricity bills than you ever make mining. Macs are no exception to this. Unless you are prepared to invest in specialised hardware, at the bare minimum something like Butterfly Labs’ 10 GH/s Bitcoin Miner, your returns are going to be miniscule.
Even if you join a pool, your share will likely amount to a few cents per day at most.
Why You Should Mine Bitcoin With a Mac
The future of Bitcoin is unclear. It is running into regulation issues, monopoly problems and over-mining. There are also some fundamental flaws with Bitcoin that make it’s use as a currency going forward questionable. Despite this, the ideas raised by Bitcoin are likely to become increasingly important.
Bitcoin, in principle, does for financial transactions what email did for communication–it makes it fast, free and available to all. Other crypto-currencies are being created that correct many of Bitcoin’s issues.
Crypto-currencies are something worth learning about. I am a firm believer that the best way to learn about something is to dig in and get your hands dirty. With Bitcoin, this means that you should engage in some unprofitable Bitcoin mining using a Mac!
Also, mining Bitcoin is fun. As I write this tutorial, my GPU is busy cracking hashes. By the time I am finished, I’ll probably have earned two or three hundredths of a cent. That’s kind of cool!
To mine Bitcoin on a Mac you’ll need a wallet with a wallet address. Refer to the Tuts+ tutorial that teaches how to set up the wallet service MultiBit. I also like MultiBit and suggest you download it from the MultiBit website. It is simple to set up but if you have any difficulties check out the tutorial.
You also need a Mac with a discrete GPU. This excludes all MacBooks bar the top 15-inch MacBook Pro with Retina display, and some models of 21.5-inch iMac. If your Mac doesn’t have a discrete GPU, you will need to pick up some of the external mining hardware described later on.
Joining a Pool
The best way to casually mine is to join a pool. Unlike mining solo, you will at least get a Bitcoin balance above zero! Slush’s pool is one of the most popular–they average more than one block discovered every day so you are guaranteed a frequent, small payout if you join in. There processing fee is also low–only 2%.
Visit the Slush’s pool site and sign up. You will need to confirm your email address. Once you are signed up you will be provided with your first worker username and password. Take these down. A worker is simply an individual mining computer.
Add your MultiBit wallet address to the Bitcoin address: section on the My account page and click Save. You can also lower the Send threshold–one coin requires quite a bit of mining.
The account page tracks how much your workers have contributed to the pool’s current round as well as your total earnings.
Mining Bitcoins With Asteroid
Asteroid is a free, Mac-friendly GUI frontend that makes it super easy to mine Bitcoins. Many other solutions require knowledge of the command line. Asteroid is just a regular app.
Download a copy from the Asteroid website, drag it to the Application folder and open it.
Asteroid comes preconfigured with the settings for the most popular Bitcoin mining pools. From the dropdown menu select Bitcoin.cz (Slush’s pool) and enter the Worker username and Worker password you took down earlier. Click Accept to join the pool.
Asteroid now begins mining Bitcoins for you. You can see the hashes being solved per second by each device as well as the overall speed of your Mac. Your GPU should be listed along with any additional mining hardware you have.
Mining Other Crypto-Currencies
Bitcoin is not the only crypto-currency. There are many other competing currencies that have a fraction of Bitcoin’s value.
You should consider mining a Bitcoin alternative–mining is far less competitive for them so you will see a larger return, at least in terms of coins, than with Bitcoin.
Asteroid also supports mining Litecoin, one of the leading competitors to Bitcoin, and Dogecoin, the semi-joke, meme-based crypto-currency.
If you are serious about mining Bitcoins, or if your Mac doesn’t have a GPU, you will need to invest in dedicated mining hardware.
The high end of dedicated mining hardware is just as competitive as mining itself. You can spend thousands of dollars to get the best available only to have something even better come out a short while later.
BitcoinX maintains a list of mining hardware representing some of the best, high end mining kit. If you want to get involved in mining for profit, this is a good place to start.
If you are merely trying to supplement your GPU, or mine with a system that doesn’t have one, the USB based Antminer U2 is available for under 30 dollars, is supported by Asteroid and provides speeds of around 2GH/s.
Unless you are prepared to invest in dedicated tools, mining Bitcoins with a Mac is never going to be profitable; however, it can be a fun learning exercise. Crypto-currencies are only going to become more important and it is worth understanding what they are and how they work. The software required is all free so the cost of playing around with mining is minimal.
In this tutorial, I’ve shown you how to get started mining with Asteroid on a Mac and explained why you may, or may not, want to do it. I’ve also covered some of the dedicated hardware and other crypto-currencies available. If you have any questions, or are a dedicated miner cracking millions of hashes a second with a Mac, please let me know in the comments below.